How can I tell if my water pressure is too high?
Your plumbing tells on itself. The common symptoms are pipes that bang or shudder when a tap or the washing machine shuts off, taps that spit and splash hard enough to soak the bench, a hot water relief valve that drips constantly onto the ground, and braided flexi hoses that keep failing years short of their expected life. Toilets that whistle or scream while filling are another giveaway, because their inlet valves are throttling far more pressure than they were designed for. None of these prove the number on their own. The proof is a pressure gauge, a cheap tool we carry on every job. Screwed onto a garden tap or the washing machine tap, it gives a static reading in seconds, and we take that reading on almost every callout, because it changes the advice we give about everything downstream of the meter.
What do the pressure numbers actually mean?
Static readings sort neatly into bands, and the 500 kPa figure from AS/NZS 3500 is the line that matters.
| Static pressure reading | What it means | What to do |
|---|---|---|
| Under 200 kPa | Low pressure, weak showers, slow-filling appliances | Investigate a supply restriction or old internal pipework |
| 200 to 500 kPa | The healthy band, and the AS/NZS 3500 limit for new installations | Nothing. This is where you want to be |
| 500 to 700 kPa | Above the new-installation limit, quietly shortening the life of hoses, tapware and hot water valves | Fit a pressure limiting valve, especially before new tapware or a new hot water system goes in |
| Over 700 kPa | Well into damage territory, where bursts and valve failures become a matter of time | Fit a limiting valve promptly and replace aged flexi hoses at the same visit |
One reading is a snapshot, not the whole story. Mains pressure rises overnight when demand across the network falls, so a house that reads 550 kPa in the afternoon can sit comfortably over 600 kPa at 3 am, which is exactly when flexi hoses like to let go.
Why does the Gold Coast have high-pressure pockets?
Because water networks are pressurised to serve the highest properties in each supply zone, and everyone below them wears the surplus. The Gold Coast runs from beachfront flats to steep hillside estates, and reservoirs and pumping zones are set so the homes at the top of each zone still get a decent shower. If your house sits low in its zone, at the bottom of a hill or on the flat below elevated streets, gravity adds pressure the network never trims off for you. The pattern we see is consistent: the homes where we replace burst flexis and weeping relief valves cluster in the low ground of their supply zones, while their uphill neighbours test fine. We are not going to name streets, because pressure genuinely varies house to house, but if the neighbours mention banging pipes too, your street likely sits in one of those pockets, and a two-minute gauge test settles it.
What does a pressure limiting valve do, and when is one required?
A pressure limiting valve, or PLV, is a small brass valve installed on your water service, usually just after the meter, that caps the pressure to everything downstream at a set figure no matter what the mains delivers. Feed it 800 kPa and it hands your house 500. AS/NZS 3500 requires new installations to be limited to 500 kPa, which is why new builds get a PLV as standard wherever mains pressure runs higher. The requirement reaches existing homes whenever significant new work is done: most hot water system manufacturers require pressure limiting for the warranty to hold, so we fit or verify a PLV as part of every hot water installation. No rule forces an older, untouched home to retrofit one, but the 500 kPa figure exists because every hose, cartridge and valve in your home is engineered around it, and running well above that number runs everything outside its design envelope.
What damage does high pressure actually cause?
The damage list matches our repair bookings. Burst flexi hoses top it. The braided hoses under sinks, vanities and toilets are the weakest point in the system, they fail without warning, and they fail indoors, where one hose can flood a home overnight. The hoses themselves cost $20 to $40 a hose at trade rates, which makes the flood the expensive part. Tapware comes second: ceramic discs, washers and mixer cartridges all wear against the pressure behind them, so taps in high-pressure homes drip sooner and need work more often, with a tap repair running $80 to $180 plus parts as of 2026. Hot water systems suffer twice, through relief valves that dribble constantly to shed excess pressure and through tanks cycling under stress they were not built for. And when a fitting or joint finally gives way, an accessible burst repair runs $250 to $650 plus parts. High pressure rarely breaks anything today. It shortens the life of everything, and that costs more.
How do we fix it, and what does it cost?
Usually with a single valve. We confirm the problem with a gauge reading, then supply and install a pressure limiting valve sized for your service, normally at the meter or where the main enters the house. We price PLV supply and install as a quote on inspection rather than a flat figure, because valve size, service material and access vary too much between homes for one honest number, and we would rather measure than guess. The quote is fixed before we start, like everything we do. While the water is off we check the age and condition of your flexi hoses, because hoses that have spent years above 500 kPa have used up life they cannot get back, and swapping tired ones at $20 to $40 a hose at trade is the cheapest part of the visit. If pressure has already claimed a casualty, a burst pipe or a relief valve that will not stop weeping, we repair it in the same visit under the same fixed quote.
Banging pipes, a dripping relief valve or a flexi that let go? Call Hills Plumbing & Gas on 0472 657 042 or book at /services/burst-pipe-repairs/. QBCC licence 15243081, gauge test on arrival, fixed price before we start.
Sources: AS/NZS 3500 plumbing and drainage standards (500 kPa limit for new installations); Queensland Building and Construction Commission (licensed plumbing work requirements).