Plumbing·Water pressure

How to reduce water pressure in a house (2026)

Partially verified

Quick Answer

To reduce water pressure in a house, first confirm that the pressure is actually too high, then adjust the home's pressure reducing valve if one is fitted. If there is no valve, or the pressure stays high or fluctuates badly, the fix is usually to have a suitable pressure reducing valve installed or replaced by a plumber. Avoid over-tightening fittings or guessing settings, because reducing pressure too far can leave poor flow at taps and appliances.

Overview

High water pressure can make showers feel forceful, but it also puts extra strain on taps, hoses, valves, toilet fill mechanisms and appliance inlet parts. In many homes, the simplest way to reduce it is by adjusting the pressure reducing valve, often found near the main internal stop valve or where the water service enters the property. The sensible approach is to check whether high pressure is really the problem, identify the valve correctly, make small adjustments, and test the result at a few fixtures. This matters because pressure problems are sometimes confused with other issues. A noisy pipe, hammering after taps shut, or uneven flow can also be caused by failed valves, blocked strainers, faulty expansion control, or a problem on the incoming supply. If your home has a combi boiler, unvented cylinder, water softener or other treatment equipment, changing pressure carelessly can affect how these systems perform. If you cannot find a pressure reducing valve, if the adjusting screw is seized, if the pressure changes wildly, or if you have any doubt about the incoming main or your plumbing layout, it is usually best to use a qualified plumber. The job itself is often straightforward, but identifying the right component and adjusting it safely is the important part.

Who this is for

Homeowners or tenants who have access to the main water entry point and want to reduce excessively high household water pressure without altering the plumbing system unnecessarily.

What you’ll need

Water pressure gauge suitable for domestic plumbing, ideally one that can attach to a hose tap or similar outlet
Screwdriver, spanner or Allen key if required by the pressure reducing valve adjustment mechanism
Torch
Cloth or small towel for drips
Manufacturer instructions for the installed pressure reducing valve, if available
Access to the main stop valve and incoming water pipework

Before you start

Check whether the problem is truly high pressure rather than poor flow control, water hammer, or a faulty tap or appliance valve. Locate the main stop valve and see whether a pressure reducing valve is already installed on the incoming supply. If you live in a flat, rented property, or building with shared water services, confirm who is responsible before making adjustments. If you have an unvented hot water system, expansion vessel, booster pump or other specialist equipment, review the equipment manual first.

Step-by-step

1
Confirm the symptoms point to high pressure
Look for common signs such as taps that blast water out, frequent dripping from taps or appliance connections, banging when valves close, toilets that fill aggressively, or repeated failures of flexible hoses and inlet valves. Test more than one tap so you know whether the issue affects the whole house rather than a single fitting.
Why: This helps you avoid adjusting the whole house pressure when the real fault is a local valve, a blocked aerator, or a defective appliance connection.
2
Measure the incoming pressure
Attach a suitable pressure gauge to a convenient outlet connected to the mains supply, such as an outside tap if one is available, and take a reading when water use in the house is low. Compare the reading with the guidance for your plumbing fixtures or the setting range stated on the installed pressure reducing valve or appliance manuals.
Why: You need an actual measurement before changing anything. Pressure that only feels strong may still be within a normal range, while genuinely excessive pressure can shorten the life of plumbing components.
3
Find the pressure reducing valve
Trace the incoming cold water pipe from where it enters the property and look for a valve body with an adjustment point on top or at the end, often close to the stop valve or meter. Check the valve body for a make or model marking and look up the manufacturer's instructions if they are not already available.
Why: Adjusting the wrong component can shut off water, damage a fitting, or do nothing at all. Identifying the correct valve also tells you how its adjustment mechanism works.
4
Make a small adjustment
Using the tool required for your valve, make a small adjustment in the direction indicated by the manufacturer to reduce outlet pressure. If there are no markings and you do not have instructions, stop rather than guessing aggressively. After each small change, pause and let the system settle.
Why: Pressure reducing valves respond best to gradual changes. Large adjustments make it easy to overshoot and leave the house with poor water performance.
5
Re-test pressure and check fixture performance
Take another gauge reading and then test a kitchen tap, a bathroom tap, a shower and any sensitive appliances if practical. Check that flow is still usable, toilets refill properly, and there are no new noises or leaks around the valve and nearby joints.
Why: A gauge confirms the pressure change, but fixture testing shows whether the new setting works in real use across the house.
6
Fine-tune only if needed
Repeat the adjust-and-test process in small increments until the pressure is reduced to a sensible level for the property and its appliances. If the pressure creeps back up, fluctuates a lot, or cannot be reduced, stop adjusting and arrange inspection or replacement of the valve.
Why: Persistent instability usually points to a failing pressure reducing valve, debris in the valve, thermal expansion issues, or a supply-side problem that adjustment alone will not cure.
7
Record the final setting and monitor the system
Make a note of the gauge reading, valve make and any visible setting reference. Over the next few days, watch for dripping taps, unusual noise, or weak flow at peak use times.
Why: A simple record makes future fault-finding easier and helps a plumber if the problem returns.

Why this works

A pressure reducing valve lowers the pressure from the incoming mains supply to a controlled downstream level for the house. Reducing excessive pressure cuts mechanical stress on seals, hoses, taps and appliance valves, which can reduce leaks, noise and premature wear.

Common mistakes to avoid

Adjusting a valve without first measuring pressure
Confusing pressure with flow rate and trying to fix a blockage or poor pipe sizing by altering pressure
Making large adjustment turns instead of small changes followed by testing
Adjusting the main stop valve instead of the pressure reducing valve
Ignoring leaks, drips or noise after adjustment
Trying to force a seized or corroded adjustment mechanism

Troubleshooting

Water pressure still feels too high after adjustment

Re-check with a gauge, confirm you adjusted the correct valve, and look for a failed or bypassing pressure reducing valve. If pressure remains high, the valve may need servicing or replacement.

Pressure becomes too low throughout the house

Return the valve slightly towards its previous setting and re-test. Also check whether strainers, stop valves or filters are partially blocked, as these can reduce flow and be mistaken for low pressure.

Pressure changes during the day

Some variation can come from supply conditions, but large swings may indicate a faulty pressure reducing valve, debris in the valve, or another plumbing control issue that needs professional diagnosis.

Banging pipes continue even after reducing pressure

The issue may be water hammer caused by fast-closing valves, loose pipework or failed arrestors rather than pressure alone. Secure pipework and have the system checked if the noise persists.

The valve leaks after adjustment

Do not keep adjusting it. Shut off water if the leak is significant and arrange repair or replacement, because disturbed old seals or a failing valve can worsen quickly.

Compare your options

Adjust existing pressure reducing valve

Best for: Homes that already have a working valve and only need a modest correction

Pros: Usually quick, low disruption, no major plumbing changes

Cons: Only works if the valve is fitted and functioning correctly

Replace or install a pressure reducing valve

Best for: Homes with no existing valve, a failed valve, or incoming pressure that is consistently too high

Pros: Provides proper whole-house control and better long-term protection for plumbing and appliances

Cons: Usually needs a plumber and may require pipework changes

Use local flow restrictors or appliance-specific regulators

Best for: Single fixtures that feel too forceful when whole-house pressure is otherwise acceptable

Pros: Targeted solution, can reduce water use at specific outlets

Cons: Does not solve excessive pressure across the whole house

Option	Best for	Pros	Cons
Adjust existing pressure reducing valve	Homes that already have a working valve and only need a modest correction	Usually quick, low disruption, no major plumbing changes	Only works if the valve is fitted and functioning correctly
Replace or install a pressure reducing valve	Homes with no existing valve, a failed valve, or incoming pressure that is consistently too high	Provides proper whole-house control and better long-term protection for plumbing and appliances	Usually needs a plumber and may require pipework changes
Use local flow restrictors or appliance-specific regulators	Single fixtures that feel too forceful when whole-house pressure is otherwise acceptable	Targeted solution, can reduce water use at specific outlets	Does not solve excessive pressure across the whole house

Alternatives

Install or replace a whole-house pressure reducing valve
Fit flow restrictors or regulated shower valves at specific fixtures
Ask the water supplier whether there is a supply-side issue if pressure has changed suddenly

Pro tips

Take a photo of the valve before adjusting it so you can return to the starting position if needed
Test pressure when other taps and appliances are not running for a clearer baseline reading
If the valve body has a directional arrow, make sure you have identified the inlet and outlet correctly before troubleshooting
Check flexible appliance hoses and tap connectors after reducing pressure, as old seals sometimes start leaking when disturbed by testing

Safety notes

Do not dismantle a pressure reducing valve while the water supply is on
Use the correct tool to avoid rounding off the adjustment point
Be careful around electrical appliances or sockets if testing near a utility area
If you are unsure whether a component belongs to a sealed hot water system or specialist installation, stop and get qualified help

Legal & regulatory notes

Requirements for water fittings and plumbing work vary by country and sometimes by region. In some places, certain plumbing work must comply with water supply regulations or be carried out by an approved or licensed professional, especially where it affects potable water systems or unvented hot water equipment. Check local rules and the manufacturer's instructions for any installed valve or system.

What this guide does not cover: This guide covers reducing whole-house mains water pressure by checking and adjusting an existing pressure reducing valve. It does not cover installing new pipework, servicing a specific valve model, diagnosing all causes of water hammer, or work on unvented hot water systems and other specialist installations.

Cost considerations

Adjusting an existing working valve is usually inexpensive if you already have access and a gauge. Costs rise if a valve needs replacing, if access is poor, or if other faults such as water hammer, failed hoses or appliance damage have already developed from high pressure.

Prefer to hire a professional?

If this job is beyond a confident DIY — or the work needs to be done by a licensed professional — you can find a verified plumber through Trade Directory (tradedirectory.co.nz), New Zealand's directory of real, verified trade businesses. Compare local tradespeople, read their details and request quotes before you commit.

Find a plumber on Trade Directory

Frequently asked questions

How do I know if my house even has a pressure reducing valve?+

Look on the incoming mains pipe after it enters the property, often near the main stop valve or meter. It is usually a larger inline fitting with an adjustment mechanism and sometimes a strainer cap or pressure gauge port.

Can I just partly close the main stop valve to reduce pressure?+

That is generally not the right fix. Part-closing the stop valve mainly restricts flow and can create poor performance or valve wear without properly controlling downstream pressure.

Will reducing water pressure also reduce water use?+

It can help in some situations, especially at fixtures that currently discharge very forcefully, but the main benefit is protecting plumbing and improving control. Actual water use also depends on fixture type and how long water is run.

Why does the pressure seem high only at certain times?+

Supply conditions can vary, but noticeable swings can also point to a faulty pressure reducing valve or another plumbing control issue. Measuring with a gauge at different times helps confirm what is happening.

Should I call a plumber instead of adjusting it myself?+

Yes if you cannot identify the valve confidently, the valve leaks or is seized, the pressure remains unstable, or your system includes specialist equipment such as an unvented cylinder or booster arrangement.

Sources & references

Guidance on this page is traced to documented sources. Last checked 24 September 2026.

U.S. Environmental Protection Agency WaterSense · government
Supports the general importance of fixing household leaks and the practical link between leaking plumbing fixtures and water waste; relevant when high pressure contributes to drips and fixture wear.

The basic method of identifying, measuring and adjusting domestic water pressure changes little, though specific valve designs and local plumbing rules vary.