Why did my water pressure suddenly drop?

Is it the whole house or one tap?

First, check more than one tap, hot and cold, upstairs and down. If it’s just one outlet, the problem is at that tap (a blocked aerator or a partly-closed valve), not your supply. If every outlet is weak, it’s a supply, filter, or pump issue, so keep going.

Work from the street in

• Check your main stop tap (at the meter or where the water enters) is fully open. A half-closed stop tap after recent work is more common than it sounds.
• Ask a neighbour or check for notices, your water authority may have a burst main or planned work reducing pressure in the street.
• If you have whole-house filters, check them. A clogged cartridge chokes flow and drops pressure across the house.
• Look for a leak. A big leak or a stuck-open valve bleeds pressure away, check for wet patches, a meter still ticking with everything off, or the sound of water.
• On tank or bore water, the pressure comes from your pump. A pump that has lost prime, tripped, or faulted will drop your pressure, check it’s running (see our pump guides).

If nothing obvious turns up

A pressure-reducing valve that has failed, or a partly-blocked pipe, can drop pressure with no obvious cause. If you have worked through the above and it’s still weak everywhere, that’s the point to call a plumber, and it’s worth knowing whether a booster pump is the right long-term answer.

When low pressure is just how your supply is

If your pressure is low all the time rather than a sudden drop, the fix is usually a pressure pump that lifts it to a strong, steady level across every tap and holds a pressure you set. A Grewa Boost pump does exactly that. If you aren’t sure whether that’s your situation, our quick quiz sorts it in a minute.

Common questions

It dropped only on the hot side, what does that mean?

If only hot water is weak, the issue is on the hot side, often the hot water system or a tempering valve, not your main supply. We have a separate guide on low hot-water pressure.

Pressure is fine in the morning but drops in the evening, why?

That’s usually peak demand, lots of homes drawing at once lowers street pressure at busy times. A booster pump evens that out so your pressure stays steady regardless.