Fix low water pressure in a tap
Save £60–100 in 30 mins — no plumber needed
Low water pressure in one tap is almost always a blocked aerator or a partially closed valve — both take minutes to fix. This guide walks you through the diagnosis in order so you fix the right thing first time.
Last updated: March 2025
Only basic tools needed — most homes already have them.
Before you start
First establish whether it is one tap, one room, or the whole house. That tells you immediately where to look. The fix for a single-tap problem (blocked aerator) is completely different from a whole-house problem (stop valve or mains).
In hard water areas — most of England — limescale is the most common cause. The water supplier's website will tell you your water hardness level if you are unsure.
You do not need to turn off the water to remove and descale an aerator on a tap with an isolation valve.
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Tools & materials
- ✓Flat-head screwdriver— to check isolation valve positions and remove some aerators
- ✓Small bowl— to soak the aerator in vinegar
- !White vinegar— essential for descaling — any supermarket, under £2
- !Replacement aerator (if damaged)— match the thread size — take the old one to the hardware shop
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Establish whether the problem is one tap or all taps
Turn on every cold tap in the house — kitchen, bathroom, outside tap if you have one. Note which ones are affected. If pressure is poor at just one tap, the problem is local to that fitting (blocked aerator, partially closed valve). If all cold taps are equally low, the problem is the mains supply or the main stop valve. If hot taps are the problem but cold taps are fine, the hot water cylinder or boiler pressure is the issue — see our repressurise a boiler guide. Why: diagnosing which category you are in determines what to do next. Cleaning an aerator will not fix a mains pressure problem and vice versa. This step takes two minutes and narrows the cause immediately.
Most people get this done in under 5 minutes.
Where beginners go wrong
Assuming one low-pressure tap means a whole-house problem. Check every tap first. A blocked aerator on one fitting looks like poor pressure, but the rest of the house is fine. Two minutes of testing tells you which category you are in.
Putting the aerator back without rinsing properly. Vinegar loosens limescale but does not always flush it clear. Rinse the aerator under a running tap for 30 seconds to clear all loosened debris before refitting.
Not checking the stop valve position. A stop valve 80% open feels fully open when you turn the handle — but it is cutting pressure to the whole house. Make sure it is turned fully anticlockwise and cannot rotate any further.
Trying to fix mains pressure yourself. If the water company's supply is low, there is nothing on your property that will fix it. The PRV (pressure reducing valve) on the mains inlet adjusts the incoming pressure, but it should only be touched by a plumber.
Stop and call a plumber if...
You suspect the PRV (pressure reducing valve) on the mains inlet is faulty — this is a specialist job
There is a visible leak on the mains pipe coming into the property — loss of pressure plus a leak means the pipe itself is the problem
Pressure has dropped suddenly on all taps at once — this often indicates a burst pipe or major leak elsewhere in the system
Cost breakdown
Recommended starter kit
Five tools that cover most home repairs.
- →Adjustable spannerAmazon·Screwfix
- →Screwdriver setAmazon·Screwfix
- →PTFE tapeAmazon·Screwfix
- →Spirit levelAmazon·Screwfix
- →Tape measureAmazon·Screwfix
Want everything in one go? Get it on Amazon
What you just learned
You can diagnose a water pressure problem at home — distinguishing between a local issue (aerator, valve) and a mains issue — and fix the most common causes yourself. The diagnostic approach here transfers to tracing airlocks in pipes, understanding why one radiator is cold, and identifying where in the system any water problem originates.
This unlocks:
⚠️ Watch out if you rent
If low pressure is a whole-house issue, it is the landlord's responsibility to investigate and fix. Report it in writing. For single-tap issues, cleaning an aerator is a reasonable tenant repair.