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Chronic low water pressure is a condition that just keeps on giving—annoyance. Fixtures like shower heads don’t rinse properly when water pressure drops below their design specs. It can seem like forever for a toilet tank to refill. Waiting for washing machine cycles to finish builds patience and character. Low water pressure may be limited to just one part of the home or only a single fixture. Or, it may be a whole-house phenomenon.

A qualified plumber can attach a meter to check your water pressure. There’s no exact, specific reading officially designated as “Approved.” Household water pressure may range anywhere from about 40 psi (pounds per square inch) up to as high as 80 psi. A lot depends on the pressure of water supplied by your municipal water utility. However, it’s generally accepted that once pressure drops into the 30s, you’ve reached the tipping point where minor inconvenience is soon to be followed by ongoing exasperation.


Here are three probable causes of low water pressure and potential cures:

  • Main shutoff valve not fully open. It happens. Someone turns off the household water supply at the main shutoff valve for some reason, then doesn’t open it all the way afterwards. Those valves can be sticky and stubborn to turn, so it’s not surprising. Check the valve and see if it can be opened any further. But don’t force it. Have a plumber check it out, particularly if you know the valve was closed and opened in the recent past.


  • Pressure regulator maladjusted or defective. The municipal water pressure coming straight off the main line in the street is usually way too high for household plumbing. A regulator valve located in or near your water meter reduces municipal pressure down to safe levels. If someone made a DIY adjustment to the pressure regulator valve in the past—or if the valve is no longer functioning properly—it could be reducing indoor water pressure excessively. A plumber can check the valve for proper function, and adjust or replace as necessary.


  • Mineral deposit accumulation.  Mineral content in municipal water (mostly calcium carbonate) may slowly accumulate inside water supply lines over the years, gradually constricting flow and reducing pressure. Re-piping supply lines is generally the only remedy if the problem extends to the whole house. If the water pressure is limited to just one specific fixture, however, replacing a single supply line may resolve the situation.


Arch Plumbing is located in St.Charles, Missouri and has been in the service business since 2008 providing quality plumbing services.

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