This chapter outlines legal and regulatory factors that impact the capacity to use graywater or stormwater for beneficial purposes. Water rights can be a barrier in some states, and local regulations related to water quality may limit potential uses. However, the legal and regulatory framework for the beneficial use of on-site water sources appears to be rapidly evolving.
Legal barriers related to the water quantity impacts of graywater or stormwater use primarily concern water rights laws, which determine the rights to the use of water. Other laws protecting threatened and endangered species may also have relevance to large diversions of water from streams.
State Water Rights Laws
Laws concerning the allocation of water, particularly surface water, determine the rights to stormwater and graywater and thus can significantly influence the harvesting and use of that water. Water allocation is regulated primarily at the state level. Although each state has a unique set of laws, nearly every state uses one of two doctrines—prior appropriation or riparian rights—and in some cases both, as the foundation for its water allocation (see Figure 8-1).
The prior appropriation doctrine is the sole or predominant system of water allocation used by most states in the western half of the United States (Getches, 2009). Under this doctrine, the right to use water is allocated based upon the historical order in which rights to it were acquired, hence the adage “first in time, first in right.” In essence, the oldest right is fulfilled, then the next oldest, then the next oldest, and so forth until there is no water left to disperse or all rights are fulfilled. Traditionally, a key tenet of the prior appropriation doctrine is the prohibition against impairing other water rights. Therefore, appropriative water rights are generally well protected in law, as well as in politics and cultural norms.
When downstream water right holders exist, the effect, or even the potential effect, of stormwater and graywater harvesting and use on water rights can pose a challenge to the application of these technologies in prior appropriation states. Large-scale stormwater capture could result in less water eventually making its way to the stream and, as a result, cause a water right that otherwise would have been fulfilled to not to be. The same possibly could be said for small-scale stormwater capture, such as rain barrels and cisterns, when widely used in existing developments. Concern about this potential impact could lead, and in some cases has led, to opposition by water right holders and caution by state regulators with regard to the development of such infrastructure. Because urban development increases stormwater runoff and reduces evapotranspiration,1 on-site stormwater capture systems (depending on their design) may have minimal impact on downstream flows compared to pre-development conditions. However, each western state has unique regulatory frameworks for governing water rights, which are not necessarily allocated based only on pre-development conditions.
Colorado is currently the only prior appropriation state with regulations that restrict the beneficial use of stormwater,2 although a pilot program is under way to gather data in new developments regarding the feasibility of stormwater capture for water conservation without injuring the water rights of others.3 Six prior appropriation states have developed regu-
2 An exception is allowed for rural residential property owners whose water is supplied by certain wells.
3 New developments that qualify as one of a limited number of pilot projects may harvest rainwater from impervious surfaces for nonpotable uses as long as the entire amount harvested is replaced to the stream by some other source. If, after a time, the development can calculate the amount of harvested rainwater that would have
lations to allow stormwater capture and use in some form, providing specific exemptions from water rights permitting, mostly for smaller-scale systems (see Table 8-1; supporting detail is provided in Table B-1 in Appendix B). Four of these six are coastal states, suggesting perhaps that states discharging stormwater directly to the ocean or Gulf of Mexico may be more willing to consider regulatory exemptions to water rights permitting for stormwater capture and use if the benefits within the state are judged to outweigh the negative impacts. Eleven prior appropriation states (all located inland) have not yet set regulations regarding stormwater use. Lack of specific regulations does not necessarily prohibit its use—three of these states have issued statements or tax credits that encourage the capture and use of roof runoff (Table 8-1). New Mexico specifically states “the collection of water harvested in this manner should not reduce the amount of runoff that would have occurred from the site in its natural, pre-development state.”4 However, it is possible that water right holders would sue owners of stormwater or graywater infrastructure for impairing their water rights, and the laws of the jurisdiction would heavily influence the success of such a suit.
Explicit laws concerning these matters are still relatively rare, and judicial interpretation of water appropriation laws for these purposes is in its infancy. Although the precise rights of water right holders to runoff and return flows are, on the whole, unresolved at this point, it is not unprecedented for courts to hold in favor of technological improvement and perceived efficiency over the water rights of others.5 The answer also may depend on whether the individual capturing and using the stormwater or graywater has a pre-existing water right.
The riparian rights doctrine is the sole system of water allocation used by 29 states (Getches, 2009). Borrowed from England, this doctrine grants the owners of land that abuts a natural stream, river, lake, or pond rights to that water. Most riparian rights states allow riparian landowners unlimited use of water for drinking, washing, and modest animal and garden needs and limit all other uses to “reasonable use.” Traditionally, if the reasonable needs of all riparian landowners cannot be met with the available water, then usage is reduced proportionately. Many states using the riparian rights
been consumed by evapotranspiration from native vegetation, the development can ask the water court for permission to not replace that amount.
5 See, e.g., Montana v. Wyoming, 131 S. Ct. 1765 (2011).
TABLE 8-1Examples of State Regulation of Stormwater Use
|Prior Appropriation States Without On-site Stormwater Capture and Use Regulationa||States with Regulations That Specifically Allow On-site Capture and Use||States with Regulations That Limit or Prohibit On-site Capture and Use|
|Alaska||California (rooftop capture exempted from water rights permitting)||Colorado|
|Idahoc||Kansas (domestic, <15 AF/yr)|
|Oklahoma||Utah (<2,500 gallon storage with permit or <200 gallon without)|
|South Dakota||Washington (<360 gallon storage without permit and for single family dwellings)|
aLack of regulation should not be interpreted as a prohibition on such activities.
bAlthough there is no formal regulation, Arizona has provided tax credits for rainwater harvesting systems.
cAlthough there is no formal regulation to this effect, the Idaho Deputy Attorney General issued an opinion that on-site rainwater may be captured for beneficial use as long as there is no injury to the water rights of others.
dAlthough there is no formal regulation, the New Mexico Office of the State Engineer encourages the capture and on-site use of roof runoff.
NOTE: See Appendix B-1 for details.
The right to unlimited use of surface water by riparian landowners for drinking, washing, and modest animal and garden needs should put stormwater and graywater use for these purposes squarely within the rights of riparian landowners. The use of that water for other purposes, to the extent that the total volume is less than what requires a permit, and perhaps even if more, would likely also fall within riparian landowner rights, although it might need to be “reasonable use” and might be subject to reduction in times of scarcity. Stormwater and graywater capture and use may be less secure for non-riparian landowners, if the harvested water otherwise would have flowed to a stream or river. However, rights to water before it reaches a natural watercourse, whether from runoff or discharge, may be even more tenuous in this allocation system than under prior appropriation. The concept of equity that underlies the riparian rights doctrine, coupled with the limited accounting of volumes used, results in rights to water that are more difficult to quantify, potentially dissuading lawsuits and political objections to stormwater and graywater harvesting and use.
Determining a Violation of Downstream Water Rights
With either allocation system, there is the possibility, however small, that a court finds state legislation allowing stormwater or graywater capture and use to result in a taking of a property right in water. The first step of that analysis would involve determining whether “property” is at issue and if “background principles of the State’s law of property and nuisance” already limited the property right.6 This involves asking at what point in the water’s migration does the right begin—for example, a roof, the ground, or its entrance into a natural watercourse. The answer to this question will depend on the laws of the jurisdiction and, in many states, has not been resolved. If the water right extends to the falling of rain and snow, then the remainder of the complex takings analysis must be conducted, the application of which to surface water rights neither has proven simple, nor is yet clear (Echeverria, 2010; Lock, 2000). Thus, additional court challenges may be necessary to fully clarify the legal framework for stormwater and graywater, particularly in prior-appropriation states.
Minimum Flows to Protect Aquatic Life
Reductions in streamflow that may result from stormwater and graywater capture and consumptive use have the potential to adversely affect not only water rights, but also the riparian ecosystems on which protected species rely. The U.S. Environmental Protection Agency (EPA), in its 2012 Guidelines for Water Reuse, highlighted the concern: “[t]he most significant constraint affecting use of reclaimed water is the need to assure instream flows sufficient to protect aquatic habitat. This is especially necessary in locations where instream flows are necessary to protect the habitat of threatened and endangered species” (EPA, 2012a). The federal Endangered Species Act, for example, has influenced many water allocation and use decisions, because of the potential to violate explicit protection measures for species, such as minimum instream flows, or the potential impact an action may have on a population of threat-
6 Lucas v. South Carolina Coastal Council, 505 U.S. 1003, 1029 (1992).
ened or endangered species themselves (Craig, 2008; EPA, 2012a; Getches, 2001). Although the committee is unaware of any specific examples where graywater or stormwater use is currently threatening instream flows to support endangered species, many states have established instream flow laws to protect species in over-allocated basins (Bonham, 2006), and concerns may arise in the context of extensive consumptive graywater and stormwater use in areas with the potential to affect important habitats.
Although water allocation systems are generally a matter of state law, federal, state, and local laws all influence the framework for water quality regulation as it relates to the beneficial use of stormwater and graywater. Although this section focuses on existing U.S. federal, state, and local laws, regulatory frameworks or water quality guidance from other countries (e.g., NRMMC, et al., 2009a,b) illuminate alternative strategies for managing water quality concerns.
Stormwater Capture and Use
Federal laws do not specifically govern the use of captured stormwater, but federal water quality laws may influence stormwater capture projects through the Clean Water Act (CWA) or the Underground Injection Control (UIC) program.
The Clean Water Act and National Pollutant Discharge Elimination System Permits. The Federal Water Pollution Control Act, commonly known as the Clean Water Act (CWA), serves as the foundation for water quality regulation by the federal government and the states. The CWA sets out broad water quality restoration and maintenance objectives and establishes a two-pronged approach to achieve them, combining effluent limitations with ambient water quality standards. Under the water quality standards program, states are directed to adopt water quality criteria for contaminants, based on the water body’s designated use (e.g., public water supplies, recreation, protection of fish and wildlife), which must be approved by the EPA as adequately protective of the public health and welfare (33 U.S.C. § 1313). The primary tool in the CWA for meeting these criteria is the prohibition against discharging pollutants from any “point source” into U.S. waters without a permit issued under the National Pollutant Discharge Elimination System (NPDES) (33 U.S.C. § 1342).
Most stormwater runoff discharges, such as those from certain construction sites and many categories of industrial facilities as well as municipal separate storm sewer systems (MS4s), fall under the definition of “point source,” and thus require a NPDES permit (EPA, 2012c). The permits, which are issued by authorized states7 or the EPA, can include requirements for site-level stormwater management plans or programs. Traditionally, stormwater management practices have relied mainly on “end-of-pipe” treatment best management practices (BMPs; e.g., filters) to trap or remove pollutants shortly before the water is discharged to reduce the quantity of pollutants that reach surface waters. However, an emerging trend favoring low impact development (LID) encourages implementation of “green infrastructure” to mimic an area’s natural hydrology by retaining and managing stormwater on-site (see Chapters 1 and 6; EPA, 2014a). LID includes various measures to reduce impervious surfaces and thus allow infiltration of water into the soil and the capture and storage of stormwater for use or timed release.
Despite increasing recognition of the environmental, social, and economic benefits of green infrastructure (see Chapter 7), many local stormwater permits, administrative orders, and other enforceable documents that hold permittees to their stormwater management obligations under the NPDES program have not been updated to include these alternative approaches (Stoner and Giles, 2011). Existing legal requirements with a historical preference for end-of-pipe BMPs are likely to act as a deterrent to some facilities’ and municipalities’ adoption of stormwater capture and use, unless permittees can be confident they will receive legal credit (EPA, 2010). Thus, even though EPA has developed the Green Infrastructure Action Strategy to encourage the incorporation of LID into stormwater management planning (EPA, 2008a, 2013a), current regulatory and enforcement programs leave many permittees unable or unwilling to implement alternative BMPs (Stoner and Giles, 2011). EPA continues to work to address this issue (EPA, 2013a) and has developed extensive guidance for state and EPA NPDES permitting and enforcement staff on integrating green infrastructure approaches into permits, control plans, and consent decrees.8
Numerous states and municipalities are adopting policies and tools to grant LID practices legal credit and “put it on a
7 Forty-six states are authorized to issue NPDES permits. The EPA currently implements the NPDES permit program for Idaho, New Mexico, New Hampshire, Massachusetts, the District of Columbia, and tribal lands. See http://water.epa.gov/polwaste/npdes/basics/NPDES-State-Program-Status.cfm.
level playing field with other BMPs” (EPA, 2013b). States such as Virginia and North Carolina are developing stormwater regulations that acknowledge the water quality benefits related to reductions in stormwater volume (EPA, 2013b). In southern California, several recently adopted MS4 stormwater permits require the on-site retention of a large percentage of expected runoff from rain events using a set of LID practices that includes rainwater capture and use (Strecker and Poresky, 2010). At the federal level, the 2007 Energy Independence and Security Act set green infrastructure requirements in federal development and redevelopment projects, calling for “strategies for the property to maintain or restore, to the maximum extent technically feasible, the predevelopment hydrology of the property,” which has been interpreted by the EPA to require on-site retention of the 95th percentile storm event (42 U.S.C. § 17094; EPA , 2009).
Underground Injection Control. Federal or state UIC Class V regulations govern projects that use shallow injection systems (including wells, dry wells, and manufactured infiltration chambers) to speed infiltration of captured stormwater into the subsurface. These UIC regulations are designed to protect potential sources of drinking water from contamination. Most stormwater infiltration practices (e.g., infiltration trenches, bioretention basins) do not meet the EPA Class V well definition (“any bored, drilled, driven shaft, or dug hole that is deeper than its widest surface dimension”) and can be installed without regulatory oversight, provided they meet any set state criteria protecting groundwater supplies (EPA, 2008b). Existing stormwater UIC regulations vary in structure and approach from state to state. For example, in Florida, Class V wells must be constructed so that they do not violate water quality standards at the point of groundwater discharge. California is more stringent in its regulations and prohibits any degradation in water quality while stored, a rule that can impose costly pretreatment requirements (NRC, 2009a). Because of concerns over potential groundwater contamination by direct injection or the costs of pretreatment, many projects instead use surface infiltration, which can be installed without federal oversight. Those that meet the Class V criteria can be operated without an individual permit, provided the injection does not endanger an underground source of drinking water and the operator submits basic inventory information to the permitting authority (EPA, 2013c).
State and Local Regulations Relevant to Stormwater Use
Only a few states have regulations that specifically address the use of stormwater as an on-site water supply (see Table 8-1). The legality of stormwater capture and use in the remaining states is, in many cases, less clear, but the lack of formal regulation should not be interpreted as a prohibition on such systems. In fact, some cities or states without formal regulation have promoted and issued detailed guidance for installing on-site stormwater capture and use systems (e.g., City of Tucson, 2005; Minnesota’s Stormwater Manual [MPCA, 2015]). State and local regulations on stormwater use for on-site water supply are evolving quickly as the practices are becoming more widespread. Yet, even in states where stormwater capture and use is allowed and encouraged through specific regulations (see Appendix B) or guidance, state and local public health codes may limit potential beneficial uses or system designs. Underground injection control regulations may also impact how states are permitted to infiltrate stormwater in larger scale projects.
Regulations on Stormwater Water Quality Criteria or System Design. Responding to citizen interest and concerns about water conservation and stormwater management, at least 10 states have developed specific regulations on stormwater capture and use (Table 8-1). These regulations vary widely in complexity and consideration of possible uses (see Table B-1) and may be written from a range of perspectives, including public health, environmental management, or tax crediting. Many provide basic requirements for the design and permitting of stormwater capture systems, such as that described in the 2012 Uniform Plumbing Code (UPC; see Box 8-1), which as of December 2014 had been adopted (at least in part) by several states, including California, Hawaii, Iowa, and Washington. Other states have developed detailed, but not legally enforceable, guidance for developing stormwater capture and use systems (e.g., Carpenter et al., 2009). Many state regulations (and the 2012 UPC) limit water collection to roof runoff, although California allows collection from surface runoff, including paved roads and parking areas, as long as the water is used exclusively for subsurface irrigation or treated to applicable local water quality requirements (or National Sanitation Foundation [NSF] 350 in absence of such requirements; see Box 6-2). NSF-350 was developed for wastewater reuse systems and does not provide risk-based guidance for stormwater capture and use (see Chapter 6). Many of the state regulations (e.g., Utah, Washington) also provide permitting exemptions or reduced requirements for small rooftop harvesting systems used only for outdoor irrigation.
As of December 2014, only one state—California—had established specific water quality criteria for stormwater use projects. Box 8-2 summarizes water quality guidance or requirements for four states, which vary substantially. Additionally, local governments may establish their own water quality criteria. For example, Los Angeles County Depart-
ment of Public Health established extensive tiered guidelines for outdoor uses of stormwater, ranging from no water quality criteria for rain barrel collection systems to rigorous permitting and monitoring requirements for systems with stormwater draining from industrial, high-traffic, or agricultural areas (see Table 8-2). However, Los Angeles County does not yet have water quality guidelines for indoor uses, such as toilet flushing.9 The lack of a consistent, authoritative source for water quality criteria that could be adopted by state or local governments serves as a major impediment to expanding the use of stormwater for indoor or large-volume
9 In early 2016, after the release of this report in prepublication form, the Los Angeles Department of Public Health released new guidelines for both indoor and outdoor nonpotable uses of graywater and stormwater. See http://publichealth.lacounty.gov/eh/docs/ep_cross_con_AltWaterSourcesGuideline.pdf.
outdoor uses. Even when water quality guidelines are established, communities may lack mechanisms for regulatory oversight of these requirements.
Regulations to Prevent Health Hazards from Standing Water. Large quantities of nonpotable standing water may create public health hazards associated with mosquito breeding, use of contaminated water, and algae growth. Therefore, some states with stormwater use regulations or guidelines have included express requirements aimed at public health protection, such as requiring opaque tanks to inhibit algal growth and screens to limit mosquito breeding (e.g., WVDEP, 2012; see also EPA, 2013b). However, in jurisdictions where the capture of roof runoff is not formally regulated or ex-
TABLE 8-2 Summary of Los Angeles Tiered Guidelines for Stormwater Capture and Outdoor Use
|Requirement||Uses||Water Quality Standard||Treatment|
|Roof runoff collected in rain barrels with on-site use (Household scale)||
|Roof runoff collected in cisterns with on-site use|
|(Large household scale; no source water from agricultural, manufacturing, or industrial land uses)||
|Tier 3 On-site or off-site stormwater collection in cisterns; off-site or onsite use (No high transportation corridors or agricultural, manufacturing, or industrial land uses)||
Same as Tier 2 spray irrigation
On-site or off-site stormwater collection in cisterns; off-site or onsite use (Includes high transportation corridors or agricultural, manufacturing, or industrial land uses)
Same as Tier 2 spray irrigatio
aSpray irrigation is only allowed when there is negligible human exposure, such as after sunset and before sunrise.
SOURCE: Los Angeles County Department of Public Health (2011).
emptions have not been established, increased amounts of stagnant water (in cisterns or infiltration basins) may violate state or local public health laws that require private property owners to prevent conditions that contribute to vector harbor-age, which is typically considered a public nuisance. In Connecticut, for instance, the state environmental commissioner is empowered to issue orders aimed at eliminating mosquito-breeding places (Connecticut Gen. Stat. § 22a-45b), while local health authorities are required to investigate reports that rain barrels or other receptacles near human habitations are breeding mosquitoes and cause any such breeding places to be abolished, screened, or treated (Connecticut Gen. Stat. § 19a-213). An ordinance adopted by the city of Petersburg, Virginia, allows its health director to order occupants of private property to drain standing water that is detrimental to the health, comfort, or general welfare of any of the inhabitants of the city (Petersburg, Va. Code of Ordinances § 50-64). In extreme cases, adverse effects on a neighbor’s use and enjoyment of property caused by vectors or odors also could leave a stormwater harvester vulnerable to private nuisance liability.
No federal laws directly govern on-site management of graywater, leaving to the states policy decisions about whether and how to regulate on-site graywater reuse.
State Graywater Reuse Laws
Although some states have recognized graywater as legally distinct from wastewater for many years and have even encouraged segregated plumbing and reuse, a relatively recent surge of interest in graywater use as a conservation alternative has prompted a flurry of new legislation. As of December 2014, at least 26 states have laws allowing segregation and reuse of graywater under less stringent treatment standards than those applied to reclaimed wastewater (see Table 8-3 and Appendix B, Table B-2).
State regulations are widely variable with respect to allowable graywater reuse applications and treatment requirements (Yu et al., 2013). As a threshold matter, states differ in what sources of household water are included in the defini-
TABLE 8-3 Summary of State Regulation of Graywater Reuse
|States Without Formal Graywater Regulations||States with Regulations Allowing Graywater Reuse|
|States allowing wastewater reclamation that define graywater as wastewater||States not defining graywater||States treating graywater as septic||States permitting graywater using a tiered approach||States regulating graywater reuse without a tiered approach||States allowing graywater for irrigation uses only|
|Arkansas||South Carolina||Maryland||New Mexico||Georgia||Kansas|
|Mississippi||New Hampshire||New York (non-residential)||Oklahoma|
|Missouri||New Jersey||North Carolina||Utah|
|Pennsylvania||West Virginia||South Dakota|
SOURCE: Updated from Sharvelle et al. (2013).
tion of “graywater”—generally faucets and showers, sometimes laundry, and sometimes the kitchen sink or dishwasher. In addition, states differ on where within their statutory and regulatory codes they cover the topic: plumbing or building codes, sewage disposal regulations, water pollution control regulations, health and safety codes, water and wastewater regulations, or a distinct section of code dedicated to graywater reuse requirements (Yu et al., 2013). The location and thoroughness of a state’s graywater provisions may be indicative of its general priorities and objectives with respect to graywater reuse.
States in arid regions, where ever-growing pressure on municipal water supplies has prompted widespread interest in reuse, tend to have the most comprehensive graywater reuse regulations or guidance (Martinez, 2013). For example, California—the first state to adopt legislation promoting graywater reuse in 1992—has updated its graywater regulations several times to establish a workable framework for regulating residential and nonresidential graywater systems (Snodgrass, 2010). Arizona’s tiered permitting system is widely considered a model of effective regulation for graywater irrigation (see Table B-3 in Appendix B).
In tiered regulatory frameworks (see Table 8-3), the requirements for permitting increase with the size of the system and the expected human exposures. For projects with large volumes captured for beneficial use, permitting may require design review, site inspections, and monitoring to ensure adequate public health protection. However, many tiered frameworks and some nontiered regulations allow the on-site reuse of small volumes of graywater without a formal permit. Some policy analysts have noted that when a permitting process is too burdensome and is perceived by potential small-volume users as an added cost, it may have the effect of discouraging installation of graywater systems or incentivizing unauthorized reuse (Snodgrass, 2010; Yu et al., 2013). In fact, states where on-site graywater reuse is considered to be comparatively widespread also tend to be states whose regulatory schemes allow small volumes of graywater to be collected and reused without obtaining a formal permit—Arizona, California, New Mexico, Montana, Texas, and Wyoming.
Among states with graywater regulations, there are numerous differences with respect to allowable uses, permissible equipment, and treatment/water quality standards. For example, Table 6-4 highlights varying graywater quality standards for toilet flushing in seven states, and Table 8-3 summarizes the different regulatory strategies and end use limitations used by states (see Table B-2 for more detail). Yu et al. (2013) suggest that this inconsistent regulatory landscape may be a barrier to graywater implementation. Specifically, the varied scales for which on-site systems are allowed and to what purposes the water may be put can keep the cost of available infrastructure products on the market high because the manufacturing industry cannot reach optimum scales of production. Additionally, lack of consistent, authoritative risk-based guidance may deter local or state governments from establishing their own regulations where they do not already exist or may lead local or state health departments to question the safety of these applications.
Where water quality standards have been established for household- or neighborhood-scale systems, enforcing those standards and developing cost-effective regulatory or over-
sight mechanisms to ensure the systems are appropriately maintained is a challenge. As noted in Chapter 6, additional maintenance and monitoring guidance is needed, with clear performance standards and possible online monitoring of surrogate parameters for neighborhood- or large-building-scale systems. As part of San Francisco’s Non-potable Water Program, the San Francisco Department of Public Health oversees water quality and monitoring requirements for graywater and stormwater use at multi-residential and commercial sites (see Box 8-3).
Graywater Provisions in Plumbing Codes
Even in states without comprehensive graywater regulations, special provisions for graywater systems can sometimes be found in plumbing codes (see Box 8-1). In a number of states, the plumbing code includes separate standards for the design and operation of on-site graywater reuse systems. The UPC and IPC, each of which has been adopted by many states, are the two most prevalent model plumbing codes. These model codes identify permissible graywater reuse procedures and contain treatment specifications for graywater according to categories of use (see Box 8-1). These model plumbing codes generally restrict legal use of graywater to use that limits human exposure to pathogens—namely, subsurface irrigation and toilet flushing—and specify any treatment necessary (Yu et al., 2013). Provisions in a plumbing code also address cross-connections, backflow valves, air gaps, and other aspects of plumbing configuration, which may determine not only whether a certain system is permissible, but also how the system is installed and how efficiently and economically it operates (Sharvelle et al., 2013). For example, the 2012 IPC requires a graywater storage tank for subsurface irrigation, which would prohibit the more economical, household-scale, laundry-to-landscape systems described in Chapter 6.
On-site Wastewater Disposal Laws
Even in states where the plumbing code accepts graywater for a limited class of nonpotable uses, the legality of reuse may ultimately be determined by wastewater disposal laws designed to protect drinking water supplies and regulate the entry of polluted water into the environment. On-site wastewater disposal laws affect the application of graywater to soil, which occurs in the course of the most common outdoor uses of graywater (e.g., subsurface irrigation). On-site wastewater disposal systems are permissible in many states under certain conditions. Some states only allow on-site disposal systems where public sewer connections are impossible or overly burdensome, but many are now also recognizing “innovative” or alternative on-site systems. In a number of states, graywater can be applied to subsurface irrigation under these laws as part of the general domestic wastewater stream.10 However, some on-site wastewater disposal codes allow segregation and application of graywater at lower treatment standards than water that may contain sewage. In Maine, for example, the on-site wastewater disposal code permits “primitive” or “limited” graywater disposal to water plants with untreated graywater by hand (Code of Maine Regs. § 10-144-241).
Despite increasing recognition of graywater systems as attractive disposal alternatives, in some states the inconsistencies between plumbing code provisions and state or municipal on-site sewage and health codes may yet constrain a property owner’s ability to legally implement a graywater reuse system (Snodgrass, 2010). In extreme cases, as in South Carolina and Maryland, a state may have regulations for graywater systems in its plumbing code, yet have public health or sewage disposal laws requiring all domestic wastewater to be discharged to the sewer system (Sharvelle et al., 2013). In other cases, it is unclear whether a law allowing subsurface application of graywater as a means of “disposal” has the effect of authorizing the application of graywater for subsurface “irrigation.” These contradictions and ambiguities within a state’s own code can create direct legal obstacles to implementation. To make matters still more complicated, the agency responsible for enforcing building codes and issuing permits for indoor plumbing installations may differ from the public health or environmental agency charged with regulating any storage or application of graywater that occurs outside the building and/or the agency that regulates beneficial use of water resources.
Potential Procedural Barriers
State and federal environmental impact analysis (EIA) laws provide varying levels of procedural and, on occasion, substantive protections of the public’s interests. EIA laws seek to identify risks in advance of a project; balance environmental and socioeconomic values; ensure opportunities for stakeholder participation; and demand informed, reasonable decision making. Since EIA’s emergence, litigation has played an important role in achieving these objectives (Taylor, 1984; Wathern, 1988). Federal projects are subject to the environmental review requirements of the National Environmental Policy Act (NEPA) (42 U.S.C. § 4331 et seq.), and many states have enacted “little NEPAs”—state EIA statutes that apply the same general principles to state
and municipal projects (Bender, 2014). Some of these state laws, notably the California Environmental Quality Act, define “project” and “environmental impact” quite broadly so that many government actions—from large-scale projects to permitting decisions and even policy changes—are subject to the environmental review requirements (California Public Resources Code § 21000 et seq.).
Although few of the state EIA laws include substantive provisions—and only a small percentage of the legal challenges result in the court prohibiting a project from ultimately moving forward—opponents of proposed actions who can credibly argue that a project’s potential environmental impacts will injure them often can influence the how and when of a project through EIA litigation (Riccardi, 2011; Wathern, 1988). Particularly in states where EIA laws are robust and litigated often, for example California, actions that alter downstream flows may face the additional hurdle of litigating claims brought under EIA laws.
Significant future expansion of graywater or stormwater to meet water supply needs raises a number of policy issues to be addressed by local, state, or national governments. These issues involve water quality standards, source control, downstream impacts, and decentralized infrastructure.
As discussed in this chapter, few states have water quality regulations or guidance for graywater and stormwater use, and those that exist are widely variable (see Box 8-2 and Table 6-2). National guidance is lacking in the United States, although Australia has developed extensive guidelines on the use of stormwater and graywater (NRMMC, et al., 2009a,b). The 2012 EPA Water Reuse Guidelines are often cited as a reference, although its categories of recommended water quality criteria are broad and lump spray irrigation, fire protection, and toilet flushing—categories with far different exposures—into a single category of “urban uses,” resulting in suggested water quality criteria that may be more protective than needed to protect public health. EPA (2012c) may be more useful for large-scale, groundwater infiltration projects or industrial applications. However, the wastewater sources considered in the development of these recommendations are significantly more contaminated with microorganisms and may contain lower concentrations of other contaminants, such as metals and organic contaminants found in urban, stormwater-draining, paved areas. Without risk-based guidance, local projects may face resistance from health departments or the public, who question the safety and reliability of these practices, or may lead to unnecessary treatment (and associated cost) to meet overly restrictive guidelines that were developed for different risk scenarios (or may not be risk-based at all). Therefore, additional risk-based water quality guidance is needed that can serve as the basis for developing standards of practice for typical stormwater or graywater applications. Fit-for-purpose guidelines will require substantial public education so that on-site waters are used appropriately with the necessary treatment.
Increased use of urban stormwater, particularly at large scales, leads to water quality concerns with runoff from roadways, parking lots, and industrial areas (see Chapter 4). Treatment is an important component of large stormwater systems, but policy issues emerge about the role of enhanced source control in areas that rely upon urban stormwater to recharge potable aquifers. Limits on roofing materials, road salt application, or even tire or brake pad composition could lead to significant improvements in stormwater quality (see Chapter 4), but policy makers should weigh the costs and benefits of additional source control restrictions.
As the on-site water capture and use movement grows, particularly for consumptive uses such as irrigation, ecosystems and communities downstream will be impacted if the total volume of water used for irrigation exceeds that under prior conditions with only potable water use (see Chapter 3 and Box 3-3). Thus, policy makers should evaluate the benefits of on-site water use for various applications compared to the risks of harm to those downstream. In some prior appropriation states, the legal framework restricts the use of on-site graywater or stormwater out of concern for impacts to downstream water rights holders. However, impacts to downstream ecosystems, including streams and estuaries, also need to be considered. Although enhanced stormwater infiltration projects should increase base flow to streams, stormwater capture projects for expanded irrigation could decrease stream flows, and such effects should be carefully assessed in advance (see Chapter 3). Graywater and stormwater projects for nonconsumptive uses, such as toilet flushing, do not impact the quantity of water delivered downstream and are, therefore, ideal applications in inland communities.
Fully embracing the use of on-site water sources at household, neighborhood, and municipal scales requires a shift to decentralized treatment systems that ultimately supplement larger centralized facilities. This shift may have important policy implications in the way these decentralized facilities are permitted, managed, monitored, and maintained, particularly for communities with entirely centralized water and wastewater systems. Additionally, the intersection of green building practices, stormwater management, and water supply brings together a diverse array of local government entities with a role in managing these decentralized projects. Thus, neighborhood- or municipal-scale implementation requires the involvement of agencies responsible for city plan-
ning, water supply, wastewater, stormwater, building safety, and public health, possibly necessitating new strategies for government collaboration (see Box 8-3).
Finally, advances in potable water conservation (including but certainly not limited to graywater and stormwater capture and use) reduce the incomes of water and wastewater utilities, whose costs do not necessarily decline proportionally with water use (Beecher and Chesnutt, 2012). In growing cities, conservation allows utilities to serve more customers without the need to invest in expensive new water sources. However, when conservation causes total utility incomes to decline, increased rates, supplemental fees, or new rate structures may be necessary to maintain water utility operations (Donnelly and Christian-Smith, 2013).
As technologies and strategies continue to advance, graywater and stormwater use is being incorporated into law in a variety of respects at the federal, state, and local levels. A number of new laws at the state and local levels promote or regulate stormwater and graywater capture and use, and model plumbing codes have been updated to include provisions for these practices. Additionally, green infrastructure practices, including stormwater capture and use, are increasingly being incorporated into NPDES permits. However, as is often the case with innovative technologies, the law has not evolved quickly enough to keep up with advances in the technology and its use. Several legal and regulatory constraints remain that hinder the capacity for graywater and stormwater to significantly expand the nation’s water supplies.
In most western states, acquisition of water rights is a requirement for large-scale stormwater capture and use projects, and water rights may limit widespread implementation of smaller-scale stormwater and graywater projects for consumptive uses. The use of graywater and stormwater for consumptive applications, such as irrigation or cooling, may impact the water available to downstream users if total water use (including potable and nonpotable) for those applications exceeds previous potable water use (see Chapter 3). Thus, unless water rights can be acquired or legislative solutions developed, opportunities for large-scale stormwater capture projects to expand existing water supplies could largely be limited to coastal regions with no downstream users or to nonconsumptive uses (e.g., toilet flushing). Several states (e.g., California, Kansas, Oregon, Utah, and Washington) have established regulations that allow small-scale roof runoff capture projects to proceed with-
out water rights permits, and only one state (Colorado) has strict limits on stormwater capture and use out of concern for water rights impacts. However, the right to stormwater and graywater use in most prior-appropriation states has not been firmly resolved through judicial decisions, leaving an unclear outlook for projects that have not acquired water rights, because they could be vulnerable to legal challenges. New scientific analyses of the impacts to return flows of various on-site water uses in different regions would help clarify these concerns, but additional legal research and guidance could better facilitate the use of on-site water supplies, considering potential legal challenges.
There is substantial variation in on-site graywater and stormwater regulations at the state level with respect to design and water quality, which leads to varying exposures and risk. As one example, there is lack of consistency among states on whether outdoor graywater use is limited to subsurface irrigation. At least three states allow drip irrigation without landscape cover, which could lead to higher pathogen exposures. In addition, states vary on their regulation of untreated graywater irrigation of food crops. Whether such exposures would lead to unacceptable risks at various scales has not been definitively resolved, but higher risks are likely with increased exposures. Regulations affecting large-scale graywater and stormwater use where public access is not controlled tend to include conservative public health protections, such as disinfection, and meeting state maximum contaminant levels, but household-scale protections are more variable.
The lack of authoritative, risk-based guidelines for the design and potential applications of graywater and stormwater in the United States is a major impediment to their expanded use. The wide variability in existing regulations and absence of federal guidance leaves stakeholders and local decision makers uncertain about the safety of these practices and the appropriate level of treatment necessary for particular uses. Development of rigorous, risk-based guidelines for graywater and stormwater across a range of possible uses and exposures could improve safety, build public confidence in the practices, reduce expenditures on unnecessary treatment, and assist communities that lack an existing regulatory framework for on-site water supplies. Such guidelines could be developed by the EPA, a collaboration of states, or a collaboration of U.S. water organizations, including the Water Research Foundation, WateReuse, and the Water Environment Research Foundation working with the EPA. The Australian Guidelines for Water Recycling provide a useful example of such an effort. This guidance can then serve as a basis for developing standards of practice for on-site, nonpotable water use. Oversight and enforcement of water quality standards for applications with significant exposures is also important but challenging, and local enforcement agencies would benefit from additional guidance on appropriate, cost-effective maintenance, monitoring, and reporting strategies.
Inconsistencies often exist between plumbing codes and public health or on-site disposal laws within the same state, especially in the case of graywater, that need to be resolved to ease project implementation. Increased use of graywater and stormwater will require enhanced collaboration among agencies with jurisdiction over different elements of on-site water systems, including wastewater disposal, water supply, public health, pollution prevention, building safety, and city planning. As regulators continue to update laws to reflect increasing acceptance of new water reuse systems, legal barriers such as inconsistent or conflicting regulations are likely to be resolved.