Why Is My Water Pressure Low? Common Causes and Fixes

You turn on the shower and get a weak trickle. Low water pressure is one of the most common plumbing complaints in American homes, and the cause is often simple. The trick is to test one thing at a time instead of guessing.

This guide walks through the usual culprits, from a dirty faucet screen to a worn pressure regulator, and shows what you can fix yourself before paying for a service call. A little routine care, covered in our plumbing maintenance tips, prevents many of these problems.

For the complete overview, read Plumbing Maintenance 101: Preventive Care, Winterization, and Long-Term System Health.

Is the problem one fixture or the whole house?

If only one faucet is weak, the problem is at that fixture; if every tap is slow, the cause is in the main line, valve, or regulator.

Start by testing pressure at several points. Run the kitchen cold tap, then a bathroom tap, then an outdoor spigot. If the outdoor spigot is strong and the kitchen tap is weak, the issue sits between them, not in the city supply.

This one test saves time. It tells you whether to open a faucet or head for the basement. For a deeper walkthrough of the whole system, see what causes low water pressure in a house and how to fix it.

Clogged aerator or cartridge

Mineral scale and debris block the small screen on the faucet tip or the cartridge inside, cutting flow at that fixture only.

Unscrew the aerator from the faucet tip by hand or with pliers wrapped in tape. Look for white crust, grit, or black specks. Soak the parts in white vinegar for a few hours, scrub with a soft brush, and rinse before reassembling.

If the aerator is clean but flow is still weak, the cartridge or mixing valve is likely scaled. Shut off the supply stops under the sink, remove the handle, and pull the cartridge. Replace it with the same model rather than trying to clean it.

• Soak aerator parts in vinegar, then scrub and rinse
• Check the supply stop under the sink is fully open
• Replace a scaled cartridge instead of cleaning it
• Test flow before and after to confirm the fix

Valves, regulators, and the main shutoff

A partly closed shutoff valve or a worn pressure regulator reduces flow to the entire home.

Find the main shutoff where the supply enters the house, often near the water meter or in a basement crawl space. Turn it fully counterclockwise to confirm it is open. Gate valves fail in a half-open position and can look open when they are not.

The pressure regulator, a bell-shaped valve on the main line, holds household pressure steady. When it fails, pressure can drop or spike. A plumber can test it with a gauge and rebuild or replace it. This job is not a DIY task because it involves the main supply.

Pipes, leaks, and municipal supply

Corroded galvanized pipes, hidden leaks, or a problem on the city main can lower pressure throughout the home.

Older galvanized steel pipes rust from the inside, narrowing the bore over decades. If your home still has them and pressure has fallen slowly over years, that is the likely cause. Repiping is the long-term fix.

A hidden leak under a slab or in a wall also drops pressure. Check for a spinning water meter with all fixtures off. If neighbors report the same issue, the problem is on the municipal side and worth a call to the water department.

Prevention and when to call a plumber

Regular flushing, soft water where hardness is high, and prompt leak repair keep pressure steady and prevent scale buildup.

Flush the water heater yearly to remove sediment that can restrict hot-water flow, following the steps in water heater maintenance. Clean faucet aerators twice a year, and learn how to prevent clogged drains so slow buildup does not become a blockage.

Call a licensed plumber when pressure drops at every fixture, when you hear water running with nothing on, or when the regulator needs service. These point to main-line work that requires a gauge, permits, and experience.