Yes, there are different types of recycled water based on the level of treatment the water has gone through. The state regulates how recycled water can be used based on the level of treatment.
Recycled wastewater undergoes primary, secondary and tertiary treatment. During primary treatment, large solids are removed. Secondary treatment uses bacteria to remove approximately 90% to 95% of the remaining solids and uses a disinfectant, such as chlorine, to destroy bacteria, viruses, and other pathogens. For some reuse applications, advanced tertiary treatment processes, such as filtration or reverse osmosis, are required. The treatment processes duplicate and accelerate nature’s own purifying actions.
Tertiary treated recycled water, often called Title 22 water, can be used for a wide variety of non-potable uses including all types of irrigation, toilet flushing, and industrial processes. The City of Redwood City produces and distributes disinfected, tertiary treated recycled water.
How will I know if a site is being watered with recycled water?
Sites using recycled water will be clearly marked with appropriate signage.
Is recycled water available in my area?
A direct connection to Redwood City's recycled water system is available to sites east of US 101. The City is working to bring recycled water pipes across US 101 to service the main City.
If you are interested in retrofitting your site for recycled water use, please contact the Public Works Department by calling (650) 780-7464 or emailing firstname.lastname@example.org.
Is recycled water different from gray water?
Yes. Recycled water is wastewater treated to approved levels for reuse for approved non-potable uses which are primarily landscape irrigation but can include industrial applications such as cooling tower make-up water. Graywater is defined in the California Water Code as “…untreated wastewater which has not been contaminated by any toilet discharge has not been affected by infectious, contaminated, or unhealthy bodily wastes, and which does not present a threat from contamination by unhealthful processing, manufacturing, or operating wastes. Graywater includes wastewater from bathtubs, showers, bathroom washbasins, clothes washing machines, and laundry tubs but does not include wastewater from kitchen sinks or dishwashers.”
Graywater can only be used to irrigate landscaping at the site from which the graywater is generated and can only be done using a subsurface irrigation system.
Is recycled water regulated?
Yes. There are a variety of laws, regulations and statewide policies that govern how recycled water is defined, what it can be used for, and under what conditions in the State of California. Title 22 of the California Code of Regulations describes the treatment requirements for recycled water as well as the approved uses based on the level of treatment. Also included in Title 22 are the use area requirements which describe restrictions on its use and the requirement to notify the public through signage that a site is using recycled water. Title 17 of the California Code of Regulations describes the requirements for backflow prevention devices required at a site when recycled water is being used. This is to prevent recycled water from getting into the public drinking water system in the event a cross-connection occurs at a site where recycled water is used. Silicon Valley Clean Water and Redwood City also extensively monitor, test, and report on the recycled water produced and distributed for use.
Is recycled water safe for children playing in parks?
Redwood City's recycled water is approved for irrigation purposes. In over 80 years of recycled water use in California, there have been no documented cases of any ill effects from proper use. Incidental contact with recycled water, such as walking on grass after it has been watered, is safe for adults, children and pets.
Is recycled water safe to drink?
Although recycled water is treated to a high standard that meets State regulations, tertiary treated recycled water is not approved for drinking purposes. However, if you accidentally drink some recycled water do not panic. Recycled water undergoes an intensive filtration and disinfection process. Just like accidentally drinking water from a pool, a person may ingest some recycled water without experiencing adverse health effects. If you experience any negative symptoms, call your doctor.
For pets: There is no harmful effect if and when your dog or cat drinks from a recycled water puddle, just like when they drink water running down a gutter in the street. Recycled water is safer than water form a ditch or pond. However, it is not recommended to give your pet recycled water to drink.
What is recycled water used for?
The State has identified approved uses for recycled water in California based on the level of treatment. Redwood City produces and distributes disinfected, tertiary treated recycled water. This water can be used for a wide variety of non-potable uses such as landscape irrigation, toilet flushing and cooling towers in commercial buildings, and industrial processes such as carpet dyeing, concrete production and composting. However, this water is not approved for drinking. Every gallon of recycled water used for these purposes saves a gallon of drinking water.
What is recycled water?
Recycled water is defined in the California Water Code as “…water which, as a result of treatment of waste, is suitable for a direct beneficial use or a controlled use that would not otherwise occur and is therefore considered a valuable resource. Basically, recycled water is highly treated wastewater that is reused for purposes such as agricultural and landscape irrigation, industrial processes, toilet flushing, or replenishing groundwater basins. Redwood City's wastewater is treated and processed by Silicon Valley Clean Water (SVCW) in southeastern Redwood Shores.
What plants should I use with recycled water?
It is important to know that not all plants perform well when irrigated with recycled water. Before designing or retrofitting your landscape is it good to understand which plant species perform best with recycled water, and how soil conditions and irrigation practices will also affect plant health. Redwood City has developed a list of recommended plants for use with recycled water. For more information please refer to this document about Maintaining Plant and Soil Health when using recycled water.
Who develops the health standards for recycled water?
The State Water Resources Control Board's Division of Drinking Water establishes and enforces standards for recycled water use.