What Causes Low Water Pressure?

Low water pressure is frustrating and can point to anything from a simple blockage to a more significant plumbing issue. Working out whether it's affecting one fixture or the whole house is the first useful step.

Isolated to one tap or fixture

If only one tap or showerhead has reduced pressure, the cause is often a partially blocked aerator or showerhead, or a fault with that specific fixture. Cleaning or replacing the fixture usually resolves it.

Affecting the whole house

Whole-house low pressure points to a bigger cause: a partially closed main shut-off valve, a leak somewhere in the system reducing pressure elsewhere, corroded pipes narrowing water flow, or in some cases an issue with the water main supplying the property.

Ageing or corroded pipes

Older galvanised steel pipes can corrode internally over decades, gradually narrowing the space water flows through. This tends to develop slowly, so pressure loss can be gradual enough that it's not immediately obvious until it's fairly advanced.

A hidden leak

A leak elsewhere in the system, inside a wall, under a slab, or underground, can reduce pressure at your fixtures while also wasting water and potentially causing damage. If low pressure comes with a higher than usual water bill or damp patches somewhere in the property, a leak is worth investigating.

When to call a plumber

If pressure loss is sudden, affects the whole house, or comes with other signs like damp patches or unusual water bills, it's worth getting a plumber to assess the system rather than assuming it will resolve on its own.