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How to fix low water pressure

We'll find and fix the cause of low water pressure—aerator, valves, or PRV.

How-to · Home plumbing
30–60 min
What you'll need
  • Pressure gauge (to measure at outdoor faucet)
  • Vinegar (for cleaning aerators)
  • Adjustable wrench

At a glance

  • Clean or replace faucet aerators—mineral buildup is a common cause of low flow at a single fixture.
  • Check that shutoff valves under sinks and behind toilets are fully open.
  • Inspect the pressure-reducing valve (PRV) near the main—adjust or replace if it is set too low or faulty.
  • For whole-house low pressure: check the main shutoff, PRV, and consider pipe corrosion or municipal supply issues.
  • Call a plumber if the main line is corroded, the PRV will not adjust, or you have galvanized pipes.
Quick triage — pick your path

Get started

Choose the option that matches what you see. You can jump straight to that section.

Steps

Goal: Identify and fix the cause of low water pressure.

  • Run water at several fixtures. Determine if it is one fixture or whole house.
  • Good: You know the scope. Proceed to Single fixture or Whole house.
  • Bad: Unclear—check aerators first, then valves.

Single fixture

Goal: Fix low pressure at one faucet.

  • Clean the aerator. Check the shutoff valve under the sink.
  • Good: Flow improves. Proceed to Verification.
  • Bad: No change—check the supply line or call a plumber.

Whole house

Goal: Fix system-wide low pressure.

  • Check the main shutoff and PRV. Inspect for corrosion or leaks.
  • Good: Pressure improves. Proceed to Verification.
  • Bad: PRV will not adjust or pipes are corroded—call a plumber.

When to get help

Call a plumber if:

  • The main shutoff or PRV is stuck or will not adjust.
  • You have galvanized pipes and pressure has gradually dropped.
  • The municipal supply pressure is low (neighbors may have the same issue).

Verification

  • Water flows at normal pressure at all fixtures.
  • Pressure gauge reads 40–80 psi at an outdoor faucet (if you have a PRV).
  • Aerators are clean and valves are fully open.

Reviewed by Blackbox Atlas

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