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Diagnosing and dealing with low household water pressure

This gauge shows how much pressure is in the system, but clogs can cut pressure to showers and faucets.
This gauge shows how much pressure is in the system, but clogs can cut pressure to showers and faucets.
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By Tim Carter
Saturday, January 22, 2011

DEAR TIM: I've got low water pressure in my house. Is there any way to improve it? My neighbors all seem to have much better pressure, and we're all on the same city water main out at the street. I also have this problem at a summer cabin where the water is supplied by a well. What are the main causes of poor water pressure? How can they be fixed? - Frankie S., Kingston, Rhode Island

DEAR FRANKIE: You did the right thing by checking to see if low water pressure is prevalent in your neighborhood. I know many city locations where water pressure is low in every house on adjacent streets. As crazy as this sounds, you'll often see this problem in houses that are located on a hill or very close to one of those massive water towers that help create pressure in a municipal water system.

I can empathize with your low-water-pressure problem. The house I purchased in New Hampshire has minimal water pressure, while the house I moved from had great water pressure - just under 85 pounds per square inch (psi). I'm lucky now to have 45 psi.

My house in New Hampshire is on a well and the pressure gauge clearly shows that my pressure is just above minimum standards. I'm going to install a water pressure booster pump several weeks from now to solve my problem.

There are many possible causes of low pressure. In your case, the main water line feeding your home could have a kink in it that's restricting water flow; the line could be partially clogged with deposits; or you may have an inline water filter that's clogged with debris.

If your home is an older one and has galvanized iron water pipes, the horizontal pipes that run under floor joists could also be clogged. This is very common, though for some reason, the vertical pipes that run between floors don't tend to suffer from this sedimentation issue to the same degree.

Some people suffer from low water pressure in showers and kitchen and bathroom faucets. To comply with federal water-use regulations, shower heads contain flow restrictors. Unfortunately, very tiny pieces of sediment can quickly clog the openings in these restrictors. When enough openings get clogged, water pressure can drop quickly.

Water pressure drops significantly at a kitchen or bathroom vanity faucet for the same reason. But in this case, the pieces of sediment clog holes in the aerator that creates the uniform flow of water.

Shutoff valves within your system could be causing the problem. Perhaps someone turned down the main shutoff valve at your house and didn't open it up fully after a repair was completed.

Your home water pressure might also be suffering because of a faulty water pressure relief valve. You can determine this, with some effort, by installing a water pressure gauge on each side of the pressure relief valve or a pressure-reducing valve.

The gauges tell you the pressure of the water being supplied by the city water main or the well pump. But the secondary pressure gauge, installed downstream of the other valves, will tell you how much the pressure has dropped because of those other devices in your water system.

Tim Carter is a columnist for Tribune Media Services. He can be contacted through his Web site, www.askthebuilder.com.


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