Did You Know?

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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Repairing a Meter Employee repairing a meter

Frequently Asked Questions

Cross-Connection/Backflow

  • What causes backflow?

    What causes backflow?

    Backflow is possible in two situations, backsiphonage and backpressure. Backsiphonage occurs when there is a sudden reduction in the water pressure in the distribution system, such as during firefighting or when a water main breaks, water flow can be reversed. This can create a suction effect drawing the non potable substance into the potable water system. Backpressure is created when pressure in non-potable system, such as in a recirculation system containing soap, acid or antifreeze, exceeds that in the potable system pressure. This can force the potable water to reverse its direction of flow through the cross connection. Non-potable substances can then enter the potable water system.

  • What is a cross connection?

    What is a cross connection?

    A cross connection is a permanent or temporary connection between potable drinking water and anything that can pollute or contaminate the water supply.

  • What is backflow?

    What is backflow?

    Water distribution systems are designed to keep the water flowing from the distribution system to our customer. However, when hydraulic conditions within the system deviate from the "normal" conditions, water flow can be reversed. When this backflow happens, contaminated water can enter the distribution system.

  • What is cross connection control?

    What is cross connection control?

    Cross connection control is a program designed to ensure safeguards are in place to protect our water supply. Through education and cooperation among the public and water providers, we can continue to provide high quality drinking water.