Low Water Pressure Throughout the House
Low pressure throughout the whole house is different from low pressure at one faucet. Whole-house low pressure typically points to the pressure reducing valve (PRV), the main shutoff, or the water supplier. Single-fixture low pressure is usually a clogged aerator or faucet cartridge.
Step-by-Step Fix
- 1
Test if it's whole-house or one fixture
Check multiple faucets on different floors. If only one faucet has low pressure, clean its aerator (the screen at the tip) — unscrew it and soak it in vinegar for 30 minutes. If multiple fixtures are low, continue below.
- 2
Check the main shutoff valve
Find the main water shutoff valve (usually near the water meter, at the front of the house). Make sure it's fully open — a gate valve should be turned fully counterclockwise, a ball valve should be parallel to the pipe.
- 3
Check the pressure reducing valve (PRV)
Most homes have a PRV — a bell-shaped device on the main supply pipe. Normal home pressure is 45–80 PSI. Attach a pressure gauge to an outdoor hose bib to test. If pressure is under 45 PSI, try turning the PRV adjustment screw clockwise a quarter turn and retesting.
- 4
Look for a shutoff that's partially closed
If you recently had any work done, check that all service valves under sinks and behind toilets are fully open.
- 5
Check with a neighbor
If your neighbor also has low pressure, contact your water utility — it may be a supply issue on the main line, not something you can fix.
⚠️ Safety Notes
- Don't raise PRV pressure above 80 PSI — this stresses pipes and can cause leaks and damage to appliances.
- A PRV that's completely failed needs to be replaced — this requires shutting off water at the street and is best done by a plumber.
When to Call a Pro
If adjusting the PRV doesn't restore pressure, or if the PRV is leaking, have a plumber replace it. Also call if you have galvanized pipes (common in homes built before 1970) — they corrode internally and may need replacement.
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