Low Water Pressure.Done Right.

Is it the whole house or one tap?

If one tap is weak, the cause is often a blocked aerator or cartridge. If the whole house is weak, check that the main tap is fully open, then look at the meter, any filters and the pressure limiting valve. Compare hot and cold. If only the hot is weak, the hot water system or its pipework may be the cause.

Mains pressure and your water retailer

Mains pressure varies with the time of day, the height of your property and how many neighbours are using water. If pressure is low along your street, contact your water retailer. A plumber can measure pressure at a tap with a gauge to show what you actually receive.

Old pipes, scale and valves

In older houses galvanised pipes can corrode inside and narrow, which cuts flow. Partly closed valves, blocked strainers and failing pressure limiting valves also reduce pressure. A plumber works through these in order, starting with the simplest and cheapest tests.

When pressure is too high

Very high pressure stresses pipes, taps and appliances and can cause banging pipes and leaks. A pressure limiting valve fitted near the meter keeps pressure in a safe range. If your taps hammer or your relief valve drips often, ask for a pressure test.

Pumps and boosters

A pump can lift pressure from a tank or a weak supply, but it does not fix a narrowed pipe. A pump also needs the right size, placement and controls. Ask what the pump will fix and what it will not, before you buy one.

Filters, strainers and valves

Taps and appliances have small strainers that catch grit, and they clog. A partly closed isolation valve, a blocked filter or a failing pressure limiting valve can also cut flow. A plumber tests these in turn, since each is a cheap fix compared with replacing pipes.

Hot water only

If cold pressure is fine but hot is weak, look at the hot water system: a partly closed valve, scale in the tank or pipework, a blocked tempering valve or an undersized pipe. Older storage systems collect sediment that restricts flow.

Testing and recording pressure

A pressure gauge on an outside tap shows the static pressure at your property. Measure at different times of day, since evening demand can lower pressure. Write down the figures and give them to your water retailer or plumber.

Questions people ask about low pressure

Is low pressure my plumber's problem or the retailer's?

A gauge test at your meter shows which. Low pressure that shows up at the street is usually something to raise with your water retailer, while problems in the pipes and fittings inside your property are for a plumber.

Will a pump fix it?

Only if the cause is a weak supply. It does not repair a blocked pipe.

Why did my pressure drop suddenly?

Check for works in the street, a partly closed valve or a new leak.

Can scale be removed?

Aerators can be descaled. Scaled pipes usually need replacing.

A step-by-step check you can do first

Check whether the main tap is fully open and whether other taps or the neighbours are affected. Unscrew the tap aerator and look for grit and scale. Check the isolation valves under the sink are fully open. Try the outside tap, which bypasses most of the house pipework, to see whether the problem is the street supply or your pipes. Write down what you find and give it to the plumber, because the results narrow the cause quickly.

Replacing pipework: what is involved

Where old galvanised or corroded pipe is the cause, replacement may be a section or the whole house. Modern pipe is lighter and does not corrode in the same way, and it can often be run through the roof space or walls with limited disruption. Ask for the route, the work to make good and what warranty applies. Compare it with the cost of living with poor pressure for years.

Pressure limiting valves and why they fail

Many homes have a pressure limiting valve that protects pipes and appliances from high street pressure. When it wears out it can restrict flow, causing low pressure throughout the house, or it can fail open and let pressure surge. Replacing it is a short job, but the first step is to measure pressure with a gauge on an outside tap.

A reading that is low at the tap and normal at the street supply points to the valve or the pipework. A reading that is low everywhere suggests the supply problem is outside your property, and your water retailer is the one to ask.

Hot water pressure that is lower than cold

If cold water is strong but hot is weak, the cause is usually in the hot water system or its pipework. Sediment in a tank, a partly closed valve, a blocked tempering valve or scaled pipes can all restrict the hot side. Mixer taps may also be affected by a worn cartridge or a blocked filter screen.

Note whether the weak hot water happens at every tap or only one. This tells the plumber whether to look at the system or at a single fitting, and it avoids replacing parts that are not at fault.

When low pressure is a sign of a leak

A leak can drop pressure, particularly a large one on the supply side. If pressure dropped suddenly and your meter moves when everything is off, there may be a leak in the supply pipe. Check the area between the meter and the house for wet ground.

Turn off the main tap and call a plumber if you find wet ground or hear water running.

Guides worth reading

• How to Find a Hidden Water Leak in Your Home
• How to Fix Low Water Pressure at Home
• Plumbing Problems in Older Homes: What to Look For Before They Cost You

Related plumbing services

• Leaking Taps: Dripping taps fixed with new washers, cartridges or full replacement.
• Tap and Mixer Installation: New kitchen, bathroom and laundry taps and mixers fitted properly.
• Toilet Repairs and Installation: Running, leaking and faulty toilets repaired, plus new toilet installation.
• Shower Repairs: Leaking, dripping and low-flow showers repaired.
• Emergency plumbing is available 24 hours a day, 7 days a week

Talk to GSA Plumbing Services

Call 0401 041 103 or send an enquiry on the contact page. We work across Geelong, Melbourne and surrounding suburbs.