High Water Pressure
A gauge reading decides whether pressure is the problem.
By Jonathan West · reviewed 2026-10-28 ·how we research these
Measure first. Screw a hose-thread gauge onto a tap downstream of any pressure-reducing valve (PRV), with every fixture and appliance off, and read the dial. Above 80 pounds per square inch (psi), most plumbing codes require a PRV. Lowering the pressure then means a working PRV, which a licensed plumber adjusts, replaces or installs.
Readings of 60 psi or less meet the target in the Building America Solution Center (BASC), a US Department of Energy (DOE) resource, so no pressure reduction is needed. Banging pipes, a toilet that keeps refilling, dripping faucets and short-lived washing machine hoses are signs of excess pressure.
Two faults look similar but follow different paths. A water heater relief valve that drips most often has a thermal expansion cause, which the thermal expansion section covers. Low pressure is the opposite fault, covered on the low water pressure in house page.
Measure Before You Change Anything
Static pressure is the reading taken with no water flowing. Turn off every fixture and appliance, screw the hose-thread gauge onto a tap, and read the dial. Pick a tap downstream of any PRV, such as the washing machine supply.
Do not use an outdoor spigot unless you know it sits past the PRV. Many homes plumb outdoor hose bibs (spigots) ahead of the PRV, so a gauge there can read unregulated main pressure rather than the pressure the house receives.
Pressure can vary through the day on a municipal supply, so take readings at more than one time. At DIY Repair Guide, we compiled the table below from the thresholds BASC gives, with the middle row added as our own grouping of the range between them. Local plumbing code adoption and amendment vary, so the threshold your jurisdiction applies may differ.
| Reading | Meaning | Next step |
|---|---|---|
| 60 psi or less | Meets the BASC target of 60 psi for service water entering a home | No regulator is needed at this reading. Go to the symptom table for other causes. |
| 61 to 80 psi | Above the 60 psi target and below the 80 psi level where most plumbing codes require a PRV | Local plumbing code decides whether a PRV is required, so check your local code. |
| Above 80 psi | Most plumbing codes require a PRV where supplied pressure exceeds 80 psi | A licensed plumber adjusts or replaces an existing PRV, or installs one if none exists. |
Signs of Excess Pressure
The risks BASC lists are ruptured supply lines and washing machine hoses, leaking water heaters, dripping faucets, damaged fixtures, and louder dishwashers and clothes washers. BASC says regulating pressure to the 60 psi target lowers water use and extends fixture life.
A dripping relief valve is also a sign, but the same drip can come from thermal expansion in a closed system instead of supply pressure.
Excess pressure shows up as:
- Banging or hammering pipes
- A toilet that keeps refilling
- Dripping faucets
- A water heater relief valve that drips
- Short-lived washing machine hoses
The Pressure-Reducing Valve
On a municipal supply, the PRV is typically a bell-shaped brass valve next to the main shutoff on the incoming service line. It reduces the pressure the house receives from the utility to a lower level.
Private wells regulate pressure with a pump, pressure switch and bladder tank instead of a PRV. Ask a licensed plumber about high readings on a well.
If a PRV is installed and the reading is high, the PRV may have failed or be set too high. Adjusting, repairing or replacing a PRV on the main supply is plumber work.
No Regulator Installed
If no PRV exists and the reading is above 80 psi, a licensed plumber installs one. Installing a PRV is plumber work.
The cost to install a PRV varies by region, so get written quotes from licensed plumbers. The plumber cost page has typical figures.
Thermal Expansion and the Relief Valve
A temperature and pressure (T&P) relief valve sits near the top of a storage water heater, with a discharge pipe running down toward the floor. It is a safety device that opens if the water exceeds roughly 210 degrees Fahrenheit or 150 psi.
A discharging T&P valve is generally doing its job. The most common cause is thermal expansion in a closed plumbing system, meaning one with a check valve, a PRV or a backflow preventer on the incoming main. Heated water expands, has nowhere to go, and pressure climbs until the valve lifts.
The repair in that case is a thermal expansion tank on the cold supply. A new relief valve does not address that cause. High static pressure may also need a PRV, so the readings from the first section still apply.
Replacing a T&P valve typically costs $150 to $350, a typical US figure for orientation only. Replacing the valve does not stop the drip if the valve is venting excess pressure.
See the water heater leaking page, and the water heater relief valve leaking page covers a dripping valve. Repairs that involve gas, venting, the burner or live wiring belong to a licensed plumber, heating, ventilation and air conditioning (HVAC) technician or electrician.
Why Not to Throttle the Main Valve
Shutting the main valve part-way is not a fix. It throttles flow, and it can damage the valve.
The control that reduces pressure is the PRV, and a licensed plumber sets it.
If you need to know which valve type your main shutoff is, see the ball valve vs gate valve comparison.
Symptom-to-Cause Table
We compiled the table below from the signs and thermal expansion cases above. It maps each symptom to its likely cause, the first check, and who does the work.
| Symptom | Likely cause | First check | DIY or plumber |
|---|---|---|---|
| Banging or hammering pipes | Excess pressure | Static pressure reading at a tap downstream of the PRV | Measuring: DIY. Regulating: plumber |
| Toilet that keeps refilling | Excess pressure | Static pressure reading | Measuring: DIY. Regulating: plumber |
| Dripping faucets | Excess pressure | Static pressure reading | Measuring: DIY. Regulating: plumber |
| Short-lived washing machine hoses | Excess pressure | Static pressure reading | Measuring: DIY. Regulating: plumber |
| Water heater relief valve drips | Most often thermal expansion in a closed system | Whether a check valve, PRV or backflow preventer sits on the incoming main | Plumber. A thermal expansion tank is the usual repair |
| Reading above 80 psi | Failed or misset PRV, or no PRV installed | Location of the PRV next to the main shutoff | Plumber adjusts, replaces or installs |
| Reading of 60 psi or less with pipes still banging | No cause is named for this reading | Repeat readings at more than one time of day | Plumber, if the sound continues |
| Water heater leaking | Not covered by the pressure reading | Symptoms on the water heater leaking page | Plumber, HVAC technician or electrician for gas, venting, burner or wiring work |
When to Call a Plumber
Cost figures here are typical US figures for orientation only. The cost to install a PRV varies by region. T&P valve replacement costs $150 to $350 (typical US figures), covered in the thermal expansion section.
What would change this answer: if the gauge reads 60 psi or less and pipes still bang, pressure is not the likely cause of the banging. BASC names no other cause for banging pipes, so a licensed plumber is the next step.
Take readings at more than one time of day. If any reading is above 80 psi, get a written quote from a licensed plumber to address high water pressure.
Call a licensed plumber in any of these cases:
- A reading above 80 psi
- A PRV that has failed or appears to be set too high
- No PRV on a high reading
- A T&P valve that still discharges after you measure the pressure
Do not shut the main valve part-way to lower pressure. It throttles flow and can damage the valve. Adjusting, repairing or replacing a PRV is plumber work.
Common questions
Is 90 PSI too high for residential water pressure?
Yes. A reading of 90 psi is above the 80 psi level where most plumbing codes require a pressure-reducing valve (PRV), and above the 60 psi target from the Building America Solution Center (BASC). Local code adoption and amendment vary, so the threshold your jurisdiction applies may differ.
How do I lower water pressure in my house?
Install or adjust a working pressure-reducing valve (PRV), which a licensed plumber does. Measure first, because readings of 60 psi or less meet the BASC target and need no regulator. Shutting the main valve part-way is not a fix, because it throttles flow and can damage the valve.
What is normal water pressure for a house?
The BASC source sets 60 psi as the maximum target for service water entering a home. Readings above 80 psi call for a PRV under most plumbing codes. No separate normal range is given here.
How do I check water pressure at home?
Screw a hose-thread pressure gauge onto a tap downstream of any PRV, such as the washing machine supply or the water heater drain. Turn off all fixtures and appliances, then read the static pressure. Take readings at more than one time, because municipal pressure can vary through the day.
Can high water pressure damage appliances?
Yes, according to BASC. It lists ruptured supply lines and washing machine hoses, leaking water heaters, damaged fixtures, and louder dishwashers and clothes washers as risks of excess pressure.