No Water Pressure in the Whole House? Work Through This List
One weak tap is a fixture problem. Weak pressure everywhere at once is a supply problem, and there are only a handful of causes. Working through them in order saves you a call-out you didn't need.
Start Outside at the Meter
Check the isolation valve next to your water meter is fully open. Partially closed mains taps are the single most common cause of sudden whole-house pressure loss — often after recent plumbing work or a meter replacement.
Check for Local Works
Urban Utilities publishes planned and unplanned outages. A mains repair or hydrant flush in your street will drop pressure temporarily. Ask a neighbour — if they've lost pressure too, it isn't your plumbing.
Look at the Pressure Limiting Valve
Most Brisbane homes built or re-plumbed since the 1990s have a pressure limiting valve at the meter. These have a service life of about 8–12 years and fail closed as often as they fail open. A failed PLV throttles the whole house and is a straightforward replacement.
Rule Out a Hidden Leak
Turn everything off and watch the meter. If it's still ticking over, water is escaping somewhere — under the slab, in a wall, or in the yard. A significant underground leak bleeds off enough pressure to affect the whole house.
Consider Pipe Corrosion
In pre-1970s Brisbane homes with original galvanised steel supply, internal rust scale narrows the pipe bore over decades. The give-away is pressure that's been declining gradually for years rather than dropping overnight, plus rusty water on first draw.
Hot Water Only?
If cold pressure is fine and only hot is weak, the problem is in the hot water system — usually a blocked tempering valve, a partially closed isolation valve on the unit, or sediment in the tank outlet.
Frequently Asked Questions
What is normal mains pressure in Brisbane?
Typically around 350–500 kPa at the property. Most plumbing fixtures are designed for a maximum of 500 kPa, which is why pressure limiting valves are fitted.
Can I replace a pressure limiting valve myself?
No — it's licensed plumbing work in Queensland, and getting the pressure setting wrong can damage fixtures and void warranties.
Would a water filter cause low pressure?
Yes. A clogged whole-house filter cartridge is a frequently missed cause. Check when it was last changed.