Like much of the western and southwestern U.S., California has experienced drought conditions on and off for decades. Fortunately, the regulatory landscape is starting to catch up with water treatment technology, paving the way for states and localities to effectively create a new and reliable supply of potable water.

Since 2010, the California State Water Resources Board (the Board) and the California State Legislature (the Legislature) have studied the potential use of an emerging water recycling process known as direct potable reuse (DPR). DPR treatment involves an extensive, innovative, six-part filtering process that results in treated water being directed immediately back into the municipality’s drinking water supply.

Only one other state — Colorado — has enacted regulations at the state level that explicitly authorize DPR, but other states such as Florida and Arizona are following suit. State authorization is an important step, and it means that municipalities and drinking water treatment operators can evaluate DPR with a backdrop of regulatory certainty, and the public can be confident that the water supply is safe.

DPR stands in contrast to the indirect potable reuse (IPR) recycling method. In IPR, wastewater is: (i) filtered (to a lesser extent than DPR), (ii) directed into a “buffer” body of water (sometimes many miles away from the initial treatment plant), and (iii) converted to potable water at a local treatment plant. The benefits of using DPR include reducing reliance upon imported water, preserving buffer bodies of water (especially in times of drought), minimizing the need for building extensive pipeline systems to transfer treated water to buffer bodies of water, and providing a means of water production even during natural disasters in some cases.

On December 19, 2023, the Board adopted regulations authorizing local agencies to apply DPR treatment. The Board’s newly adopted DPR regulations are pending final review by California’s Office of Administrative Law before taking effect. But once published later this year as Article 10 of Chapter 17, Division 4, Title 22 of the California Code of Regulations, local agencies may begin using DPR treatment.

At its core, Article 10’s 63-page framework establishes important guidelines:

• Treatment Guidelines: Provides (i) maximum levels of certain agents or contaminants in DPR water, (ii) reporting requirements during every interval of the DPR process, and (iii) permitting requirements to allow for the use of DPR by a local water agencies. See Draft Regulations of Cal. Code Regs., Tit. 22, Ch. 17, Art. 10, “Draft Regulations” §§ 64669.60, 65, 90 (Oct. 4, 2023).
• Construction Guidelines: Requires coordination with design and engineering professionals to ensure that the “design and operation of the entire [DPR] treatment train … and connected facilities such as storage tanks, detention basins, reservoirs, related pipelines, and water conveyance … provide continuous mixing of the [water] flow along the path of flow between the terminus of the wastewater collection system and the entry point to the drinking water distribution system.” See Draft Regulations, § 50.
• Engineering Guidelines: Requires an engineer to verify that the entity seeking to implement DPR has the appropriate infrastructure in place to comply with Article 10 and re-verify compliance therewith every five years. § 64669.75.
• Funding Guidelines: Allows local water agencies to develop an agreement with a “partner agency” (defined as a “wastewater management agency, wastewater collection agency, public water system, or any other entity responsible for water treatment, water conveyance, or storage) to help share the costs of implementing DPR. § 64669.20.

Entities interested in implementing DPR should consider the feasibility of: (i) remodeling their current facilities, (ii) building new facilities for DPR infrastructure, (iii) establishing partner agreements with other entities to spread the initial and long-term costs, and/or (iv) qualifying for certain funding such as California’s Water Recycling Funding Program.

Public-private partnerships for construction projects — i.e., those between states and municipalities and private companies — could also help make implementing DPR more feasible. For instance, the public-private partnership model helps spread initial and long-term costs and reduces the amount of public money that would otherwise be tied up.

In California, a “governmental agency may solicit proposals and enter into agreements with private entities” to design and construct “fee-producing infrastructure projects … [including] sewage treatment, disposal, and water recycling.” Cal. Gov’t Code § 5956.4. As with most public-private partnerships, entities seeking to engage in a public-private partnership transaction will also have to navigate compliance with various legal requirements such as such as procurement and labor-law requirements. Considering the complex legal landscape among both the new DPR regulations and public-private partnership laws, agencies interested in implementing DPR are encouraged to consult with an attorney at the firm to help provide guidance and counseling to make DPR a reality.