Why Do I Have Low Water Pressure Even Though the Water Is On?
25 May 2026 · Plumbers On Duty
Weak water pressure makes showers frustrating and filling a pot feel like it takes forever. The causes range from a simple clogged aerator to a municipal supply problem, and some are surprisingly easy to overlook. Here is how to work through it methodically.
First, rule out the obvious
Check whether the water has been shut off. Plumbers are regularly called to homes with no pressure only to find the municipal supply was cut, sometimes due to a payment issue or local maintenance. Before assuming a plumbing fault, confirm your supply is on at the mains and the municipal level.
Then check whether the problem affects one tap or the whole house. A single slow tap points to that fixture; whole-house low pressure points to the supply or main valve.
Common causes of low pressure
- Clogged aerators. Mineral and sediment build-up in the small screen at the tap tip is one of the easiest fixes. Unscrew and clean it.
- A partially closed shut-off valve. If a main or fixture valve is not fully open, flow is restricted.
- Sediment build-up in pipes. Over time, scale and sediment narrow older pipes.
- A clogged flow restrictor, common in shower heads in hard-water areas.
When it's more serious
Whole-house low pressure that appears suddenly can point to a hidden leak or a burst pipe in the walls, which is a more serious problem requiring a plumber for water pressure issues.
If you live in an area with naturally low municipal pressure, running many appliances at once can leave them underperforming even though no fault exists.
Frequently asked questions
Why do I suddenly have no water pressure? First check that your municipal supply has not been cut and that your main valve is fully open. Sudden whole-house pressure loss can also indicate a hidden leak or burst pipe.
How do I fix low pressure at one tap? Often it is a clogged aerator. Unscrew the small screen at the tap tip, clean out the mineral build-up and refit it.
Can low water pressure damage my pipes? Low pressure itself is unlikely to damage pipes. But the underlying cause, such as a hidden leak, can cause damage and should be investigated.
Sources
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