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Did you know that your water meter was sized for the property at the time it was built? 

When buildings and other facilities are built, plans are submitted to SJW’s Engineering Department.  We evaluate the plans and determine the appropriate meter size based on current California Uniform Plumbing Codes and the latest American Water Works Association (AWWA) standards in place at that time.

From time to time, we do receive customer requests to downsize the meter. 

What determines the meter size?

Determining the right meter size for a property involves several considerations. 

  1. The flow rate of each water-using fixture (faucet, toilet, shower, washing machine, dishwasher, etc.) in the residence or business.
  2. Pressure, water velocity, and total number of water-using fixtures to meet industry standards including:
    • Minimum residual pressure of 35 psi at the meter
    • Velocity of water does not exceed 13 feet per second in service line from main to meter

SJW and the California Public Utilities Commission (CPUC) want to make sure you have adequate pressure and flow rate for your property.

Why is the pressure and flow rate for the property important?

Keeping the speed of water under control helps to minimize water hammer, the chatter and noise from household water valves, and damage to water fixtures and appliances such as water heaters, clothes washers, and dishwashers which can be costly to repair or replace and can cause further property damage. 

Which things are not considered in a meter downsize request?
  1. Water usage levels
  2. Number of residents
  3. Change in irrigation

Please note that services are sized based on the larger flow of maximum domestic demand or fire sprinkler flow (if applicable) plus 5 gallons per minute domestic flow for residences excluding outdoor irrigation. In most cases, a severe reduction or elimination of irrigation use would not make a difference in service size.  

Do plumbing codes and standards change over time?

Yes, they do! In fact, most current standards require larger meters than had been previously required under older regulations. For example, a 25-year old house with a 3/4-inch meter would most likely be issued a 1-inch meter based on current standards.