Graywater and recycled water
Graywater refers to untreated wastewater from washing machines, showers, bathtubs, or bathroom sinks that is used for outdoor irrigation. The wastewater can come from the washing machine, showers, bathtubs, or bathroom sinks. It may contain traces of soaps and detergents, but as long as these products are biodegradable/non-toxic, the water is a safe and effective water supply for most outdoor plants and lawns. Graywater differs from recycled water in the levels of contamination and necessary treatment the water goes through to be safe to reuse.
Graywater is not waste water from kitchen sinks, toilets or dishwashers.
Do not drink graywater.
There are many benefits to a graywater system in your home. Every time you do a load of laundry or take a shower, a graywater system can save water and reduce your utility bills. These systems are drought resilient and can help protect the longevity of your outdoor landscape during hotter summer months and dry periods. Additional benefits include reducing dependency on potable water, encouraging healthier soap/detergent choices, raising water use awareness, and protecting the urban watershed.
Residential graywater systems
In single-family homes, graywater can irrigate most outdoor plants, gardens and lawns, however, it cannot be used to irrigate root crops or edible fruits and vegetables that touch the soil. The best irrigation technique is a subsurface drip irrigation system where tubing is placed slightly below the ground.
Graywater systems can range from basic setups like putting down a bucket in the shower to collect water, to more complex systems installed throughout the entire house that include pumps, filters and treatment processes. The simpler the system, the more affordable and easier to maintain it will be. For the majority of households, a laundry-to-landscape graywater system is the best choice because these systems are exempt from permitting requirements in California and are relatively affordable in comparison to other graywater systems.
Laundry-to-landscape systems
A laundry to landscape graywater system is a simple process that automatically distributes graywater from the washing machine and distributes it to outdoor landscapes. It is relatively low cost and easy to install. On average, approximately 4,500 to 14,500 gallons of water are saved through a single laundry-to-landscape system each year. The washing machine’s internal pump slightly pressurizes the water, so this system can be used to irrigate flat ground or slightly sloped ground. In a typical system, the washing machine hose connects to a three-way valve to make it easy to switch between the graywater system and the regular sewer system.
For a step-by-step guide to installing a laundry-to-landscape system, refer to pages 19-25 of San Francisco Public Utilities Commission’s (SFPUC) Graywater Design Manual for Outdoor Irrigation(PDF, 3MB)
Laundry-to-landscape safe soaps and detergents
If you install a laundry-to-landscape system, it is important to select detergents and other cleaning products that have few to no harmful ingredients for landscapes. Specific ingredients to avoid include:
- Chlorine/bleach
- Peroxygen
- Sodium perborate
- Sodium trypochlorite
- Boron
- Borax
- Petroleum distillate
- Alkylbenzene
- “Whiteners”
- “Softeners”
- “Enzymatic” components
Use soaps and detergents that contain little to no chemicals and have biodegradable, non-toxic ingredients. Hydrogen peroxide bleaches can be used as an alternative to chlorine.
Recycled water
Recycled water refers to highly treated wastewater (including graywater) that meets California Code of Regulation standards. Similar to graywater, recycled water is primarily used for irrigation, but can also be repurposed for flushing toilets, used for decorative fountains, street cleaning, construction purposes and other non-potable water uses. Utilizing recycled water in these ways helps to reduce the need to use drinkable water for unnecessary purposes and promotes sustainability and water conservation. In addition, boosting water recycling in the Bay Area can have a secondary benefit, preventing red tides or algal blooms in the bay that threaten marine life. Wastewater disposed in large bodies of water can result in high amounts of nitrogen and phosphorous, which can drive the growth of algae blooms. By recapturing wastewater and repurposing it, it can help to prevent future algal blooms which can have devastating impacts on the Bay's ecosystem.
Recycled Water in Menlo Park
There have been multiple large and small scale recycled water projects within Menlo Park initiated by both the City and by external organizations. City regulations require that construction projects over a certain size use non-potable and/or recycled water or provide on-site water recycling to minimize the use of potable water.
Sharon Heights Project
In 2019, the West Bay Sanitary District installed a recycled water project in the Sharon Heights area to deliver recycled water to the Sharon Heights Golf & Country Club for irrigation. Learn more about the project by watching West Bay Sanitary’s Sharon Heights Recycled Water Facility Project Documentary. Visit West Bay Sanitary District's website to learn more.
Bayfront Recycled Water Project
West Bay Sanitary District provides wastewater collection services to Menlo Park, as well as to other surrounding communities. The wastewater collected from these areas flows to the Menlo Park Pump Station, located on Marsh Road near the entrance of Bedwell Bayfront Park, and is pumped to the wastewater treatment facility in Redwood City. Both the Menlo Park Pump Station and the wastewater treatment facility in Redwood City are operated by Silicon Valley Clean Water (SVCW). A substantial portion of the wastewater treated at the SVCW facility is discharged to the San Francisco Bay, while the remainder is treated to recycled water standards and sold to Redwood City customers for non-potable uses. The Bayfront Recycled Water project is proposed to build levees around the Marsh Road Flow Equalization Facility to protect it from sea level rise and storm surge and to build a Recycled Water Facility on this site to serve the Bayfront area of Menlo Park.
Additional measures
Menlo Park collaborates West Bay Sanitary District to install recycled water pipeline infrastructure when roads are repaved to minimize disruption from future construction needs. Additionally, some new commercial buildings in Menlo Park have installed dual-plumbing in their buildings to recapture recycled water for toilet flushing.
FAQs
How much does a laundry-to-landscape system cost?
The cost to install a laundry to landscape system will vary depending on landscape size and who will install the system. A large part of the work involves digging mulch basins and trenches to bury pipes. To save on cost, you can do the installation on your own. The cost of materials for this project can range between $100-$300 and the cost of hiring a professional to perform the installation can range between $700 to $2,000.
Does Menlo Park offer a rebate for the installation of graywater systems?
The City of Menlo Park does not currently offer any rebates and incentives for graywater systems. However, Menlo Park Municipal Water customers are eligible for a variety of other rebates incentives for water saving landscape projects such as the Lawn Be Gone program which provides $3 per square foot of lawn converted to drought tolerant landscape, rain barrel rebates, and rebates for purchasing and installing irrigation hardware such as smart controllers and other equipment.
Visit menlopark.gov/waterrebates to learn more
Will a laundry to landscape system hurt my washing machine?
A properly installed system should not cause your washing machine any additional wear and tear. Consider the following recommendations when installing your laundry-to-landscape system:
- If there are existing issues with your washing machine, replace your washing machine before installing a graywater system
- If your landscape is uphill from your washing machine you will need to install an additional pump
- Do not have the water travel more than 50 feet across flat yard as it adds strain to the pump
- Use 1” tubing on the main line
Can I install a graywater system throughout the entire house?
Large scale household graywater projects with complicated systems that require a multitude of pumps, filters, plumbing, maintenance considerations and permit requirements are not viable for the majority of households.
Menlo Park Municipal Water recommends that its customers start simple by using a bucket to collect “warming-up” shower water to refill the back of their toilet and irrigate their plants. The best graywater system to install is a laundry-to-landscape system due to its low cost, lack of permit requirement and relatively easy installation.
How can I collect graywater from my shower, bath or bathroom sink?
The most cost effective way to collect and reuse water from your shower, bathtub or bathroom sink is to physically collect it with a bucket and repurpose it appropriately.
Which plants can I water with graywater?
Larger plants are better suited for graywater irrigation systems because it can be difficult to pump water to many small plants spread out across a large area. Drought tolerant plants are also a great pairing with graywater systems since they do not require large amounts of water.
Check out Menlo Park’s Top Pick Plant List(PDF, 1016KB) for drought tolerant planting.
How do I protect the environment while using graywater?
The two key rules to adhere to for environmentally conscious graywater reuse are:
- Do not use toxic products when using the washing machine
- Do not allow graywater to enter a freshwater source like creeks, rivers or high groundwater tables.
How is recycled water treated?
There are different types of recycled water based on the amount of treatment it passes through. The State Water Board regulates how recycled water can be used based on the level of treatment. Recycled wastewater undergoes primary, secondary and sometimes tertiary treatment. In the initial phase of treatment, sizable particles are eliminated. In the secondary stage, bacteria is utilized to eliminate roughly 90% to 95% of the remaining particles, while a disinfectant like chlorine is employed to eradicate bacteria, viruses, and other harmful microorganisms. In certain cases, advanced tertiary treatment methods like filtration or reverse osmosis are required. These treatment procedures imitate and expedite the natural purification processes found in nature and make the treated water safe for appropriate reuse.
Where can I get recycled water?
In the City of Menlo Park, West Bay Sanitary District is the purveyor of recycled water. Contact them directly at (650)-321-0384. You may be eligible to participate in Redwood City’s recycled water fill stations. Visit their website to learn more.