Low Water Pressure: Causes, Fixes, and When to Call a Plumber

What Causes Low Water Pressure?

Low water pressure is frustrating and can affect everything from shower performance to boiler function. The causes vary significantly depending on your property's plumbing setup and what's changed recently.

Check Whether It's Localised or Whole-Property

First, determine whether the problem affects just one outlet (a single tap or shower) or the whole property. A localised problem points to a blocked aerator, faulty fixture, or closed isolation valve. A whole-property problem suggests a wider cause.

Common Causes

Low mains pressure from the supplier: Your water company delivers water at a certain pressure to your property boundary. If this is low, all outlets in the property will be affected. You can check by disconnecting the supply at the meter — if the pressure there is low, it's a supplier issue. Contact your water company.

Partially closed stopcock: The main stopcock (under the kitchen sink or where the supply enters) may have been partially closed during previous work. Check it's fully open.

Corroded or scaled pipework: Old lead, iron, or even copper pipes can scale up significantly over decades, restricting flow. This is a particular issue in hard water areas like Surrey.

Faulty pressure reducing valve (PRV): Many properties have a PRV fitted to reduce mains pressure. If this fails, pressure can drop dramatically.

Leaks: A significant leak in buried pipework can cause whole-property pressure loss. Signs include damp patches, unusually high water bills, or water pooling in the garden.

Fixes

When to Call a Plumber

If you cannot identify the cause, if pipework appears corroded, or if you suspect a leak, call a plumber promptly. Halo Heating's plumbing team covers Surrey. Call 01483 676108.