The short answer
If your water pressure is suddenly low, the cause is usually one of four things: work or a burst on the water company's main, a stopcock that is partly closed, a leak on your own supply pipe, or a failing valve inside your home. Checking whether your neighbours are affected is the quickest way to tell if the problem is yours or the water company's.
Quick checks to find the cause
- Ask a neighbour. If they have low pressure too, the problem is likely on the water company's network. Check your supplier's website for incidents.
- Check every tap. If only one tap or shower is weak, the problem is local to that outlet, often limescale or a blocked aerator.
- Check the stopcock. Make sure it is fully open. It may have been partly closed by a plumber or during other work.
- Check for leaks. Look for damp patches, a running toilet or a water meter that moves with every tap off.
- Think about recent work. New bathrooms or valves fitted recently can restrict flow if set up badly.
Common causes of low water pressure
| Symptom | Likely cause |
|---|---|
| Whole street affected | Water company works or a burst main |
| Whole house, sudden | Part-closed stopcock, leak on supply pipe or failed pressure-reducing valve |
| Whole house, slow over years | Old iron or lead pipes furred inside |
| One tap or shower | Limescale, blocked aerator or faulty valve |
| Drops when other taps run | Supply pipe too small for the number of bathrooms |
When to call a plumber
Call a plumber if pressure is low across the whole house and neighbours are fine, if you suspect a leak, or if your stopcock is stiff or broken. A plumber can measure pressure and flow, find the restriction and explain the best fix, such as replacing a valve, clearing a blockage or upgrading the supply.
What does it cost?
Checkatrade's 2026 figures put the average UK plumber at about £50 an hour, and London rates are higher. Many pressure problems are diagnosed and fixed within one visit. We give a written price before any work starts.
Related service: low water pressure repairs.
A few common questions
Why has my water pressure suddenly dropped?expand_more
A sudden drop is usually caused by water company works or a burst main, a stopcock that is partly closed, a leak on your supply pipe or a failed valve. Ask a neighbour first: if they are affected too, the problem is likely on the water company's side.
How do I check if low pressure is my problem or the water company's?expand_more
Ask neighbours whether their pressure has dropped and check your water supplier's website for incidents. If only your home is affected, check your stopcock is fully open and look for leaks. If the cause is still unclear, a plumber can measure pressure and flow at your stopcock.
Can a leak cause low water pressure?expand_more
Yes. A leak on the supply pipe between the boundary and your home lets water escape before it reaches your taps, lowering pressure. Signs include damp patches outside, a wet floor near the stopcock or a water meter that keeps moving when every tap is off.
Why is only my shower pressure low?expand_more
If only the shower is weak, the cause is usually limescale in the shower head, a blocked filter or a faulty mixer valve. Cleaning or replacing the head often helps. If the problem remains, a plumber can check the valve and the pipework feeding it.
How much does it cost to fix low water pressure?expand_more
Checkatrade's 2026 figures put the average UK plumber at about £50 an hour, and London rates are higher. Simple fixes like opening a valve or clearing a blockage are quick. Replacing a supply pipe costs more. Ask for a written price once the cause is found.