Water pressure dropped off? Let us find out why.

Low water pressure is one of the most common things people call us about. The cause can be anything from something you sort out yourself in five minutes to something that genuinely needs a plumber. The good news is that you can usually narrow it down a fair way before anyone comes out. Here is how we think through it.

First, is it pressure or flow?

People say "low pressure" for two slightly different things. Pressure is the force behind the water. Flow is how much water actually comes out over time. A tap can have decent pressure but poor flow if something is restricting it, and the fixes are not always the same. You do not need to get technical about it, but keeping the difference in mind helps when you describe the problem to a plumber.

Is it one tap, or the whole house?

This is the single most useful thing you can check, and it costs you nothing. Go around the house and try a few taps and showers, both hot and cold. If only one fixture is weak, the problem is almost certainly local to that tap or shower. If everything is weak across the house, you are looking at something on the main supply side. That one observation narrows the search enormously.

If it is just one tap or shower

When the trouble is at a single fixture, the usual suspects are:

• A clogged aerator. The little screen on the end of a tap collects mineral build up over time. You can often unscrew it, give it a clean, and get your flow straight back.
• A scaled up shower head. Same idea as the aerator. Soaking or replacing the shower head can make a big difference.
• A worn tap cartridge or washer. Internal parts wear out and restrict flow. A simple part replacement usually sorts it.
• An isolation valve that is not fully open. The small valve under a sink or behind an appliance can get knocked or left part closed after other work.

If it is the whole house

When every tap is weak, the cause is further up the line:

• The main stop tap is not fully open. After any plumbing work, the main tap sometimes gets left partly closed. It is worth checking it is turned all the way on.
• A failing pressure limiting valve. Many homes have a valve that keeps incoming pressure at a safe level. They have a lifespan, and when they start to fail the pressure can drop off across the house.
• Old galvanised pipes. In older homes, steel pipes corrode and narrow on the inside over the years, which chokes the flow. This one often comes with discoloured water.
• A leak on the line. Water escaping somewhere before it reaches your taps can show up as a pressure drop.
• Mains supply. Pressure from the street can vary, especially at busy times of the morning and evening.

Canberra things worth knowing

Canberra's water network, run by Icon Water, delivers different pressures depending on your suburb and how high up you are. Homes on higher ground or at the end of a supply run can naturally see lower pressure, particularly at peak times. Add in the older inner suburb homes with ageing pipework, and a few cold Canberra winters, and it is easy to see why pressure complaints are common here.

What you can check yourself before calling

Before you get anyone out, a few quick checks will either fix the problem or tell a plumber a lot:

1. Work out whether it is one fixture or the whole house.
2. Clean the aerator on the affected tap, or the shower head.
3. Make sure the main stop tap and the tap at your water meter are fully open.
4. Ask a neighbour whether their pressure is low too. If it is, the issue is likely on the mains rather than your home.
5. Note whether the drop was sudden or came on gradually. Sudden changes matter, as below.

When it is time to call a plumber

Give us a call, or another licensed plumber, if:

• The pressure dropped suddenly across the whole house. That can point to a burst or a leak, and you may be losing water, so it is worth acting quickly. If you suspect a burst, our guide on when to call an emergency plumber is a good next read.
• Only the hot water is weak. That usually points to the hot water unit or one of its valves.
• The pressure is still off after the simple checks above.
• You have discoloured water along with the low pressure, which can suggest corroded pipes.

There is no need to put up with a weak shower forever. If you have had a go and it is still not right, we are always happy to help you get to the bottom of it.