Quick answer
Low water pressure is most often caused by a failing pressure-reducing valve, corroded galvanized pipes, clogged fixture aerators, a partially closed main shutoff, or a hidden leak. Whether it affects one fixture or the whole house tells you a lot about where the problem is.
- One fixture low? Usually a clogged aerator or cartridge — an easy fix.
- Whole house low? Suspect the pressure-reducing valve, main valve, or corroded pipes.
- Sudden whole-house drop can signal a leak — watch for unexplained water use.
- Old galvanized pipe narrows from rust, slowly choking flow over years.
Start by isolating the problem
If only one faucet is weak, the cause is usually local — a clogged aerator, a sediment-filled cartridge, or a partly closed supply valve. If pressure is low everywhere, the cause is upstream: the main valve, the pressure-reducing valve, the pipes, or the water supply itself.
Why it matters
Beyond the daily annoyance, a sudden drop can be the first sign of a hidden leak, and pressure that's too high (a different PRV failure) can damage fixtures and the water heater. Diagnosing the cause protects both comfort and your plumbing.
How it works
The pressure-reducing valve
Many homes have a PRV near where water enters, which lowers high city pressure to a safe 50–70 psi. When it fails, pressure can drop too low (weak flow everywhere) or climb too high (water hammer, dripping relief valves, stressed fixtures). A gauge test confirms it, and the valve can be adjusted or replaced.
Pipes, aerators, and leaks
Corroded galvanized pipe narrows over decades, cutting flow house-wide. Mineral deposits clog aerators and cartridges at individual fixtures. A hidden leak diverts pressure and shows up as unexplained water use or a meter that moves with everything off. Each has a different, targeted fix.
Key terms and context
This guide is written for plumbing decisions in the Tri-State. It uses the same terminology you'll hear from inspectors, technicians, and permit offices.
When to call
If cleaning aerators doesn't help and pressure is low across the home, or if you suspect a leak (damp spots, mildew smell, a spinning meter with fixtures off), have it diagnosed. Guessing at pipe or valve work without measuring pressure usually wastes money.
Why you can trust this
- Reviewed against Comfort Central's licensed-plumbing standards and field service records.
- Pressure measured before any pipe or valve recommendation.
How we build this guidance
- Straight answers first, so you know your options without the fluff.
- Written and reviewed by techs who do this work every day.
- Specific to Tri-State homes, weather, and water.
- Updated 2026-06-01 from real plumbing jobs around the region.
Methodology: Written and reviewed by Comfort Central's licensed plumbing team from real service calls across Hagerstown and the Tri-State. Guidance reflects code requirements and field experience — not a sales pitch.
Last updated: 2026-06-01
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Common questions
Can low pressure mean I have a leak?
It can. A sudden whole-house drop, damp spots, or a water meter that moves with everything turned off all point to a possible hidden leak that should be found quickly to avoid damage.
What's normal household water pressure?
Roughly 50–70 psi is a comfortable, safe range. Below that feels weak; much above 80 psi can damage fixtures and appliances and usually means a pressure-reducing valve needs attention.