Low water pressure usually comes down to one of four things: a blocked or worn tap or shower head, a stop tap or pressure limiting valve that isn’t doing its job, a leak, or old galvanised pipe that has rusted up inside. On tank water, it’s usually the pump or the filter in front of it. Start by working out whether it’s one tap or the whole house, because that tells you where to look.
One tap or the whole house?
- One tap or one shower. The problem is at that fitting. The aerator on the end of a kitchen or basin tap and the holes in a shower head clog with grit and scale, and mixer cartridges wear out. Unscrew and rinse the aerator first. If that doesn’t fix it, the tap or mixer needs a repair.
- Hot side only. If the cold runs well and the hot is weak, the problem is likely at the hot water unit or the valves on it, such as the tempering valve. That one is for a plumber.
- Every tap in the house. The cause is further back: the stop tap, the pressure limiting valve, a leak, the pipes themselves or the supply. Read on.
On mains water: the checks to do first
SA Water’s advice for low pressure is to check the plumbing at your own property first.
- Is the stop tap fully open? If your house has an internal stop tap, check it’s turned all the way on. It’s easy to leave one half closed after a repair.
- Any works in the street? Planned works and main breaks can drop pressure for a while. SA Water’s faults and outages map shows what’s happening near you.
- Is the meter moving? Turn off every tap and anything that uses water, then look at the meter. If the numbers are still moving, water is going somewhere it shouldn’t.
- Do the flow test. SA Water aims to supply at least about 27 litres a minute at the meter. With everything off, write down the last three red numbers on the meter, run the front garden tap fully for one minute, then read the meter again. Less than 27 litres, and nothing wrong on your side? Report it to SA Water on 1300 729 283.
Where you are matters too. SA Water says pressure depends on things like whether you’re at the top or bottom of a hill and how far you are from a reservoir, storage tank or main. On the hilly edges of the Barossa, two houses in the same town can get quite different pressure.
The pressure limiting valve
A pressure limiting valve (PLV) sits near the meter and stops mains pressure getting high enough to damage pipes and appliances. SA Water says that since November 2005 the plumbing standard has required one on new connections where the pressure is over 500 kPa, so a lot of homes built since then have one. PLVs can fail, and a faulty one is one of the causes of low pressure SA Water lists. Checking and replacing a PLV is a job for a licensed plumber.
It works the other way too. If your home was built before 2005 and the pressure inside is over 500 kPa, SA Water recommends getting a plumber to fit a PLV to protect the pipes and appliances. Pipes that bang when a tap shuts off can be a sign of high pressure or a sudden change in it.
Old galvanised pipe
Plenty of older houses still have galvanised steel water pipe. Over the years it rusts on the inside, the pipe narrows and the pressure drops, often with brown water when a tap first runs. It turns up in the old stone homes around Angaston and in the older streets of Gawler. Flushing won’t fix rusted galv: the fix is new pipe. For a bigger re-pipe, Craig comes out and looks first, so the quote is based on what’s actually there.
Pressure dropped suddenly and you can hear water running? Ring Craig on 0499 319 297.
On tank water
On rural blocks around the Barossa, the pressure comes from the pump, not the mains. When tank water is weak, look at:
- The filter in front of the pump. A blocked one starves the pump.
- The pump itself. Cycling on and off when nobody is using water, running without stopping, or not starting at all are all signs it needs looking at.
- Air in the line. Taps that spit air can mean a low tank or a leak on the suction side.
- The size of the pump. A pump that is too small for the house shows up when two taps run at once.
Craig tests the pump first, and tells you whether it’s worth repairing. More in our post on plumbing a rainwater tank into your house and on our rainwater tanks and pumps page.
Hidden leaks
A leak under the floor, in a wall or out in the yard steals pressure as well as water. Signs to look for: the meter moving with everything turned off, a damp patch that won’t dry, a strip of lawn that stays green or soggy, or a water bill that jumps. Craig finds and repairs leaks in walls and under floors before they do more damage. If a pipe has burst, turn the water off at the meter first. Our post on what to do with a burst pipe covers the first few minutes.
What Craig does
Craig works through it in order: the taps and shower heads, the stop tap and PLV, the meter for leaks, then the pipework or the pump. You’ll hear what’s causing it and know the price before any work starts. Small jobs are welcome, and our general plumbing page lists the everyday repairs.
We’re based in Williamstown and work right across the Barossa Valley, Gawler and surrounds, including Gawler, Angaston and Tanunda. Ring Craig on 0499 319 297, call Hayley in the office on (08) 8472 9507, or send us the details.
Sources
Rules and schemes change. These sources were last checked on 3 November 2026. Licence: LIC PGE341299.
More from the blog
- Gas bayonet points for BBQs and heaters: what to know before you book
- Hydro jetting in Tanunda and Nuriootpa: how it clears a blocked drain
- Blocked drains and tree roots: signs, causes and fixes
- CCTV drain inspections: what the camera shows and when you need one
- Stormwater drainage problems: pooling water, overflowing pits and blocked downpipes
- How often should a septic tank be pumped out in the Barossa?
- Gas leak or burst pipe: what to do before the plumber arrives
- No hot water? What to check first, and when to call a plumber
- Heat pump, gas or solar hot water: which suits a Barossa home?
- Plumbing a rainwater tank into your house in SA
- Bathroom renovations in the Barossa: how the plumbing side works
