Recycled Water

 



The District is often asked how Vallejo citizens can conserve water by using graywater or recycled water. Graywater and recycled water are different, and are subject to different regulations.

Graywater

Graywater is untreated wastewater generated from bathroom sinks, showers, bathtubs, and washing machines. It does not include wastewater from kitchen sinks or dishwashers. By definition, graywater has not been contaminated by a toilet discharge, has not been affected by infectious, contaminated, or unhealthy body wastes, and does not represent a threat from contamination by unhealthful processing, manufacturing, or operating wastes.

Regulations concerning graywater can be found here.

Graywater is not treated, and is therefore not allowed to enter a storm drain. If a local resident or business uses graywater on their landscaping, the water cannot leave their property, either to a neighboring property or the street or storm drain. This would be a violation of the San Francisco Bay Regional Water Quality Control Board’s Municipal Regional Stormwater Permit.

If you are considering installing a graywater system, please make sure it is in permit compliance with the California Plumbing Code and Solano County’s Public and Environmental Health ordinances.

Recycled Water

There are currently three types of recycled water listed under Title 17 and Title 22 of the California Code of Regulations.

Disinfected Secondary: 2.2 Recycled Water

Wastewater that has been treated at secondary wastewater treatment facility, that has been oxidized and disinfected to reduce the median level of total coliform bacteria below a most probable number (MPN) of 2.2 per 100 milliliters. This water can be used for the surface irrigation of crops where the edible portion is produced above the ground and not contacted by the recycled water.

Disinfected Secondary: 23 Recycled Water

Wastewater that has been treated at secondary wastewater treatment facility, that has been oxidized and disinfected to reduce the median level of total coliform bacteria below a most probable number (MPN) of 23 per 100 milliliters. This water can be used for irrigation of non-crop vegetation such as cemeteries, restricted access golf courses, and freeway right of ways. It must be used at times and places where public access is limited.

Disinfected Tertiary Recycled Water

Wastewater that has been treated using a tertiary process to remove 99.999 percent of the plaque forming units of F-specific bacteriophage MS2, or polio virus, in the wastewater. This is also wastewater that has been oxidized and disinfected to reduce the median level of total coliform bacteria below a most probable number (MPN) of 2.2 per 100 milliliters, and the number of total coliform bacteria does not exceed an MPN of 23 per 100 milliliters in more than one sample in any 30 day period. The use of disinfected tertiary recycled water is almost unrestricted but must meet standards for turbidity. Otherwise, this water may be used for food crop production and unrestricted irrigation of parks, schools, residential landscaping and unrestricted golf courses.

Wastewater produced by the District is secondary treated wastewater with a coliform count of about 1000 MPN per 100 milliliter, which is greater than the restricted use groups. Modifications to the sewer plant to create tertiary recycled water were estimated at $11 million in the Reclaimed Water Study presented to the Board of Trustees June 2014. Distribution costs in the study were estimated at $26 million for a total project cost of $37 million.

The District is unable to distribute recycled water to Vallejo citizens at this time because we are unable to meet the standards for unrestricted use. VSFCD cannot distribute this to citizens as there is no way to control how the water is used and who or what would be exposed to it; this water is to be used for irrigation only but it could be easily misused for drinking purposes if proper handling could not be insured.

In May 2014, the District contacted with RMC to provide a Reclaimed Water Study. The results are available here.

How VSFCD Conserves Water

Here at the District, we are doing our part to conserve Vallejo’s precious water resources. We have turned off irrigation to outside landscaping and are able to use our treated wastewater to irrigate within the treatment plant, as well as to wash down tanks and road surfaces in private (not public) landscape areas, including a District-sponsored native plant nursery run by volunteers with the Wilson Jepson chapter of the California Native Plant Society.

All drains within the plant are channeled back into the treatment process. We have participated in a City of Vallejo Water Division water use survey. We regularly check for leaks, spikes, or other problems. Toilets are 1.6 gallon per flush (or lower). Faucets and showerheads have low flow aerators. Irrigation sprinklers are tested four times per year to ensure proper operation and coverage; broken or defective sprinkler heads are repaired or replaced as needed. Flush mechanisms in urinals have a 1 gallon (or lower) flush. Ice machines are air cooled, not water cooled. The washing machine is Energy Star certified. In our landscaping, all non-turf areas are mulched. Drip irrigation is used. Except in the front of the Administration building, all turf has been replaced with water-efficient shrubs or ground cover.