Water Pressure Concerns

High Pressure

Higher than normal pressure is usually caused by one of two factors.

No Thermal Expansion Tank

The thermal expansion tank is normally located near the hot water heater.

Thermal Expansion Tank DiagramAn expansion tank is used as a safety device to allow for the expansion and contraction of water as it heats and cools in the water heater. As with any fluid, the water expands to a greater volume as it heats. A good example of this is a lid on a pot rising off as water in the pot reaches the boiling point. (Water does not have to boil to expand.). The expansion tank absorbs the expansion of the heated water molecules by using a bladder (or balloon) filled with air. Without a thermal expansion tank, the water pressure in a water heater could build to a very high level and cause leakage at the pressure relief valve (or pop-off valve) located on the water heater. Lime deposits could build up on a leaking pop-off valve and clog this safety device, which could then cause the water heater to explode. In addition, the lack of a thermal expansion tank allows higher than normal water pressure (caused by the heated water) to put stress on gaskets and fittings at faucets and commodes, which will then cause these fixtures to leak.

Faulty Pressure Regulator

More than likely, your home was constructed with a pressure regulator on the water service. In most cases, it is located where the water line enters the home - either in the basement or in the crawl space. However, some homes in the Warrenton Lakes area have pressure regulators located at the water meter, on the house side of the meter. When a pressure regulator fails, it will usually reduce the flow of water to a mere trickle. However, in rare cases, a faulty pressure regulator will open up and allow full line pressure to enter the home, which could cause damage to the home's plumbing system. Contact your plumber if you suspect problems with your pressure regulator.

Low Pressure

Water pressure varies within the Town's distribution system, from about 59 pounds per square inch (PSI) in the higher elevations of Town to around 159 psi in the lower elevations. The pressure variation is controlled by elevation, i.e. the higher the ground, the lower the pressure.

If you notice lower than normal pressure, please contact the Utilities Department at (540) 347-1858. Try to have the following information ready when you call:

  • How long have you experienced this problem?
  • Have you had any plumbing work done lately? (If you have, and the problem is isolated to a single faucet, check the aerator for debris).
  • Are you aware of any construction or emergency repair work in your area?                                                                                                                    **Low pressure could be caused by a faulty pressure regulator**