Water Pressure Definition

Pumping and gravity build the water pressure at your faucets.

The term "water pressure" describes the flow strength of water through plumbing pipes, measured in pounds per square inch (psi). You need to maintain pressure sufficient to keep water flowing to all parts of the system even when there's heavy demand for water. Water systems maintain pressure by pumping and gravity.

Pumping

Household well water systems and big city waterworks use pumps to supply water pressure, according to the National Ground Water Association's website. Household well water systems include a pressure tank holding several gallons of water under compressed air as a reserve to meet small demands such as filling a coffeepot or glass. This means the household pump only goes on when there's large water demand.

Gravity

Municipal water systems in small and medium cities rely on gravity to maintain pressure on all their lines. These municipal systems use pumps to push water up into a tall tower, according to the technology education website of the University of Illinois. Water is heavy so the weight of the water in the tall tower applies pressure to the entire water system. That pressure pushes water out of your tap at a reasonable rate.

Pressure Problems

Ideally, water pressure at your taps should be around 80 psi, but municipal water systems may have pressures of up to 175 psi, according to the San Antonio Water System website. If you are having problems with high pressure, you can install a pressure reducing valve on your side of the water meter. But if pressure at your taps is far below 80 psi, you should check for clogs or restrictions at your faucet aerators, bad faucet valves, a malfunctioning water heater or water softener, a partially closed supply valve, weak pump and plumbing leaks.

References

• National Ground Water Association: Water Pressure
• University of Illinois: Gravity & Water Pressure
• San Antonio Water System: Water Pressure