Low water pressure can make showers weak, taps slow and everyday plumbing frustrating. The fastest way to narrow down the cause is to check whether the problem affects one outlet, several outlets or the entire property.
A sudden change in water pressure can have a very different cause from pressure that has always been poor. Start by comparing different taps and asking whether neighbours are experiencing the same issue.
Try the cold kitchen tap, bathroom basin, bath tap, shower and taps on different floors. If only one outlet is weak, the problem is probably local to that fitting. If every outlet has reduced pressure, investigate the main supply, stop valve or wider plumbing.
A single weak tap can be caused by a blocked aerator, limescale, faulty cartridge, partially closed isolation valve, flexible hose restriction or debris inside the fitting.
Unscrew and clean the tap aerator if it is designed to be homeowner-removable. Mineral deposits can restrict the small openings and noticeably reduce flow.
Showers often make pressure problems most obvious. Possible causes include a blocked shower head, limescale in the hose, mixer valve issues, incompatible shower type, low incoming mains pressure or pump problems.
Remove and clean the shower head according to the manufacturer’s instructions. If pressure is strong at nearby taps but poor only at the shower, the shower itself becomes a more likely source.
If every tap is weak, check whether the change happened suddenly. Possible causes include a partially closed internal stop valve, external supply issue, water-main work nearby, a leak, restricted old pipework or a pressure regulator problem where fitted.
Ask a neighbour whether their water pressure has also fallen. If several nearby properties are affected, the issue may be with the water network rather than your internal plumbing.
The internal stop valve is often located beneath the kitchen sink, although locations vary. If it has been partially closed during plumbing work, water flow throughout the property can be reduced.
Do not force a seized valve. Old stop valves can leak or break if excessive force is applied.
A significant leak can reduce pressure and may not always be immediately visible. Look for damp patches, unexplained water sounds, wet floors, water staining or reduced pressure that appeared suddenly.
Older pipework can also become restricted internally. A plumber can compare flow at different points to help determine where the restriction is occurring.
Compare hot and cold water, check the cold kitchen tap, ask neighbours, check the stop valve, clean aerators and shower heads and look for visible leaks.
These are different problems. Low household water pressure affects water coming from taps and showers. Low boiler pressure refers to the sealed central-heating circuit inside many boiler systems.
For heating-system pressure problems, see Why Is My Boiler Losing Pressure?
Contact your water supplier when neighbours are affected too, pressure suddenly falls across the property, there is no water at all or you suspect network work or a burst main.
Call a plumber when only your property is affected, the stop valve is damaged, a leak is suspected, pressure is poor at multiple internal outlets, pipe restrictions are suspected or pressure has gradually worsened.
TES Heating provides plumbing diagnostics across London for low water pressure, leaking pipework, taps, valves and related problems.
A sudden change can result from water-main work, a leak, a partially closed valve or another supply problem.
A blocked shower head, hose, mixer valve or shower-specific restriction may be responsible.
Yes. Limescale can restrict tap aerators, shower heads and internal fittings.
No. Household water pressure and sealed heating-system pressure are separate measurements.
If neighbours are affected, contact your water supplier. If only your property is affected, a plumber can investigate the internal system.
