Low Water Pressure? Here's What Causes It and How to Fix It
Diagnosing the Problem: 5 Questions to Ask
Before you call a plumber (or panic), answer these five questions. They narrow down the cause quickly and may save you a callout fee.
Is it one tap or the whole house?
This is the first question to answer. If only one tap or shower has low pressure, the problem is local to that fitting — usually a blocked aerator, a kinked flexible hose or a partially closed isolation valve. If every outlet is weak, the issue is further upstream.
Is it hot water, cold water or both?
Low pressure on cold taps only usually points to a supply or pipework issue. Low pressure on hot water only may mean a problem with your boiler, hot water cylinder or a restriction on the hot pipe run. If both are weak, the mains supply or your main stopcock is the likely culprit.
Did it happen suddenly or gradually?
A sudden drop often means a leak, a valve that has been closed during recent work or a mains supply issue in your area. Gradual decline over months or years typically points to pipe corrosion narrowing the bore, or limescale build-up in a hard water area.
Are your neighbours affected?
If neighbours have low pressure too, the problem is on South West Water's side — a burst main, planned maintenance or a supply capacity issue. Contact them on 0344 346 2020. If only your property is affected, the issue is your supply pipe, internal plumbing or both.
Does pressure drop when other taps are running?
If pressure is fine when one tap is running but drops noticeably when a second or third is opened, your supply pipe may be undersized or partially blocked. This is common in older properties with original 15mm lead or galvanised steel supply pipes that should have been upgraded to 25mm or 32mm.
Not sure what you're dealing with? Try our interactive diagnosis tool for a guided walkthrough.
Fixes You Can Do Yourself
Before calling a plumber, try these — they are free, take minutes and solve the problem more often than you might expect.
Clean your tap aerators
Easy — 5 minutes per tap
The aerator is the small screw-on mesh filter at the end of your tap spout. It mixes air into the water stream for a smoother flow, but it traps limescale, grit and debris over time. Unscrew it by hand or with pliers (wrap with a cloth to avoid scratching), soak in white vinegar for 30 minutes, scrub with an old toothbrush and refit. This alone restores pressure in a surprising number of cases.
Check your stopcock is fully open
Easy — 1 minute
Your internal stopcock is usually under the kitchen sink. Turn it fully anti-clockwise (as far as it will go). It is common for stopcocks to be left partially closed after plumbing work. Even a quarter-turn from fully open can restrict flow noticeably. If it is seized, do not force it — a plumber can replace it.
Check isolation valves
Easy — 1 minute per valve
Each tap and appliance usually has its own isolation valve nearby (a small valve with a flat-head screw slot). The slot should run parallel with the pipe for fully open. If the slot sits across the pipe, it is closed or partially closed. Turn it with a flat-head screwdriver.
Clean or replace your showerhead
Easy — 10 minutes (plus soaking time)
Showerheads clog with limescale, especially in Exmouth's moderately hard water. Remove the head and soak it overnight in white vinegar or a limescale remover. If the holes are still blocked, replace the head — a decent replacement costs £10 to £30 and makes a noticeable difference.
When You Need a Plumber: Solutions & Costs
If the DIY checks did not solve it, here is what a plumber can do and what it typically costs in the Exmouth area. For a full breakdown of plumbing rates, see our plumber costs guide.
| Solution | Cost |
|---|---|
| Replace a faulty pressure reducing valve (PRV) | £150–£300 |
| Replace a seized stopcock | £100–£250 |
| Fit a mains water booster pump | £250–£500 |
| Replace undersized supply pipe (15mm to 25mm) | £500–£1,500 |
| Replace underground supply pipe | £500–£1,500 |
| New dedicated mains connection | £800–£2,000+ |
| Repipe corroded internal pipework | £1,500–£4,500 |
| Install an unvented hot water cylinder | £1,500–£3,000 |
Prices are estimates for 2026. Always get a written quote before work begins.
Water Pressure Myths
There is a lot of bad advice about water pressure online. Here are four common myths and the reality.
Myth: A bigger boiler will fix low water pressure
Reality: Your boiler has nothing to do with mains cold water pressure. If hot water pressure specifically is the problem, it may be a boiler flow rate issue (combi boilers) or a cylinder/system issue — not the pressure from the mains.
Myth: South West Water must give me high pressure
Reality: Water companies are only required to provide a minimum of 1 bar at the boundary stopcock (the one in the pavement). Many Exmouth streets get 2 to 4 bar, but there is no guarantee of high pressure. If you need more, a booster pump is the solution.
Myth: A power shower will fix low pressure
Reality: A power shower has a built-in pump — but it only works with a gravity-fed (vented) hot water system. If you have a combi boiler or unvented cylinder (mains pressure), a power shower will not help and may not even be compatible. A mains booster pump is the correct solution for mains-pressure systems.
Myth: Low pressure means there is definitely a leak
Reality: A leak is one possible cause, but there are many others — corroded pipes, a partially closed valve, a faulty PRV or an undersized supply pipe. Always check the simple causes first before assuming the worst.
Water Pressure FAQs
Still Struggling with Low Pressure?
If the DIY fixes did not help, a local plumber can diagnose the cause and recommend the right solution. Browse our directory to find someone nearby.
Find Local PlumbersFor local service page and costs, see our water pressure problems page. Think you might have a leak? Read about hidden leak warning signs or find a leak detection specialist.