Understanding California Title 22 Rules for Recycled Water Use
Operators across the water sector in New South Wales, Victoria, and Queensland often look overseas when local councils ask whether their treatment trains are strict enough. California's Title 22 regulations are frequently held up as a benchmark, partly because the state has been producing and reusing recycled water at industrial scale for decades. While the rules are American, the engineering questions are universal: how clean does reclaimed water need to be before it touches a park, a school oval, or a cooling tower.
For Australian utilities that already meet the Australian Guidelines for Water Recycling, the California approach offers a useful case study in how quality grades, monitoring frequencies, and cross-connection controls can be packaged into a single regulatory framework. Engineers, consultants, and plant operators attending sessions hosted by LABS of CWEA will recognise many of the technical tensions: how to balance public health protection with the cost of advanced treatment, and how to communicate those trade-offs to a sceptical community.
The scope and origins of Title 22
Title 22 is a section of the California Code of Regulations administered by the State Water Resources Control Board, and it sets the rules for what can be called "recycled water" in the state. It sits within a broader California push to reduce reliance on imported supplies, a drive that gathered pace during the 1970s and 1980s droughts and has accelerated since. The framework covers everything from the source of the wastewater through to the end use, and it applies whether the water is produced by a small satellite plant in a rural town or a major inland utility serving millions.
The regulations divide responsibility between the regulator and the producer. The state sets the water quality criteria and the allowed uses, while the local wastewater agency must obtain a permit, install the right level of treatment, monitor the results, and report back. Title 22 also requires a recycling coordinator to be appointed at each producing facility, and it mandates cross-connection inspections and backflow prevention on every customer site. These requirements are not optional add-ons; failure to comply can shut down a producer's permit.
The four quality grades
The heart of Title 22 is a tiered classification system that sorts recycled water into four broad categories based on treatment level and intended use. The grades run from disinfected tertiary, suitable for irrigation of food crops and parks, through disinfected secondary, which can be used for pasture and fodder, down to undisinfected secondary, which is restricted to restricted-access sites like cemeteries and construction.
For Australian practitioners, the mental model is similar to the Australian Guidelines for Water Recycling, which classify recycled water for schemes ranging from dual-pipe urban irrigation in Melbourne to Class A+ schemes in South East Queensland. The California twist is that the grades are tied directly to specific treatment processes rather than purely to water quality numbers. Disinfected tertiary recycled water, for example, must pass through filtration as well as disinfection, with defined log-reduction targets for viruses.
This process-based approach appeals to regulators because it is auditable. A plant operator can demonstrate compliance by showing that the filters are in place and operating within specification, rather than relying solely on routine sampling. For utilities in Perth and Adelaide where the Water Corporation and SA Water operate extensive recycling schemes, this kind of clarity is often cited as a model when local guidelines are reviewed.
Monitoring, verification, and operational discipline
Title 22 is unusually explicit about how often monitoring must happen and what records must be kept. Producers typically log turbidity continuously from each filter, monitor disinfectant residual at defined points, and run regular coliform sampling on the finished product. The regulations also prescribe what to do if a result falls outside the allowed range, including notification timelines and corrective action steps.
This operational discipline has implications for staff training and shift coverage. Many Australian plants, particularly regional councils servicing towns across the Murray-Darling Basin, have found that adopting a Title 22-style monitoring regime requires investment in online instrumentation and a clear chain of responsibility. Utilities that have toured Californian facilities often return with a sharper sense of how much paperwork sits behind a compliant recycled water scheme.
Cross-connection control is another area where the California rules are stricter than what is commonly required elsewhere. Every customer receiving recycled water must have an approved backflow device, a signposted meter, and a periodic inspection. While this adds cost, it has become a selling point in communities where recycled water has faced political resistance.
How Title 22 compares with Australian frameworks
Both California and Australia treat public health as the primary constraint on recycled water use, but they organise the rules differently. Title 22 lives in a single regulatory chapter and is enforced by a state agency, whereas Australian schemes typically sit across multiple instruments: state legislation, utility operating licences, and the Australian Guidelines for Water Recycling endorsed by the Natural Resource Management Ministerial Council.
The table below summarises where the two systems overlap and where they diverge.
| Aspect | California Title 22 | Australian Guidelines for Water Recycling |
|---|---|---|
| Regulatory home | California Code of Regulations, administered by the State Water Resources Control Board | Endorsed framework applied through state legislation and utility licences |
| Quality classification | Four grades tied to specified treatment processes | Multiple classes (A+, A, B, C, D) tied to end use and log-reduction targets |
| Typical end uses | Irrigation, industrial cooling, toilet flushing, groundwater recharge | Irrigation, industrial use, drinking water augmentation pilots, dual reticulation |
| Monitoring approach | Continuous online monitoring with prescribed frequencies and triggers | Risk-based monitoring plans, often with utility-specific targets |
| Cross-connection control | Mandatory device, signage, and inspection at every customer site | Required by state plumbing code but inspection frequency varies |
For practitioners used to the Australian risk-managed approach, the California system can feel both more prescriptive and easier to defend when an incident occurs.
Practical lessons for water utilities and operators
The most transferable lesson from Title 22 is the value of writing down who is responsible for what. Australian schemes that have struggled with incidents often trace the problem back to an ambiguous handover between the producer, the distributor, and the customer. The California approach forces a recycling coordinator to be named, with explicit duties, and that single change has been credited with improving response times when results fail.
Another lesson is the importance of investing in continuous online monitoring rather than relying on grab samples. Turbidity meters on filters, chlorine residual analysers on the distribution main, and flow-paced sampling have all become cheaper and more reliable. Utilities in Geelong and on the Mornington Peninsula have used similar instrumentation to satisfy both their state regulators and the local councils that host their schemes.
Engineers preparing for the next round of facility tours and technical workshops can review upcoming technical events to see where these topics will be explored in person, often with site visits that make the regulatory language far more concrete.
The practical takeaway is straightforward: study Title 22 not to copy it, but to pressure-test your own framework. A scheme that can answer the same questions California asks, who is responsible, how clean is clean enough, and how do you know, is probably in good shape. Where those answers are unclear, that gap is where the next upgrade should be planned.