Low Water Pressure at Home: Causes and How to Fix It

What Is Normal Water Pressure?

Normal residential water pressure is between 40 and 80 PSI (pounds per square inch). Below 40 PSI is generally considered low and will cause noticeable performance problems. Above 80 PSI can damage appliances and plumbing fixtures. You can check your water pressure with an inexpensive gauge that attaches to an outdoor hose bib.

Common Causes of Low Water Pressure

Closed or partially closed shutoff valves: The most common (and easiest to fix) cause. Your home has a main shutoff valve where the water line enters the house. If it's not fully open, pressure will be reduced throughout the home. Check both your home's main shutoff and the municipal meter shutoff (on the street side of the meter) — both need to be fully open.

Pressure regulator failure: Most homes have a pressure regulating valve (PRV) that limits incoming municipal pressure to a safe range. When the PRV fails, it can cause either extremely high or extremely low pressure. PRV replacement is a straightforward repair for a licensed plumber.

Galvanized pipe corrosion: Homes with older galvanized steel supply pipes often experience chronically low pressure as the pipes corrode from the inside, reducing the interior diameter over decades. The only real fix is repiping with copper or PEX.

Leaks in the supply line: A significant leak in your main supply line will reduce pressure throughout the house. If your pressure is suddenly lower than normal and you can't find an obvious cause, a supply line leak may be the culprit.

Municipal supply issues: Sometimes low pressure comes from the water utility, not your plumbing. If your neighbors are experiencing the same issue, contact your water company.

Low Pressure in Just One Area

If only one fixture has low pressure, the issue is usually localized — a clogged aerator on the faucet, a partially closed fixture shutoff valve, or a problem with that specific fixture's supply line. Clean the aerator first; it's free and takes two minutes.

For persistent low water pressure throughout your Northern NJ home, call Advantage Plumbing at 973-240-5230 for diagnosis and repair.