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Monte Vista Water District provides retail and wholesale water service to 130,000 residents in the communities of Montclair, Chino Hills, and portions of Chino.

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Fixing a Leak Employee fixing a meter leak

Water Pressure


MVWD Pressure Zones
(click image to enlarge)

The water distribution system is divided into four (4) pressure zones. A pressure zone is an area of service supplied by a source or a number of sources that provides a constant hydraulic gradient. Typically, the hydraulic gradient is provided by the high water level of the reservoir serving the pressure zone. For pressure zones with no gravity storage, the hydraulic gradient may be provided by pumping and reducing in a direct-pressure principle of operation or solely by pressure reducing.

  • Zone 1
    • The northernmost pressure zone
    • Supplied by wells in the area, Water Facilities Authority through hydrogenerator #1 and booster pump stations at 4 plants.
    • Three reservoirs provide gravity storage.
  • Zone 2
    • The second northernmost pressure zone
    • Supplied by one well and a pump station
    • Two reservoirs provide gravity storage
    • Water is boosted from this zone to Zone 1
    • Water is pressure reduced to Zone 3
  • Zone 3
    • Supplied by 5 wells
    • Fed by Zone 2 through pressure reducing valves
    • Additional supply can be provided as needed from the Benson Feeder through a pressure reducing valve
    • One reservoir provides gravity storage
    • Water is boosted from this zone to Zones 1 and 2
    • Water is pressure reduced to Zone 4
  • Zone 4
    • No direct source of supply in this zone
    • Relies on Zone 3 for supply through 4 active pressure reducing stations

Low Water Pressure

Common causes of low water pressure are incorrectly adjusted valves, a water leak, or use of water during peak demand times. If you experience low water pressure, use these troubleshooting tips to help restore your normal water pressure.

  • Check Your House Valve: Your house valve is usually located at the hose bib. Adjust the house valve counter clockwise to ensure the valve is fully open. When the valve is in the "on" position it will be parallel with the hose bib. If the house valve is in the "off" position (pointing away from the hose bib) water flow to your home will be restricted. If your house valve is a wheel valve, turn counter clockwise to open and clockwise to close.
  • Check Your Customer Valve: Your customer valve is located in your meter box on the side closest to your home. This valve looks like a handle and should turn easily by hand. Make sure the customer valve is fully open by turning the handle counter clockwise. The handle is parallel with the meter when it is in the "on" position.
  • Check Your Pressure Regulator: Sometimes pressure regulators need to be adjusted or serviced to restore normal water pressure to your home. Pressure regulators should be adjusted carefully. Incorrectly adjusting the regulator can result in water pressure that is too high or too low. Water pressure that is too high can cause some household appliances to malfunction. It is recommended that a qualified plumber make adjustments or repairs to your regulator.
  • Do You have a Water Softener? Customers may notice a decrease in the water pressure after having their water softener serviced. Please check to make sure the service person fully reopened the valve when the service or repairs were completed.
  • Check for Mineral Deposits: If you are experiencing low pressure from one of the faucets in your home it may be due to mineral deposits. Mineral deposits from hard water can clog the aerators on faucets and shower heads. You can restore the water pressure by cleaning the aerators.

If your water pressure is still low after troubleshooting these areas, contact the District at (909) 624-0035.

High Water Pressure

The District's service area is divided into four pressure zones. Whenever possible water storage tanks (reservoirs) are located at a higher elevation than the area it serves so water can flow by gravity. Homes that are at the lowest elevation from the reservoir will have higher pressure. In higher pressure areas customers can adjust or install a pressure regulator to reduce the water pressure coming into their home. If your water pressure is high, your pressure regulator may need to be adjusted or serviced. It is recommended that a qualified plumber make adjustments to your pressure regulator since incorrectly adjusting the pressure regulator can affect household appliances.

Do I Have a Pressure Regulator?

Many homes are equipped with a pressure regulator. Pressure regulators are bell shaped devices that are usually located on the inlet pipe next to your hose bib and house valve. Pressure regulators are used to adjust the water pressure to an appropriate pressure for your home. Pressure regulators cannot increase the pressure beyond the maximum pounds per square inch (psi) supplied by the District in your area.