Water Pressure

What's Normal?

The normal pressure for your property will depend on how close you are to your water supply source (tank, well, or reservoir from which your water comes). If your home is at a higher elevation relative to a tank’s location, you will have lower pressure. The lower your home is located downhill from the tank, the higher the pressure (approximately ½ PSI per foot).

Water pressures in flatland areas are based on reservoir water levels, assisted by the use of booster pumps.

High Pressure

Unsure if you are experiencing high pressure? Here are some "symptoms:"

  • "Clanging" or "rattling" pipes may occur when a faucet, dishwasher or washing machine shuts off. This is caused by a high-pressure water hammer.
  • Water heater pressure relief valve malfunctions.
  • Reoccurring leaks.

What you can do:

  • New homes may need to have a pressure reducing valve (regulator) installed according to local uniform plumbing code.
  • Existing homes experiencing high pressure may have a malfunctioning regulator.

Hint: If your house has particularly high water pressure, you may want to turn off the water supply to appliances such as dishwashers and washing machines when you go on vacation. This may prevent water damage caused by a ruptured supply hose. You might also want to turn off your house shutoff valve. However, if you do this, you may not have water for your irrigation system.

Low Pressure

If your house is located in a low-pressure area (in the hills or very near to the tank that serves your home) the only way of increasing pressure is to install a booster system. In the event you experience sudden drops in pressure, we recommend you investigate the following possibilities:

  • leaking water mains (utility's responsibility)
  • leaking service line between meter and house (customer's responsibility)
  • water meter valve shut off
  • customer's house valve shut off
  • customer's water softener malfunctioning (use by-pass feature)
  • pressure regulator malfunctioning (customer's responsibility)

Normal adequate water pressure decreasing slowly, over an extended period.

Potential problems/causes:

  • reduced water flow/volume due to deteriorating galvanized service line between meter and house. the service line is on customer property and is considered part of the customer's maintenance responsibilities along with other pipes and water systems in the home.
  • intermittent pressure regulator malfunction
  • plugged faucet aerators (screens)

If you are unable to determine the problem or whose responsibility it is to repair, please call our Customer Service department at (408) 279-7900. Our service representative will be happy to assist you.

Pressure Regulators

You can determine your static water pressure by attaching a water-pressure gauge to an outside hose bib (static pressure is measured while no water is being used on the property).

Installing a pressure-reducing valve (pressure regulator) can reduce water pressure to a desirable range of 50 to 60 PSI for inside use. To keep the desirable higher pressure for outdoor hose bibs and sprinkler use, install the pressure regulator downstream from them. The regulator is installed and maintained by the customer.

Although the regulator is the homeowner's responsibility to install and maintain, we can assist in determining if your regulator has malfunctioned. Please call our Customer Service department at (408) 279-7900. Our Customer Service Representatives will be happy to assist you.