Plumbing & water
Low water pressure: causes and fixes
Low water pressure is a geography problem. One weak tap, one weak floor, a weak house and a weak street have four different causes, and you can separate them in five minutes without a single tool.
By the Tickover team · Published 6 May 2026 · 4 min read
One distinction first: pressure is how hard the water pushes, flow is how many litres arrive per minute. A kinked or furred pipe can wreck flow while pressure reads fine, and what you feel at the tap is mostly flow.
Work outward from the tap
Where does the weakness live?
One tap: almost always the aerator, the little mesh at the spout tip, silted up with limescale and grit. Second suspect is the isolation valve under the fitting, nudged half-shut during a past repair. One floor: upstairs-only weakness usually means a gravity-fed system, where pressure depends on the height of the loft tank: a design limit, not a fault.
Whole house: if it arrived after plumbing work, someone left the stopcock half-open: open it fully, then ease back a quarter turn. Otherwise suspect a hidden leak, a failing pressure reducing valve if you have one, or a furred-up old supply pipe. Whole street: ask a neighbour, then check the company’s incident map.
The five-minute aerator clean
Fix the one-weak-tap case
Unscrew the aerator
The tip of the spout unscrews by hand, or with a cloth and gentle pliers. Some pull or lever out instead.
Lay the parts out in order
Mesh, washer, housing. They go back the same way, and the washer decides whether it drips afterwards.
Soak in white vinegar
Half an hour dissolves most limescale. Warm vinegar works faster.
Brush out the grit
An old toothbrush across the mesh, a rinse, and a squint through it at the light to confirm it is clear.
Refit and compare
Screw it back hand-tight and test. If flow is still poor, the isolation valve or the tap itself is next in line.
What your water company owes you
Water companies must maintain a minimum pressure at the boundary stop valve, roughly 0.7 bar (seven metres of head), and most work to healthier guideline flows. A kitchen cold tap in decent health fills a one-litre jug in about six seconds; if yours takes double that, ask for a pressure test, which is generally free.
10L/min
a common guideline flow for kitchen taps
0.7 bar
minimum mains pressure at your boundary
6 sec
a healthy tap fills a litre jug this fast
Before you call anyone
- Compare hot and cold at the same tap
- Try taps upstairs and down, note the pattern
- Check the stopcock is fully open, then back a quarter turn
- Check isolation valves under the affected fittings
- Ask a neighbour, or check the company incident map
- Time a litre jug at the kitchen cold tap
- Note whether mornings and evenings are worse (peak demand)
- Run the meter leak test with everything off
If only the hot side is weak, think limescale in a combi’s plate heat exchanger or the limits of a hot water cylinder system; anything inside the boiler casing is work for a Gas Safe registered engineer. If the complaint is really one room, the shower guide covers where weak flow hurts most.
Not sure what you’re dealing with?
Run the pattern through Self-Diagnose: which taps, which floors, hot or cold. It will name the likely cause and, if it is not a DIY one, brief a vetted plumber with the details.
Curing a persistent drip belongs in the same session: see fixing a dripping tap. For the wider system, start with the home plumbing guide.
Quick answers
What is a normal water flow rate for a UK home?
As a guide, a kitchen cold tap should manage roughly ten litres a minute, which is a one-litre jug in about six seconds. Companies must also keep a minimum pressure of about 0.7 bar at your boundary. If you measure well below that, ask your water company for a pressure test; most offer them free.
Why is my water pressure suddenly low?
Sudden usually means something changed: plumbing work that left the stopcock or an isolation valve half-shut, a burst main nearby, or a new leak on your own supply. Check the stopcock first, then the company incident map, then run the meter test with everything off to rule out a hidden leak.
Why is only my hot water pressure low?
Because the restriction sits in the hot side: limescale narrowing a combi boiler’s plate heat exchanger, a part-closed valve on the cylinder circuit, or the natural limits of a gravity-fed cylinder system. A plumber can diagnose the cylinder side, but any work inside a gas boiler’s casing needs a Gas Safe registered engineer.
Can my water company fix low pressure?
If the problem is on their side of the boundary, yes, and they are obliged to meet minimum pressure standards, with compensation schemes when they persistently fail. They will test free of charge in most areas. If their supply arrives healthy and dies inside your home, the fix, and the bill, is yours.
This guide is general information for UK homes, not advice about your specific property. Anything involving gas must be done by a Gas Safe registered engineer, and notifiable electrical work by a qualified electrician. If you smell gas, call the National Gas Emergency line on 0800 111 999. If you’re ever unsure, stop and get a professional in — that’s exactly what Tickover is for.
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