Why is my water pressure low?

Flow is being restricted somewhere between the supply and the tap. Whether it's one fixture or all of them is the key diagnostic split.

• 01
  Clogged aerator

  Mineral scale collects in the screen at the tip of the faucet. The most common single-fixture cause.

• 02
  Failing pressure regulator

  A worn regulator can drop pressure across the whole house, often gradually.

• 03
  Partly closed main valve

  Frequently overlooked after plumbing work — the valve was never fully reopened.

• 04
  Corroded galvanised pipes

  In older homes, internal corrosion narrows pipes over decades.

• 05
  Hidden leak

  A leak reduces pressure and wastes water. Suspect this if pressure dropped suddenly.

• 06
  Municipal supply issue

  Worth ruling out by asking a neighbour whether they've noticed the same thing.

1. 1Determine whether it's one fixture or the whole house — this decides everything
2. 2Unscrew the faucet aerator and soak it in vinegar to dissolve scale, then rinse and refit
3. 3Check that the main shutoff valve is fully open
4. 4Check the water meter with everything off; if it's still moving, you likely have a leak
5. 5Ask a neighbour whether their pressure changed too

Call if the whole house is affected, if the meter moves with all water off, or if you have older galvanised piping.

$150–$900

Aerator and cartridge work is minimal. Pressure regulator replacement is mid-range. Repiping is a much larger project quoted separately.

Estimates are typical US ranges for orientation. Actual pricing varies by region, home and contractor — always get a written quote.

If low pressure is caused by a hidden leak, the water is going somewhere — often into framing or a slab, where it causes expensive damage and can support mould.

• Is this one fixture or system-wide?
• What's my measured static pressure?
• Is the pressure regulator working correctly?
• Any evidence of a hidden leak?