the treated effluent and when and how the owner can use the resource. Another perspective is to ask whether the use of wastewater constitutes a “new” water supply; it might in a region where flows otherwise are released to the ocean, but not in a region where a downstream user relies on them.

Approaches to Water Reuse Under the Prior Appropriation Doctrine

The primary conflict with respect to water rights stems from downstream water rights holders and the potential for reuse activities to impair their use of the water. Some states give water treatment facilities greater rights to treated water, whereas other states may protect downstream senior rights holders. If the water reuse proponent must purchase a separate water right to the wastewater (i.e., the locality does not have the right to retain its treated wastewater), the costs of reuse will increase substantially.

In general, the owner of a wastewater facility has the ability to reuse the water without purchasing it from another. However, this is not always the case. In Utah the right to reuse must be specified in the operator’s water permit, and in New Mexico the operator’s right to wastewater may be dependent on its consumptive rights (which can be less than the water it discharges). In the following paragraphs, a brief survey of how states have approached the reuse of wastewater is presented.

In Colorado, wastewater can be used by the municipal wastewater treatment plant owner when the water is “developed” water. The term is used to describe water that is not natural to a stream, such as water imported from another basin or pumped from groundwater. These wastewaters would be available for use by the city that operates the wastewater treatment works. This concept provided the ability for Denver to reuse waters that had been piped from the Colorado River basin into the Platte basin (Tarlock, 2009).1 Further, the courts have held that there is no right in downstream entities to appropriate wastewater of another if that water has been “developed.”2

California’s reuse statute provides that “The owner of a waste water treatment plant operated for the purpose of treating wastes from a sanitary sewer system shall hold the exclusive right to the treated waste water as against anyone who has supplied the water discharged into the waste water collection and treatment system” (California Water Code § 1210).

In Utah, the right to reuse water must be specified in the original water right where wastewater reuse is included as a beneficial use (Schempp and Austin, 2007). A public agency that owns or operates a wastewater treatment facility may use, contract for the use, or reuse such water obtained under a water right under certain conditions.3 Water rights do not automatically attach upon treatment. Most basins in Utah are fully appropriated, and therefore a significant part of the reuse program is dependent on contractual arrangements that provide wastewater treatment facility owners with rights to the treated wastewater (Schempp and Austin, 2007).

In Arizona, the State Supreme Court held that the entity that treats the wastewater is entitled to put it to any reasonable use.4 This essentially provides wastewater reuse facilities the rights to all the water they treat. The court explained that the rule “will allow municipalities to maximize their use of appropriated water and dispose of sewage effluent in an economically feasible manner.” The court added that “the spirit and purpose of Arizona water law … is to promote the beneficial use of water and to eliminate waste of


1 See City of Thornton v. Bijou Irrigation Co., 926 P.2nd 1, 65-78 (1996).

2 The issue of water rights and water reuse was determined by the Colorado Supreme Court beginning with Burkhar v. Meiberg, where the Colorado Supreme Court determined there was no vested right to the captured irrigation wastewater of another (86 P. 98 (1906)). In 1972, the court in Metro Denver Sewage v. Farmers Reservoir recognized that this “wastewater rule” was also applicable to municipal wastewater effluent (499 P.2d 1190 (1972)). Subsequently, the court clarified the wastewater rule distinguishing that wastewater, as opposed to return flow and seepage, was not subject to appropriation by downstream entities (City of Boulder v. Boulder & Left Hand Ditch Co., 557 P.2d 1182 (1976)).

3 Such restraints include that the water right is administered as a municipal water right, the reuse is consistent with the underlying water right, and the reuse is approved by both the Utah Water Quality Board and the State Engineers Office (Utah Code Ann. § 73-3c-201(1) and 73-3c-202(1)a-c.

4 Senior water rights holders downstream from a municipal wastewater treatment plant alleged impairment as a result of the treatment plant’s sale of its treated effluent to other parties, which significantly decreased discharges to the stream. The court held that “the ‘producer’ of the effluent is a senior appropriator, those who have appropriated the effluent gain no right to compel continued discharge.” Ariz. Pub. Serv. Co. v. Long, 773 P.2d 988, 991-97 (Ariz. 1989).

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