Why Is My Water Pressure Low and How Do I Fix It?

The first diagnostic question splits every low pressure problem in half: is it one fixture or the whole house? If only the kitchen sink dribbles while the bathroom shower runs strong, the problem lives in that fixture or its supply line, usually a clogged aerator, a partially closed shutoff valve, or a worn fixture. If every tap in the house slows at the same time, the problem lives in the shared supply: the pressure regulator, the main line, or a leak somewhere in the system.

Start by being honest about what changed. A house that has always had modest pressure is a different story from one where pressure suddenly dropped, and different again from one where it has been falling over years. Sudden drops point to a single event: a burst or leaking line, a stuck valve, or in the winter, a partially frozen supply pipe. Slow declines often point to buildup, a failing regulator, or municipal supply issues in your area.

Clean the aerators and showerheads before calling anyone. The aerator, the little mesh screen inside the spout tip, traps mineral scale, and in hard-water areas it is the single most common cause of a weak kitchen or bath faucet. Unscrew it, soak the screen in vinegar for an hour, scrub the scale off with an old toothbrush, and reinstall. Showerheads collect the same scale in the nozzles, and the same soak revives them. This takes fifteen minutes, costs nothing, and fixes a surprising share of one-fixture problems.

While you are in the bathroom, check the shutoff valves under the sink and behind the toilet: a valve that was closed partway during a repair years ago, then forgotten, will starve exactly that fixture forever. Open them fully. Also check the water heater's main valve fully open, and if you have a whole-house filter or water softener, its bypass and service valve positions, because a filter past its life or a softener in bypass starves the whole house of pressure.

When every tap is weak, move past the fixtures. First is the pressure regulator, the bell-shaped device on the main line where water enters, commonly found in homes with city supply. Regulators wear out and let pressure sag over time; a plumber can adjust or replace one in a visit, and it is the most common whole-house cause after fixture issues. Second is a leak: a hidden leak wastes pressure in addition to water, and the meter test from our leak guide will tell you if water is flowing when it should not be. Third, in winter, a supply line that runs through an unheated crawl space or garage can freeze partially and choke the flow until it thaws; that is a seasonal pattern that usually resolves itself but warns you to insulate the line before next winter.

If nothing else explains it, talk to neighbors and the water authority about area-wide pressure; municipal pressure changes with infrastructure work, firefighting demand, and seasonal usage, and a temporary system-wide dip is not your plumbing's fault. A gauge on an outside spigot or laundry valve can measure your actual pressure, and a plumber can confirm whether you are below the typical household range.

Most homes run comfortably with city pressure in the typical household range, and if your house is far off it, a plumber can adjust the regulator so showers and sprinklers both work as intended. Too high is a problem too, hammering pipes, straining hoses and fixtures, and wearing out the water heater, so finding the middle matters more than chasing maximum. If your aerators are clean, the valves are open, the regulator has been checked, and the pressure is still weak in one stubborn fixture, the block may be deeper in that supply line, scale in a galvanized pipe, a problem that is plumber territory.

If you are buying an older home, low pressure is worth asking about before closing, because in an old house it can mean 60 or 70 years of scale inside the pipes, and repiping a home is a significant line item. Sellers should fix obvious pressure complaints before showings; buyers who cannot shower at the walkthrough are buyers who discount the whole house.