- Public Works
- Water Quality
Water Quality Facts
The City of San Bruno is proud to produce high quality water that continues to meet and exceed all federal and state standard for safe drinking water. The Water Division feels it is important to answer all questions that our customers may have regarding drinking water. The following fact sheets have been compiled to answer many of our customers commonly asked questions.
Water Supply and Quality
The City of San Bruno utilizes ground water and surface water to supply domestic water to over 11,000 service connections through approximately 116 miles of water mains. Groundwater is produced locally from its groundwater wells. Surface water is predominantly supplied from runoff and snowmelt from the Sierra Nevada delivered through the Hetch Hetchy aqueducts. San Bruno’s surface water is treated at the Harry Tracy Water Treatment Plant which is owned and operated by the San Francisco Public Utility Commission (SFPUC). San Bruno residents receive a blend of surface and groundwater from these sources.
The City's wells supply over 2 million gallons daily. Historically, approximately half of the City’s total water supply is derived from purchased surface water from the SFPUC and the groundwater that is produced from the City’s wells.
Water is stored at multiple storage tanks located throughout the City to supply peak demands as well provide adequate fire protection for the community.
If you have other questions, please call the Water Division at 650-616-7160.
- Keeping Your Water Safe
- Water Characteristics
- Water Pressure
- Water Pressure - High
- Water Pressure - Low
At the SFPUC Water Treatment Plant and well sites, chemicals are added to water for the purpose of disinfection. Effective February 2004, the City converted from Chlorine to Chloramines as the primary water disinfectant. Chloramines are a combination of chlorine and ammonia. The conversion to Chloramines has allowed the City to increase protection of public health, while meeting stricter state and federal water quality regulations. Chloramine is more stable than chlorine and will last longer in the distribution system, providing increased protection from bacterial contamination and improving taste and odor.
To comply with state and federal law, Water Distribution and Treatment Operators must possess and maintain valid California State Water Resource Control Board certification in water treatment and distribution. Our operators and technicians obtain state certification of various grade levels (I-V) through a combination of course work in water science, years of work experience and successfully passing a state administered Water Treatment or Distribution Operator examination. Our certified employees operate, monitor, maintain and regulate the pump stations, wells and tanks that make up your water system 24 hours a day, 7 days a week, to ensure the water meets and exceeds all state and federal standards for drinking water.
Each area's natural waters have distinctive characteristics related to the dissolved minerals of the local geology. Most water treatment plants do not alter the water's mineral characteristics. All water tastes different because the nature of the materials that form the earth's crust affect not only the quantity of water that may be recovered, but also its chemical makeup. As surface water infiltrates and percolates downward to the water table, it dissolves some of the minerals contained in soils and rocks. Groundwater, therefore, sometimes contains more dissolved minerals than surface water. All drinking water must meet the state and federal requirements, and the City's water continues to meet and exceed these standards.
Operating water pressure within the City's distribution system can range from about 30 psi to 130 psi. Pressure within the system varies depending on the elevation of your property in relation to the elevation of the reservoir that provides water service for your area. Peak water use and routine water system operations also can cause water pressure in the distribution system to fluctuate. Other variables that may affect water pressure include water softeners, plumbing restrictions, point of use treatment devices (cartridge filters, etc.) and seasonal water demands.
The City cannot adjust the water pressure for specific properties; however, if you have concerns with high pressure or low pressure, there are some steps you can take that may help resolve the issue.
Most home improvement stores sell inexpensive water pressure gauges that can be simply attached to your outside faucet or hose bib. This will be useful when trying to determine the on-site water pressure at your property.
You may need a pressure reducing valve ("PRV") if your water pressure is more than 80 pounds per square inch ("psi"). If the water pressure at your property is 80 psi or greater, a PRV will help decrease the water pressure. In accordance with Uniform Plumbing Codes, property owners and/or customers are responsible for installing and maintaining their own individual PRV devices whenever static water pressure exceeds 80 psi.
PRVs will not increase water pressure to a property; however, they do serve as a critical component to decrease water pressure to your level of preference. Most plumbing professionals recommend a PRV setting between 35 and 60 psi. Sustained pressure that exceeds 80 psi can damage on-site plumbing systems and may affect your water fixtures. PRVs should be installed on the customer's side of the water meter and are usually located near the water heater, water softener or on the inlet water line between your home and the water meter.
Decreased water pressure usually denotes a plumbing problem. If you're experiencing a decrease in water pressure at your property, the issue is typically within your plumbing system. The list below may help you identify the cause of the low pressure at your property.
- Water Softeners - In many cases, the cause of a sudden change or decrease in home water pressure is the result of a water softener. If it has been a while since your water softener was serviced, you may want to consider having a professional service technician evaluate your water softener’s condition. Depending on the type of water softener and plumbing configuration, you may be able to troubleshoot low-pressure issues caused by your water softener. One option is to temporarily put the softener in bypass mode to see if pressure increases. If it does, the low pressure is probably caused by the water softener and it may need to be serviced or possibly replaced
- Pressure Reducing Valve ("PRV") - If the low pressure is at every faucet in the home and you have a PRV installed on your home plumbing system, you may want to verify that your PRV is set appropriately. Most PRVs are bell-shaped devices that may be installed outside on the inlet water line between your home and water meter. PRVs should be adjusted by a licensed plumber.
- Clogged Aerators - If the low pressure is not affecting every faucet, the problem may just be a clogged or blocked faucet aerator. Check the aerator screens for rust, debris, scale or other particles that may be restricting flow. Simply clean or replace the aerator altogether.
- Hot Water, Low Pressure - If the low pressure is only affecting the hot water at your property, there could be a problem with your water heater. Check the shut-off valve near the water heater and make sure it is fully open. You may need to consult a licensed plumber to evaluate the condition of your water heater and determine if it is affecting your water pressure.
- House Water - Most homes have a house water valve located near other outside hose bib. The valve may also be located in the garage or on the inlet line between your home and water meter. This valve, which may be utilized to make plumbing repairs, allows you to shut off the flow of water to the home. Make certain that this valve is open completely; even the slightest closure can restrict flows and decrease the water pressure.
- Residential Leak - Low pressure also can be caused by a water leak somewhere on the property.