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Problem Guides

Low Water Pressure

Weak flow from taps, showers, or throughout the home

6 free DIY guides · 17 total

Low water pressure affects millions of UK homes and can have completely different causes depending on where the problem occurs. Weak flow at a single tap usually points to a blocked aerator or a partially-closed isolator valve; poor pressure throughout the whole house could be the mains supply, a failing PRV (pressure reducing valve), or an undersized internal pipework layout. Shower pressure problems have their own set of causes entirely. These guides help you identify the root cause — whether it's inside your property or on the supply side — and restore normal flow without unnecessary callouts.

Step 1 — What type of system do you have?

The diagnosis is different depending on your system — this helps us point you to the right guide.

Boiler Expansion Vessel — How to Check and Recharge
Expansion vessel has failed — pressure relief valve keeps discharging or pressure fluctuates wildly· 30 min–2 hrs
Boiler keeps losing pressure
Pressure drops repeatedly and needs regular topping up· 5–10 min
Boiler pressure keeps dropping after topping up
Pressure falls back below 1 bar repeatedly — there is an underlying fault, not just low pressure· 15 min
Boiler pressure keeps dropping — why and how to fix it
Boiler pressure gauge falls below 1 bar repeatedly — system losing pressure· 30 min–4 hrs
Filling loop is dripping or leaking
Water leaking from the flexible hose under the boiler· 5 min
How to Use a Boiler Filling LoopFree
Filling loop under the boiler to repressurise the heating system· 10–15 min
How to repressurise a boiler using the filling loopFree
Boiler pressure has dropped — step-by-step guide to topping up· 5–10 min
Low Water Pressure Throughout the Whole House
If every tap in the house has low pressure, the problem is likely with the mains supply or the main stopcock.· 30 min–3 hrs
Low flow rate from all taps and showers
Water comes out slowly from every outlet — not just one tap· 30 min–1 day
Low mains water pressure throughout the house
All taps have poor flow — mains supply pressure is low· 30 min–1 day
Low pressure from all tapsFree
Entire house has weak flow· 15 min–2 hrs
No or low water pressure upstairs onlyFree
Taps and shower upstairs have poor flow, downstairs fine· 20–40 min
Pressure reducing valve fault or failure
Pressure reducing valve (PRV) causing low pressure or failing to reduce pressure· 1–3 hrs (plumber)
Shower has low pressure — how to fix itFree
Weak shower flow even when all other taps are fine· 30 min
Water dripping from the pressure relief valve
Small pipe outside is dripping water· 5 min
Water pressure has dropped suddenlyFree
Good pressure yesterday, little flow today· 20–40 min
When do you need a water pressure booster pump?
Understanding when a pump will help and how to choose the right one· 2–4 hrs (installation)

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