Are You Ready For The New Water Reuse Regulations?

For decades, California has taken the lead in setting standards for water reuse. Other
parts of the U.S. that have struggled with water stress or scarcity have used the
state’s Title 22 regulations as a benchmark for their own guidelines or need-based
treatment designs. On Oct. 1, 2024, California’s new Title 22 regulations took
effect, which include guidance on direct potable reuse (DPR). Within the state,
continued treatment investigation and investment are expected. Even outside
California, water utilities, regulators, manufacturers, and design engineers
should understand these new guidelines, the processes, and the technologies they
cover in order to prepare themselves for implementation.

What’s New With Title 22?

Although Title 22 water regulations date back to 1978, groundwater recharge guidelines were first included in the early 2000s. In 2016, rules were added on indirect potable reuse (IPR), which requires a surface water barrier between wastewater discharge and drinking water intake. 

The most recent update establishes rules for DPR, eliminating the reliance on groundwater or surface water. It defines the criteria for a multi-barrier approach to ensure the water is treated to meet or exceed drinking water standards established in the state’s Safe Drinking Water Act. Regardless of controlling pathogens or chemicals, the regulations require three diverse treatment mechanisms with configurations and log reductions varying based on the control target.

While individual technologies and alternatives are specified in the update, San Diego Pure Water, which was an early test and adoption site for advanced treatment, proactively leveraged a diverse three-stage treatment mechanism that acts as a logical starting point for many DPR applications. It includes:

• Ozonation and biologically activated filtration (O3-BAF). This process uses ozone to break down organic compounds, including taste and odor compounds, organic micropollutants, pharmaceuticals, personal care products, and more, which can then be adsorbed and/or digested in the biofilter.
• Membrane filtration. Ultrafiltration (UF) membranes act as a pre-filter before the reverse osmosis (RO) process. This combination removes a great deal of total dissolved solids (TDS), as well as salts and other compounds that cannot
  be broken down chemically, including per- and polyfluoroalkyl substances (PFAS).
• UV advanced oxidation process (UV AOP). While the regulations only specify a UV component, UV AOP offers an additional barrier for substances that can
  survive O3-BAF and slip through membranes, such as 1,4-dioxane and in the case of San Diego, NDMA and 6-log virus

DPR Beyond California

California’s newest rules are sure to act as a template or starting point for many
states and municipalities. Still, changes are not going to come overnight. Since
IPR was included in Title 22, only a handful of states have begun exploring their own
recommendations and regulations for it, and fewer have actually implemented
them. Regulators have good reason to slow-walk the process; different communities have different levels of need, different senses of urgency, and different types of water composition. Any rules will need to account for these factors while also ensuring their requirements can meet federal and local drinking water standards.

A first step for each community would be to evaluate and fully understand the composition of the water entering the collection system and what each user is
potentially contributing to the shared water supply. Then the right disinfection
plan can be put into place based on this information as well as the standards set by
federal, state, and local authorities.

Pilot Or Demonstration Testing

Water utilities in California will need to design systems to meet the state’s new DPR standards, and the best way to do that is to begin with pilot or demonstration testing. San Diego Pure Water’s DPR system began as a small-scale pilot about 10 years ago. To date, the system has produced more than 1 million gallons of purified water, and more than 50,000 water quality tests have proven it meets all federal and state standards.

Pilot testing or demonstration facilities allow utilities to evaluate the performance
of one or more reuse technologies under conditions that closely resemble the actual operating environment. This helps operators identify potential challenges and optimize the treatment process before full-scale implementation. They can also be used to test how existing upstream processes interact with reuse technologies.

By working with a trusted partner, a utility can pilot one or more aspects of a DPR system. Some vendors offer trailer-based pilot systems. These systems are easy to
deliver, set up, and install. They also save space over skid-based systems. Pilot testing can help water utilities in California expedite the certification process. In other parts of the U.S., pilot testing can be used to develop DPR regulations or plan ahead for their implementation.

Regardless of the reason for the pilot test, it is critical that utilities take the time to collect as much data as possible before making a final determination. DPR has the potential to minimize the risks associated with water scarcity, creating more sustainable communities. California’s Title 22 regulations provide a valuable framework for addressing water scarcity, but successful adoption elsewhere will depend on careful pilot testing, data collection, and customization to local conditions, ensuring sustainable and resilient water solutions. For water utilities looking for help, Xylem can be your partner for pilot programs on your state’s regulation journey. We offer everything from remote access to full on-site pilot programs, as well as a range of technologies that can help meet California’s updated Title 22 and other regulatory standards.