What this service solves
- Weak flow at one or all fixtures
- Pressure that drops when two fixtures run
- Banging pipes and running toilets caused by high pressure
- Failed pressure-reducing valves
Common symptoms
- Weak showers
- Slow-filling toilets
- Pressure that fluctuates
- Water hammer
- Dripping relief valve on the water heater
- Frequent supply hose or toilet fill valve failure
Most likely causes
Clogged aerators or showerheads
Mineral scale and debris restrict flow at one fixture.
Partly closed valves
A main shutoff or fixture valve not fully open after work is a common, easy fix.
Failed pressure-reducing valve (PRV)
A PRV can fail low (weak flow) or fail high (excess pressure).
Corroded pipe
Galvanized pipe narrows inside over decades.
Leaks
A large leak reduces pressure throughout the house.
Municipal supply
Some neighborhoods simply have lower or higher street pressure.
How the problem is diagnosed
- Measure static pressure at a hose bib with a gauge.
- Compare hot and cold, and different fixtures, to find the pattern.
- Check aerators, valves and the PRV.
- Test for leaks with the meter.
Repair and replacement options
| Option | Best for | What to know |
|---|---|---|
| Clean or replace aerators | One weak fixture | Often a minutes-long fix. |
| PRV adjustment or replacement | Whole-house high or low pressure | Most residential PRVs are adjustable within a range. |
| Expansion tank | Closed systems with thermal expansion | Absorbs pressure spikes from water heating. |
| Repiping | Corroded galvanized lines | Restores full pipe diameter. |
What a plumber normally does
- Measure
- Isolate the cause
- Repair or adjust
- Re-measure
Emergency warning signs
- Pressure suddenly drops to near zero (possible main break)
- Relief valve discharging continuously
If you see any of these, shut off water first. See emergency plumbing steps.
What affects the cost
We don’t publish national price figures because real quotes vary too much by region, access and the condition of your system. These are the factors that move the price:
- Cause
- PRV location and access
- Need for an expansion tank
- Pipe replacement
Ask for a written quote that names the method, materials and any permit or restoration work before work begins.
DIY vs. calling a professional
Reasonable for homeowners
- Testing pressure with a hose-bib gauge
- Cleaning aerators and showerheads
- Confirming valves are fully open
Call a professional for
- PRV replacement
- Expansion tank installation
- Repiping
Prevention and maintenance
- Check pressure yearly
- Keep pressure in the commonly recommended 40–80 psi range
- Descale fixtures in hard-water areas
Specific water pressure problems services
Water Pressure Problems: common questions
Can a plumber fix low water pressure?
Yes, once the cause is known. Low pressure at one fixture is usually a clogged aerator or cartridge. Whole-house low pressure can come from a failed regulator, a partly closed valve, corroded pipe, a leak or low municipal pressure.
What is normal household water pressure?
Many plumbing codes and manufacturers use 80 psi as a maximum, and most homes are comfortable in the 40–80 psi range.
Why is my water pressure low only in the shower?
A clogged showerhead or a worn mixing valve cartridge is the usual cause. If both hot and cold are weak only at that shower, the valve is likely the issue.
Is high water pressure bad?
Yes. Sustained high pressure shortens the life of supply hoses, toilet fill valves, faucets, water heaters and appliances, and it increases leak risk.
Why does my pressure drop when someone flushes?
Some drop is normal. A large drop can mean undersized or corroded pipe or a failing regulator.
