Water Pressure Suddenly Dropped? Causes & Solutions

January 2026 Mend Your Home Plumbing

Has your water pressure suddenly dropped? Weak showers, slow-filling taps, and appliances that won't work properly are all signs of a water pressure problem. This guide helps you identify the cause and find a solution.

First: Is It Your Property or the Mains?

Before investigating further, determine if the problem is just your property or a wider issue:

Check These First

Ask neighbours - Are they affected too?
Check outside tap - Is pressure low there?
Contact water company - Any planned works?
Check all taps - Is it whole house or just one?

What It Tells You

Neighbours affected = Mains supply issue
Just your home = Internal problem
Just one tap/area = Localized blockage
Just hot water = Boiler/cylinder issue

Water Company Issues: If it's a mains supply problem, contact your water company (Southern Water in most of West Sussex). They're responsible for the supply up to your boundary.

Common Causes of Low Water Pressure

DIY Checks

Stopcock Partially Closed

Your internal stopcock (usually under kitchen sink) may have been accidentally knocked. Turn it fully anti-clockwise to ensure it's completely open.

Blocked Tap Aerators

The mesh filters in tap spouts can clog with debris. Unscrew the aerator at the tap end and clean or replace it.

Showerhead Limescale

If just the shower is weak, limescale may be blocking the showerhead. Soak in descaler or replace.

Needs a Plumber

Leaking Pipes

A leak in your supply pipe (often underground) can cause pressure loss. Signs include damp patches, increased water bills, or hissing sounds.

Corroded/Blocked Pipes

Older properties (especially with lead or galvanized steel pipes) can have internal buildup restricting flow. May need pipe replacement.

Faulty Pressure Reducing Valve

If your property has a PRV (common in high-pressure areas), it may have failed or need adjusting.

Shared Supply Issues

Some properties share a supply pipe. When neighbours use water, pressure drops. Solution may be a dedicated supply or pump.

Need Help Finding the Cause?

We can diagnose and fix water pressure problems across West Sussex & Surrey

Call: 07960 066300 Request Callback

Low Pressure vs Low Flow Rate

These are different issues with different solutions:

Low Pressure

Water comes out weakly even when only one tap is on.

Caused by: Mains supply, pipe issues, blockages, leaks

Low Flow Rate

Pressure drops when multiple outlets are used.

Caused by: Pipe diameter too small, shared supply, combi boiler limitations

Solutions for Low Water Pressure

Options Depending on the Cause:

Water Pressure Booster Pump

If mains pressure is consistently low, a booster pump can increase pressure throughout your home.

Cost: £300-£1,000 on average for an average 3 bed home installed, depending on type

Supply Pipe Upgrade

Replacing a narrow or corroded supply pipe with modern 25mm+ MDPE pipe improves flow significantly.

Cost: £800-£3,250 on average for an average 3 bed home depending on length and complexity

Leak Detection & Repair

If a leak is causing pressure loss, we can locate and repair it, often without major excavation.

Cost: Varies depending on leak location and accessibility

Pumped Shower

If just the shower is weak, a pumped shower unit can boost pressure without affecting the whole house.

Cost: £200-£500 on average for an average 3 bed home installed

What Pressure Should I Have?

Water companies are required to provide a minimum of 1 bar of pressure at the boundary of your property. However:

1 bar = Minimum legal requirement (may feel weak)
1.5-2 bar = Good pressure for most homes
2-3 bar = Strong pressure
Over 3 bar = May need pressure reducing valve

You can measure your pressure with a simple gauge that attaches to an outside tap. We can also test this during a visit.

Frequently Asked Questions

Why is my pressure fine in the morning but weak in the evening? ▼

This indicates your supply can't keep up with demand. In the evening, when more people are using water (showers, cooking, etc.), mains pressure drops. This is common with shared supplies or undersized pipes. A booster pump or pipe upgrade can help.

My hot water pressure is fine but cold is weak - why? ▼

This suggests a blockage or restriction on the cold water supply side, possibly at the stopcock, a valve, or in the cold water pipes. The hot water (if from a combi boiler or unvented cylinder) may have better flow due to different pipework.

Can a combi boiler cause low pressure? ▼

Combi boilers are limited by their flow rate (typically 9-12 litres per minute). If you're running multiple hot water outlets, pressure will drop. This is a flow rate limitation, not pressure. Larger combi boilers or a system boiler with unvented cylinder can provide better flow for larger households.

Will a water softener affect my pressure? ▼

A properly installed water softener should have minimal impact on pressure. However, if the softener is undersized, blocked with sediment, or incorrectly installed, it can restrict flow. We can check and resolve softener-related pressure issues.

Fix Your Water Pressure Today

Expert plumbers serving Crawley, Horsham, Redhill, Reigate and all West Sussex & Surrey

Call: 07960 066300