How to Fix Low Water Pressure at Home

Low water pressure makes showers feel weak and fills the washing machine slowly. The cause can be as simple as a clogged tap aerator or as involved as a leaking pipe.

Is it one tap or the whole house?

If only one tap is weak, the problem is local. Unscrew the aerator or the shower head and soak it in vinegar to remove scale. If the whole house is weak, look wider.

Check the main tap and isolation valves

A main stopcock that is partly closed will limit flow. Make sure it is fully open. Also check isolation valves under sinks and near the hot water unit.

Hot only or cold only?

If only hot water is weak, the hot water system, a valve or a blocked pipe could be at fault. If both are weak, it is likely supply or pipework.

Hidden leaks

A leak in the pipes can reduce pressure at the taps. Do the meter test with everything off. If the meter moves, call a plumber.

Old pipes

Galvanised pipes rust on the inside over the years, which narrows the pipe. Replacing them restores flow. Copper and plastic pipes do not have this problem in the same way.

Pressure reducing valves

A pressure limiting valve, where one is fitted, can wear out or be set too low. A plumber can test the pressure with a gauge and adjust or replace the valve.

Street supply issues

Sometimes the problem is outside your property. Ask neighbours if they have the same issue, and check your water authority for works in the area.

When to call us

If simple checks do not fix it, we can test pressure and trace the cause.

Check the flow at a single tap

Fill a bucket from the kitchen tap and time it. A healthy tap fills a ten litre bucket in around a minute, though it varies. If one tap is much slower than the rest, remove the aerator and look for grit. If every tap is slow, test them again with the hot water and cold separately.

Hot water system problems

A partly blocked hot water valve, a failing mixing valve or sediment in the tank can restrict hot flow. If cold is strong but hot is weak, the hot side is the place to look. Gas continuous flow units can also give weak flow if the filter on the cold inlet is clogged.

Pipes and fittings

Kinked flexible hoses, half-open isolation valves and old pipe sections with scale all cut flow. Small changes add up. A plumber can trace the pipe run and check each point. In older houses, replacing a corroded section often restores strong pressure right away.

Is the pressure actually too high instead?

High pressure causes problems too, such as banging pipes and short tap life. A pressure gauge on an outdoor tap shows the real number. Your plumber can fit or adjust a pressure limiting valve to protect your fittings.

Booster pumps

If your supply pressure is low because of your location or a tall building, a booster pump can help, but it will not fix a leak or a blocked pipe. Find the cause before buying one.

Start with what changed

Low pressure is annoying, but the most useful question is what changed. If the shower was fine last month and weak this month, something changed in the house, the street or the tap. Did a plumber or builder work on the house recently? Did the water get switched off for works in your street? Did the hot water system get replaced? A valve left partly closed after any of those jobs is one of the most common causes of low pressure, and it costs nothing to check.

Write down what you see. Is it every tap or one? Hot, cold or both? All day or only in the evening? That information narrows the cause fast and saves you paying for a plumber to rediscover it.

The slow checks homeowners can do safely

At a single tap, unscrew the tap outlet and look at the little mesh aerator. Sediment and scale clog it and the flow drops. Soak it in vinegar, rinse it and put it back. In the shower, the head clogs the same way. Both take minutes.

For the whole house, check the main tap and any isolation valves are fully open. Look at the water meter with every tap off. If the dial moves, you have a leak, and a leak can drop pressure. Ask neighbours if they have noticed the same thing. If they have, call your water authority before calling a plumber, as the fault may be on the supply side.

If none of that helps, a plumber can test pressure at the meter and at a tap and tell you where it falls. That one reading usually points straight at a failing pressure limiting valve, a blocked pipe or a supply problem.

When low pressure is a safety or health issue

Most low pressure is just annoying. It becomes a different problem if you lose water entirely, if the water runs brown after a burst main or if hot water pressure drops sharply on a gas system, which can point to a fault with the unit. A sudden loss of pressure at every tap with a wet patch in the garden can mean a broken pipe between the meter and the house.

If your water suddenly stops, check whether your neighbours have water. If they do not, it is probably a street issue and your water authority can tell you what is happening. If they do, the fault is yours, and the first step is the main tap and meter.

Questions to answer before you call a plumber

Is it hot, cold or both? One tap or all? Did it start suddenly or slowly? Is the outside tap also weak? Do neighbours have the same problem? Did anything change recently, such as plumbing work, street works or a new appliance? The answers narrow the cause quickly and save diagnostic time.

If the problem is only at one tap, the plumber can often fix it on the spot. If it is the whole house, expect a pressure test and a check of the main tap, the pressure limiting valve and the pipework.

Talk to GSA Plumbing Services

We work across Geelong and Melbourne, 24 hours a day, 7 days a week. Call 0401 041 103 or use the contact page. Quotes are free and there is no call-out fee.