What is normal water pressure in the UK?

Normal UK mains water pressure is between 1 and 4 bar (10 to 40 metres head). South West Water aims to provide a minimum of 1 bar at the boundary stopcock. Inside your home, pressure will be slightly lower due to friction and height. If your pressure is below 0.5 bar at the kitchen tap, it is worth investigating.

Why is my water pressure suddenly low?

A sudden drop usually points to a leak, a partially closed valve (often after recent plumbing work), or a mains supply issue in your area. Check your stopcock is fully open, ask neighbours if they are affected and check South West Water's website for known supply issues. If none of these apply, call a plumber to check for a hidden leak.

Can a plumber increase my water pressure?

Yes, depending on the cause. If the problem is a faulty PRV, corroded pipes or a partial blockage, fixing these will restore normal pressure. If your mains supply is genuinely low (under 1 bar at the boundary), a plumber can fit a mains booster pump (£250 to £500 fitted) to increase pressure throughout the house.

What is a pressure reducing valve (PRV)?

A PRV is a valve on your mains supply pipe that limits incoming water pressure to a safe level — typically 3 to 4 bar. This protects your plumbing, appliances and hot water cylinder from damage caused by excessively high mains pressure. If the PRV fails, it can either let too much pressure through or restrict flow too much.

Will a combi boiler work with low water pressure?

Most combi boilers need a minimum of 0.5 to 1 bar of mains pressure to fire. Below this, the boiler may not ignite or may cut out during use. If your mains pressure is consistently low, a system boiler with an unvented cylinder (which stores pre-pressurised hot water) may be a better option than a combi.

Is South West Water responsible for my low pressure?

South West Water is responsible for the mains pipe up to your property boundary. If the problem is on their side — a burst main, low pressure in the street — they will fix it at no cost. If the problem is on your supply pipe between the boundary and your house, it is your responsibility. Contact them on 0344 346 2020 to check.

How much does a mains booster pump cost?

A whole-house mains booster pump typically costs £250 to £500 fitted in the Exmouth area. This includes the pump, installation on the incoming mains pipe and a small expansion vessel. Running costs are minimal — a few pounds per year in electricity. The pump only runs when water is flowing.

Water Pressure Problems in Exmouth

Low water pressure can make showers miserable, boilers unreliable and taps frustratingly slow. Find out what causes poor pressure, how to diagnose the problem yourself and when to call a local Exmouth plumber.

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Common Causes of Low Water Pressure

Low pressure is a symptom, not a diagnosis. These are the most common underlying causes in Exmouth homes.

Hidden leak

A leak anywhere in your plumbing system reduces the pressure available at your taps. Underground supply pipe leaks are especially hard to spot — you may only notice a higher water bill or a damp patch in the garden. Even a small leak on an internal pipe behind a wall can cause a noticeable pressure drop.

Corroded or restricted pipes

Galvanised steel and older lead pipes corrode internally over time, narrowing the bore and restricting flow. A pipe that started at 15mm internal diameter may be down to 5mm after decades of scale and rust build-up. This is common in pre-1960s Exmouth properties.

Faulty pressure reducing valve (PRV)

Many Exmouth homes have a PRV on the mains supply pipe where it enters the property. This valve limits incoming pressure to protect your plumbing. If it fails or is set too low, it can throttle your supply. PRVs typically last 10 to 15 years before needing replacement.

Shared supply pipe

Some older Exmouth properties — particularly terraced houses and flats — share a mains supply pipe with neighbours. When multiple homes draw water simultaneously, pressure drops for everyone. The permanent fix is a dedicated supply pipe from the mains, which South West Water can arrange.

Partially closed stopcock or valve

The simplest cause and the easiest fix. If your stopcock is not fully open, it restricts flow to the whole house. This often happens after plumbing work when the stopcock is not turned back fully. Check that the valve is turned fully anti-clockwise.

Mains supply issue

Sometimes low pressure is not your problem at all — South West Water may have reduced mains pressure temporarily for maintenance or there may be a burst main in the area. Check with neighbours and contact South West Water on 0344 346 2020 to report or check for known issues.

How to Diagnose Low Water Pressure

Work through these checks before calling a plumber — you may be able to fix the problem yourself in minutes.

Check if the problem is isolated or whole-house

Run taps in different rooms. If only one tap has low pressure, the issue is local — a blocked aerator, partially closed isolation valve or a problem with that specific pipe run. If every tap is affected, the problem is upstream: your supply pipe, stopcock or mains supply.

Check your stopcock is fully open

Find your internal stopcock (usually under the kitchen sink) and turn it fully anti-clockwise. If it was partially closed, this alone may restore normal pressure. If the stopcock is seized, do not force it — a plumber can replace it for £100 to £250.

Clean your tap aerators

Unscrew the small mesh filter at the end of each affected tap. Soak it in white vinegar for 30 minutes to dissolve limescale, then rinse and refit. Exmouth has moderately hard water, so blocked aerators are a common cause of apparently low pressure at individual taps.

Check your water meter

Turn off all taps and appliances that use water. Watch the meter dial for 15 minutes. If it moves, you have a leak somewhere. Even a slow leak can reduce overall system pressure. A leak detection specialist can pinpoint the location without digging.

Measure your pressure

Screw a pressure gauge onto an outside tap or washing machine valve. Normal UK mains pressure is 1 to 4 bar. Below 1 bar is considered low. If your reading is under 1 bar at the mains entry point, the problem is likely the supply pipe or the mains itself.

Call a plumber if the problem persists

If you have checked the obvious causes and pressure is still low, a plumber can test your PRV, inspect your supply pipe and check for hidden leaks. Some issues — like a corroded supply pipe or a shared main — need professional assessment.

Suspect a leak? Read our guide on 5 signs you have a hidden water leak or find a leak detection specialist in Exmouth.

Solutions & Typical Costs

What it costs to fix depends entirely on the cause. Here is a breakdown from free DIY checks to major pipework. For a full breakdown of plumbing rates, see our plumber costs guide.

Quick Fixes

Open the stopcock fullyFree
Clean blocked tap aeratorsFree (DIY)
Open partially closed isolation valvesFree

Moderate Repairs

Replace a faulty PRV£150–£300
Replace a seized stopcock£100–£250
Repair a leaking pipe joint£80–£200
Fit a mains booster pump£250–£500

Major Work

Replace underground supply pipe£500–£1,500
Repipe corroded internal pipework£1,500–£4,500
New dedicated mains connection£800–£2,000+
Install an unvented hot water system£1,500–£3,000

Prices are estimates for 2026. Always get a written quote before work begins.

Water Pressure FAQs

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Think you might have a leak? See our leak detection page or read about hidden leak warning signs. Need pipe repair or replacement? Not sure what's wrong? Try our diagnosis tool.