Low Water Pressure in the House? Causes and How to Fix It

Weak showers, taps that trickle, and appliances that take an age to fill are all signs of low water pressure. Sometimes the fix is quick and free; other times it points to a fault worth investigating. This guide explains the common causes of low water pressure in the house and how to fix them.

First: is it one tap or the whole house?

Start by checking whether the problem affects a single tap or every outlet. One tap or shower with low pressure usually means a blocked aerator or a faulty fitting. The whole house points to something affecting your main supply — the stopcock, a leak, or your water company’s supply.

Note: this guide is about your mains water pressure. If it’s your boiler’s pressure gauge reading low, that’s a separate system — see our guide on boiler pressure.

Common causes of low water pressure

The stopcock isn’t fully open: the most common and easily fixed cause. If it’s been turned recently (for example after plumbing work), it may not be fully open.
Blocked aerators or showerheads: limescale builds up in the small filters on taps and showerheads, restricting flow.
Your water supplier’s pressure: supply can drop at peak times. Water companies must provide a minimum pressure (around 1 bar) at your boundary.
A hidden leak: a leak somewhere in your pipework reduces pressure and often shows up as a rising water bill.
A faulty pressure-reducing valve: if fitted, this valve can fail and choke your flow.
Old or corroded pipework: narrowed or scaled-up pipes restrict flow, common in older properties.

How to improve water pressure yourself

Check the stopcock is fully open. Find it (usually under the kitchen sink) and turn it anti-clockwise as far as it goes.
Clean the aerators. Unscrew the tip of the tap or the showerhead, soak the filter in white vinegar to dissolve limescale, rinse and refit.
Ask your neighbours. If they have the same problem, it’s a supply issue for your water company to resolve.
Check for leaks. A sudden drop in pressure with no obvious cause can indicate a leak that needs finding quickly.

When to call a plumber

If the stopcock is open, the aerators are clean, and your neighbours’ supply is fine, the cause is likely inside your system — a leak, a faulty pressure-reducing valve, or corroded pipework. These need a professional to diagnose. A plumber can carry out a pressure test, trace any leaks, and recommend the right fix, which may include a pump or an upgrade to your pipework.

Frequently asked questions

Why has my water pressure suddenly dropped?

A sudden drop often means the stopcock has been knocked, there’s a leak, or your water company is carrying out work. Check with neighbours first, then look for signs of a leak.

What is normal water pressure for a house?

Most UK homes sit between 1 and 3 bar. Your water company must provide a minimum of around 1 bar at the boundary, but internal factors can reduce it below that at the tap.

Can low water pressure be fixed?

Usually, yes. Simple causes like a part-closed stopcock or a limescaled aerator are quick fixes. Leaks, valve faults or old pipework need a plumber, and a pump can boost pressure where the mains supply is genuinely low.

Need a plumber in West London?

If low water pressure is affecting your home and the simple checks haven’t solved it, we can find the cause. Our team provides fast, reliable plumbing services across West London, with no call-out surprises and honest, up-front pricing.

Tel: 020 3561 4415