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.

The water pressure in your building may differ from the water pressure at your meter depending on their relative elevations and other items that you may have installed on your property (like irrigation systems). For example, if your home sits uphill from the water meter, your water pressure will be lower in your home than at the meter.  SJW is responsible for pressure at the water meter. Customers are responsible for the parts of their water system that are on their property beyond the water meter. Visit our “Who’s Responsible for What?” page  for more information.

who's responsible

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 malfunction (such as leaking or otherwise not functioning properly).
  • Reoccurring leaks.

What to Consider

  • New homes may need to have a pressure regulator installed according to local California Plumbing Code.
  • Existing homes experiencing high pressure may have a malfunctioning pressure regulator.

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 to repair)
  • Leaking service line between meter and house (customer's responsibility to repair)
  • Water meter valve shut off
  • Customer’s house valve shut off
  • Customer’s water softener malfunction (most water softeners have a by-pass feature which allows you to divert water around the water softener and directly into your building until the malfunction is addressed)
  • Customer-side pressure regulator malfunction (customer's responsibility)

My Pressure Has Been Decreasing Slowly

If your normal adequate water pressure has been decreasing slowly, over an extended period, here are some potential causes to consider. 

Potential Causes

  • Reduced water flow/volume may be 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.

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 regulator (also known as a pressure-reducing valve) 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.

Pressure Changes at Your Service

SJW is continually updating its distribution system to provide customers with high quality water and reliable service. In order to increase system reliability, SJW will sometimes make system changes that can result in a change in the water pressure at your service connection. This is relatively uncommon. If this happens, you’ll receive a letter notifying you in advance of the change. If you receive a letter notifying you of a pressure change, know that it will not impact the amount of water you can use. 

Pressure Decrease

If you have received a letter notifying you of a pressure decrease at your property, in order to use the same amount of water you may need to more fully open your faucet, hose bib, valve, etc. If you have an existing pressure regulator, irrigation, or fire suppression system that depends on a set water pressure, it may need to be adjusted based on the new reduced pressure at your service connection.

We recommend you consult a licensed professional for any adjustments to your household pressure regulator or fire sprinkler system. Any adjustments, leaks, or repairs on the customer’s side of the service as a result of the reduction in water pressure is the property owner’s sole responsibility. 

Pressure Increase

If you have an existing fire suppression or irrigation system that depends on a set water pressure, it may need to be adjusted based on the new increased pressure at your service connection. If the new increased water pressure is above 80 psi, you may want to consult with a licensed plumbing contractor to determine if installation of a pressure regulator is necessary at your property.

For new buildings where the water pressure is above 80 psi, the installation of a pressure regulator is required by the California Plumbing Code. This is not required at an existing property, but a plumber would be able to help you determine if it would be recommended for your setup.

Any adjustments, leaks, or repairs on the customer’s side of the service as a result of the increase in water pressure is the property owner’s sole responsibility.

Category
Water Quality