Water Pressure

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The normal pressure for your property will depend on its physical relation to the water source supply (tanks and reservoirs). If your home is at a higher elevation relative to a tank’s location, you will have lower pressure. Conversely, 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:
  • New homes may be required to have a pressure reducing valve (regulator) installed according to local uniform plumbing code.
  • Existing homes experiencing high pressure may have a malfunctioning regulator.

You may notice symptoms of high pressure:

  • "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.

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 (i.e., in the hills, near a water utility's tank), 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 slowly, over time decreases.

Potential problems/causes:

  • reduced water flow/volume due to deteriorating galvanized service line between meter and house (customer's responsibility)
  • 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.