Low water pressure is one of the most frustrating plumbing problems — weak showers, slow-filling taps, and appliances that take forever to cycle. The first step in fixing it is working out whether the problem is localised to one fixture or affecting the whole house, because the causes are very different.
Is it localised or whole-house?
Before investigating, check whether the low pressure affects one fixture, several fixtures, or the entire house:
- One fixture only — likely a blocked aerator, a failing mixer cartridge, or a localised pipe issue.
- Hot water only — points to the hot water system, a tempering valve, or the hot water pipework.
- Whole house, hot and cold — points to the main supply: a pressure-limiting valve, the main shut-off valve, or the supply pipe from the street.
Common causes of localised low pressure
Blocked aerators
The aerator (the small screen at the end of the spout) catches sediment and mineral buildup over time. If one tap has low pressure while others are fine, unscrew the aerator, clean it, and see if the flow improves. This is one of the simplest fixes.
Failing mixer cartridges
In mixer taps, a worn or partially blocked cartridge can restrict flow. If cleaning the aerator doesn't help and the problem is isolated to one mixer, the cartridge may need replacing.
Localised pipe corrosion or blockage
A section of pipe with internal corrosion or a partial blockage can reduce flow to the fixtures downstream of it. This is more common in older homes with galvanised pipes.
Common causes of whole-house low pressure
A partially closed or faulty main shut-off valve
If the main valve isn't fully open, or is faulty and restricting flow, every fixture in the house will have reduced pressure. Check that the main valve is fully open. If it's stiff or won't turn fully, it may need servicing.
A pressure-limiting (pressure-reducing) valve
Some homes have a pressure-limiting valve on the main supply to protect fixtures from high mains pressure. If this valve is faulty or set too low, it can reduce pressure across the whole house. A plumber can test and adjust or replace it.
Older galvanised supply pipes
Many older Gold Coast homes have galvanised iron supply pipes that rust internally, narrowing the pipe and reducing flow. If your pressure has gradually declined over years and the water is sometimes discoloured, corroded pipes may be the cause. The only permanent fix is repiping. See our burst pipe and leak detection services for an assessment.
Hot water system issues
If only the hot water has low pressure, the hot water system, a faulty tempering valve, or a blockage in the hot water pipework may be the cause. A failing tempering valve is a common culprit — see our guide on why you might not have enough hot water
Leak on the main supply
A leak on the main supply pipe between the meter and the house reduces pressure to every fixture. If you suspect a leak, check the water meter with everything turned off — if it's still moving, you have a leak somewhere. See our guide on signs of a water leak
When to call a plumber
If cleaning aerators doesn't solve the problem, or if the low pressure affects the whole house, professional diagnosis is worthwhile. A plumber can test pressure at different points, check the main valve and pressure-limiting valve, and assess whether pipe corrosion is the cause. Contact our Gold Coast team for a pressure diagnosis.
Frequently Asked Questions
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