A powerful shower can feel convenient, but excessive water pressure can place unnecessary stress on pipes, taps, flexible hoses and appliances. It can also make water hammer worse and contribute to leaks.
If you suspect high water pressure in house plumbing, a pressure-limiting valve (PLV) may need to be checked. However, strong water flow does not necessarily mean pressure is too high. A pressure reading should be taken before assuming the valve has failed.
What Is Considered High Water Pressure?
Water pressure is measured in kilopascals (kPa). Under Australian plumbing requirements, static pressure at building outlets is generally limited to 500 kPa, excluding fire service outlets.
Static pressure is measured when no water is flowing.
A home does not necessarily need to operate at exactly 500 kPa. The appropriate pressure depends on the property’s plumbing design, elevation, appliances and incoming supply.
A licensed plumber can measure the pressure and determine whether it is appropriate for the home’s plumbing system.
What Does a Pressure-Limiting Valve Do?
A pressure-limiting valve, or PLV, controls the water pressure supplied to downstream plumbing.
Depending on the system, a valve may protect:
- The entire house
- A hot water system
- A particular section of pipework
Some installations use fixed-pressure PLVs, while others use adjustable pressure-reducing valves.
If a valve becomes worn, blocked, damaged or unsuitable for the installation, it may no longer regulate downstream pressure correctly.
7 Signs of High Water Pressure in a House
1. Water Suddenly Feels Too Forceful
Water may splash from basins, feel unusually harsh in the shower or come out of an outdoor tap with excessive force.
A sudden change across multiple hot and cold outlets is worth investigating.
However, flow and pressure are not the same thing. A blocked aerator can affect flow, while a larger outlet can produce strong flow even when pressure is normal.
A pressure gauge provides a more reliable indication than how the water feels.
2. Pipes Bang When Water Stops
A loud bang when a tap or appliance valve closes can be a sign of water hammer.
Moving water has momentum. When it stops suddenly, the resulting pressure surge can cause pipes to vibrate or knock.
High pressure can make water hammer more noticeable, but it is not always the cause. Loose pipework, high water velocity and fast-closing valves can also contribute.
If banging occurs regularly, a plumber should identify the cause rather than assuming the PLV is faulty.
3. Taps, Toilets or Valves Keep Leaking
Repeated leaks from taps, toilet cisterns and valves may indicate excessive pressure placing additional stress on seals and components.
However, leaks can also result from:
- Age
- Corrosion
- Worn seals
- Poor installation
- Damaged components
A pattern of several fixtures developing problems around the same time is a good reason to include a pressure check as part of the investigation.
4. Flexible Hoses or Appliance Connections Look Stressed
Flexible hoses are used beneath sinks, toilets and many appliances. Excessive pressure can add stress to hoses, fittings and connections.
Look for:
- Bulging
- Rust or corrosion
- Fraying
- Dampness
- Damaged connections
If a flexible hose appears damaged, turn off the local isolation valve if it is safe to do so and arrange professional assistance.
If a hose bursts, shut off the home’s main water supply if you can do so safely and contact an emergency plumber.
5. The Hot Water System Discharges More Than Expected
Hot water systems incorporate safety devices that manage pressure and temperature.
Some discharge during normal heating cycles, but continuous discharge or a significant change in discharge should be investigated.
Never cap, block or interfere with a relief-valve discharge pipe.
A plumber may need to check:
- Inlet water pressure
- Pressure-limiting valve
- Expansion controls
- Relief valves
- Hot water system operation
High pressure is only one possible explanation, so the entire system should be assessed.
6. Water Pressure Changes at Different Times
Water pressure can change because of network demand, elevation and other supply conditions.
A pressure-limiting valve should regulate the pressure downstream even when incoming supply conditions vary within its operating range.
If pressure changes significantly between morning, afternoon and evening, a plumber can test the system at different times.
A booster pump or another pressure-control device may also be contributing to the problem.
7. Your Water Usage Increases Without an Obvious Explanation
High water pressure itself does not appear as a separate item on your water bill.
However, higher pressure can increase the flow rate through an open outlet and may make existing leaks more significant.
If your water usage suddenly increases:
- Check taps and toilets for visible leaks.
- Check outdoor fixtures.
- Follow the water meter testing guidance provided by your water supplier.
- Arrange professional leak detection if the cause is unclear.
A plumber can investigate both potential leaks and water pressure without automatically assuming one caused the other.
Why Would a Pressure-Limiting Valve Stop Working Properly?
Several issues can affect a PLV.
These include:
- Sediment or debris
- Worn seals
- Spring deterioration
- Diaphragm wear
- Corrosion
- Incorrect installation
- Incorrect valve selection
- Changes to the plumbing system
However, the valve may not be the problem at all.
High incoming network pressure, a booster pump, thermal expansion or a faulty fixture can produce similar symptoms.
That is why high water pressure in house plumbing should be diagnosed with a pressure test rather than guessed from symptoms alone.
How Does a Plumber Test Water Pressure?
A licensed plumber can connect a suitable pressure gauge to an appropriate point in the plumbing system.
With outlets closed, the plumber can measure static pressure.
They may also take readings while water is flowing to assess pressure under demand.
Depending on the symptoms, the plumber may:
- Test static pressure
- Test dynamic pressure
- Compare pressure before and after the PLV
- Check hot and cold water
- Inspect the pressure-control equipment
- Test at different times
- Look for related plumbing faults
If excessive pressure is confirmed, the appropriate repair or replacement can be selected based on the plumbing system, incoming pressure, pipework and required downstream pressure.
Does the Pressure-Limiting Valve Need Repair or Replacement?
It depends on the valve and its condition.
Some pressure-control devices may be serviceable or adjustable according to the manufacturer’s requirements. Others may need replacement because of wear, damage or corrosion.
After servicing or replacement, the system should be retested to confirm that the pressure is being controlled correctly.
A plumber should also inspect vulnerable hoses, valves, fixtures and appliance connections where excessive pressure has been present.
Should You Remove the Valve for a Stronger Shower?
No.
Removing or bypassing a pressure-limiting valve can expose the plumbing system to excessive pressure and may create compliance and safety issues.
If your shower pressure is disappointing, the problem may instead be:
- A blocked showerhead
- A flow restriction
- A faulty tempering valve
- A hot water problem
- Blocked pipework
- An issue with the shower mixer
The objective should be safe and consistent water pressure, not simply the highest possible pressure.
Can You Check Water Pressure Yourself?
A suitable household pressure gauge connected to an appropriate outdoor tap can provide an initial static-pressure reading.
For the reading to be useful, other water outlets should generally be closed.
However, one reading may not identify:
- Intermittent pressure problems
- Pressure surges
- Dynamic pressure issues
- Problems affecting only part of the plumbing system
- Faulty pressure-control equipment
Do not dismantle, adjust or bypass the pressure-limiting valve yourself.
If you notice unusual pressure, record when it occurs and which fixtures are affected. This information can help a plumber diagnose the problem more efficiently.
Arrange a Pressure Check Before Damage Occurs
Noisy pipes, unusually forceful outlets, repeated leaks and stressed flexible hoses are all reasons to investigate your home’s water pressure.
These symptoms do not automatically mean the pressure-limiting valve has failed. However, testing the pressure can help identify whether excessive pressure is contributing to the problem.
Early diagnosis may help reduce unnecessary wear on plumbing fixtures and reduce the risk of a more disruptive leak.
If a pipe or hose has already burst, turn off the main water supply if it is safe to do so and seek emergency plumbing assistance.
For non-urgent concerns, arrange a professional pressure assessment before repeatedly replacing taps, hoses or other fixtures.
About Tai Irwin Plumbing and Draining
Tai Irwin Plumbing and Draining is a family-owned and operated plumbing company serving Sydney and surrounding suburbs since 1985.
The experienced team provides domestic and commercial plumbing services, including burst-pipe repairs, leaking tap and toilet repairs, hot water services, blocked-drain solutions and 24-hour emergency assistance across the Northern Beaches and North Shore.
Contact Tai Irwin Plumbing and Draining for a professional water-pressure assessment, practical advice and the appropriate solution for your home’s plumbing system.
