Low Water Pressure
Weak water flow from faucets, showers, or throughout the entire house.
Low Water Pressure: Low water pressure is caused by corroded pipes, a failing pressure regulator, a partially closed valve, or municipal supply issues. If pressure is low at one fixture, the aerator or cartridge is likely clogged. If it's house-wide, check the main shutoff valve (make sure it's fully open) and the pressure regulator. Diagnosis costs $100–$200.
What Causes This?
Corroded or Clogged Pipes
Galvanized steel pipes (common in pre-1970s homes) corrode internally, reducing flow. Mineral deposits also accumulate in pipes over decades.
Failing Pressure Regulator
The pressure regulator (PRV) controls incoming water pressure. When it fails, pressure can drop significantly. Typical lifespan is 10–15 years.
Partially Closed Valve
The main shutoff valve or meter valve may not be fully open, especially after a recent repair. Even a quarter-turn can reduce pressure throughout the home.
Clogged Aerator or Fixture
If only one faucet has low pressure, the aerator screen or cartridge is likely clogged with mineral deposits. Easy DIY fix.
Water Leak
A hidden leak (slab leak, pipe leak) diverts water away from fixtures, reducing pressure. Check your meter with all fixtures off — if it's still moving, you have a leak.
Municipal Supply Issue
City water main breaks, maintenance, or high neighborhood demand (summer watering) can temporarily reduce pressure.
Can It Wait?
Low water pressure is inconvenient but not dangerous. However, if it developed suddenly, it could indicate a burst pipe or major leak that needs prompt attention.
What Does It Cost?
| Item | Cost Range |
|---|---|
| Aerator Cleaning/Replacement | $5–$20 |
| Pressure Regulator Replacement | $250–$500 |
| Leak Detection | $200–$600 |
| Pipe Section Replacement | $500–$2,000 |
| Whole-House Repipe | $4,000–$15,000 |
Repair vs. Replace
Repair
Repair if: the issue is a single fixture (aerator), a pressure regulator, or an isolated pipe section.
Replace
Repipe if: you have galvanized pipes with widespread corrosion. PEX repiping ($4,000–$15,000) restores full pressure and eliminates future corrosion problems.
Rule of thumb: If your home has galvanized pipes and low pressure is affecting multiple fixtures, repiping is a permanent solution. Patching individual sections is a temporary fix on a deteriorating system.
When to Call a Contractor
- ✓Pressure dropped suddenly throughout the home
- ✓Multiple fixtures have low pressure (not just one faucet)
- ✓You've checked the main valve and it's fully open
- ✓Your water bill increased without increased usage (possible hidden leak)
- ✓You have galvanized pipes and pressure has gradually worsened
Related Problems
Low Water Pressure — FAQ
Why is my water pressure so low?
If it's one fixture, clean the aerator. If it's the whole house, check that the main valve is fully open, and check with your water utility for area issues. For persistent house-wide low pressure, the cause is usually corroded pipes, a failing pressure regulator, or a hidden leak.
How do I check my water pressure?
Attach a pressure gauge ($10 from any hardware store) to an outdoor hose bib. Normal residential pressure is 40–60 PSI. Below 40 PSI indicates a problem. Above 80 PSI is too high and requires a pressure regulator to prevent pipe damage.
What causes sudden loss of water pressure?
Sudden pressure loss usually indicates a water main break (check with neighbors), a burst pipe on your property, a partially closed valve (after recent plumbing work), or a municipal supply disruption. Check your water meter — if it's spinning with all fixtures off, you have a leak.