Why Is My Water Pressure Low?
Low water pressure is caused by clogged pipes, a faulty pump, a partially closed valve, a hidden leak or an issue with the main supply. The cause can be isolated to a single fixture or affect the whole property, which points to where the problem is.
If only one tap or shower has low pressure, the fault is usually local — a clogged aerator or a partially closed fixture valve. If pressure is low throughout the property, the cause is more likely the pump, the main valve or the supply line itself.
Common Causes
- Clogged pipes or fixtures — mineral scale or debris narrows the flow inside pipes, aerators or shower heads.
- Faulty booster pump — a worn or failing pump cannot maintain pressure across the property.
- Partially closed valve — a main or isolation valve not fully open restricts flow without being obvious.
- Hidden leak — a leak diverts water before it reaches the fixture, lowering pressure at the tap.
- Low tank level — a water tank running low or with a faulty float valve reduces supply pressure.
Single Fixture vs. Whole-Property Pressure Loss
| Pattern | Likely Cause |
|---|---|
| Low pressure at one tap or shower | Clogged aerator, shower head or local fixture valve |
| Low pressure throughout the property | Booster pump fault, main valve issue, or a leak in the main line |
| Pressure drops gradually over weeks | Scale buildup or a slow-developing leak |
| Pressure drops suddenly | Valve closed, pump failure, or a new leak |
When to Call a Plumber
Whole-property pressure loss usually needs a water pump check or main line inspection rather than a fixture-level fix. If cleaning an aerator or shower head doesn’t resolve single-fixture pressure loss, the fault is likely further back in the line.