Is there anything more annoying than low water pressure? Every time you take a shower or wash the dishes, you’re suddenly dealing with a weak trickle. Low water pressure disrupts your everyday routine, but it’s more than a mere annoyance. It can signal that there’s something going wrong somewhere in your house.
Pinpointing the source of the problem can prevent the worst damage. That’s especially true if the water pressure is weak due to a leaking pipe. Never ignore low water pressure. Understanding why it happens and what could be behind it is crucial to protecting your home and fixing the issue.
What Is Considered Low Water Pressure in a House?
In most UK homes, normal water pressure sits between 1 and 3 bar. Anything below 1 bar is generally considered low. It’s when problems first become noticeable. You might find taps run slowly, showers taper off, or appliances like washing machines take forever to refill.
But, low water pressure doesn’t affect every outlet equally. You might notice one tap or shower has weak pressure. If that’s the case, the problem is usually local, e.g., a blocked fixture or worn valve. But if the water pressure is low everywhere, it’s probably down to the main supply internal pipework, or a pressure control issue.
There’s also cold and hot water pressure to think about. Low hot water pressure is usually due to a boiler, cylinder, or heating system issue, whereas if both hot and cold are affected, it’s likely to be a wider problem.
First Things First: Check Your Main Water Valve
The first thing you want to check is the main water valve. If the main water valve is closed or faulty, it can cause a systemic reduction in pressure.
Here’s what to do:
- Locate the stopcock – usually under the kitchen sink, near the front of the house, or inside an external water meter box.
- Check the direction – the valve should turn anticlockwise to fully open.
- Open it fully – turn slowly until it stops; don’t force it if it feels stiff.
- Test the pressure – turn on a cold tap and see if the flow improves immediately.
- Watch for leaks – if the valve drips or won’t turn smoothly, it may need replacing.
Don’t start adjusting things yourself if there’s a serious problem. The only thing you’ll want to do if there is a leak is to turn the valve off. You should then call an emergency plumber.
Old or Corroded Pipes Causing Low Water Pressure
Old or corroded pipes can cause systemic or local drops in water pressure. Pipe corrosion, mineral buildup, or leaks restrict water flow, particularly near outlets like taps and showers.
This type of problem rarely occurs suddenly. The water pressure will gradually drop over time, worsening over months or years. You might also notice discoloured water, unusual tastes, or uneven pressure between different parts of the house.
Blocked Taps, Showerheads, and Fixtures Reducing Water Flow
If the problem is restricted to a single tap, shower, or fixture, it’s not a systemic problem. The issue is likely a blockage in the pipe leading to the fixture or the fixture itself.
Sediment, lime, and debris buildup in aerators and nozzles are all common. This problem is common in areas with hard water. Scraping away the limescale or replacing the fixture should restore flow without any issues.
Could a Faulty Pressure Regulator Be the Problem?
Most homes have a pressure-reducing valve (PRV). It protects pipework and appliances from excessive mains pressure. However, if the valve starts to fail, it can restrict flow too much, leading to low water pressure throughout the house.
Signs of a faulty pressure regulator include:
- Sudden drops in pressure
- Inconsistent flow
- Pressure that fluctuates during the day
Unlike blocked fixtures, these issues usually affect both hot and cold water across multiple outlets. It’s best not to fix the issue alone. If you suspect a faulty pressure regulator, a plumber can test the system and replace the valve if necessary.
Shared Water Supply and Peak Usage Times Explained
Notice a sudden drop in pressure at certain times of day? The problem might be outside your home.
Often, a property’s water supply is shared or exists at the end of a mains line. This means when usage peaks, e.g., in early mornings or evenings, water pressure can drop.
The most obvious sign is the timing pattern. When neighbours are showering, using washing machines, or watering gardens, pressure falls. Outside these hours, pressure usually returns to normal. Plumbers can help by installing pressure-boosting solutions.
Leaking Pipes and Hidden Water Damage That Lower Pressure
Leaks aren’t always a sudden burst pipe or water running down the walls. Small, hidden leaks can hide behind walls or under floors and the only tell-tale sign is a drop in water pressure.
Look for unexplained damp patches, mould, musty smells, or a higher-than-usual water bill. In fact, low water pressure might be the only obvious symptom.
Low Water Pressure from a Boiler, Well Pump, or Private Water System
If low hot water pressure is the problem, it’s almost always a boiler or hot water system. Combination boilers can struggle if internal components fail, while older systems with gravity-fed cylinders deliver lower pressure.
You’ll need a plumber to inspect the entire system to determine the issue. Worn pumps, pressure tank issues, or electrical faults can all lead to weak or inconsistent hot water flow.
Getting your boiler service regularly can help spot issues before they become major problems. Find out how often you should service your boiler.
How to Diagnose and Fix Common Low Water Pressure Problems
Suspect a problem with low water pressure? Here’s what you should do:
- Check whether the issue is local or whole-house. Low pressure at one tap usually points to a blocked fixture. Low pressure everywhere suggests a supply or system issue.
- Compare hot and cold water pressure. Weak hot water may indicate a boiler or cylinder problem, while both being low points to the mains or pipework.
- Test pressure at different times of day. Pressure that drops in the morning or evening may be caused by shared supply or peak demand.
- Inspect visible pipework for leaks or corrosion. Look for damp patches, staining, or drips around exposed pipes and valves.
- Clean or replace blocked fixtures. Remove limescale from showerheads and tap aerators to rule out simple flow restrictions.
- Check the main stopcock and pressure regulator. Ensure valves are fully open and functioning correctly.
When It’s Time to Call a Professional Plumber
Unless the cause of the low water pressure is a simple fix like a blocked tap, it’s best to call in a professional. Trying to fix the underlying problem yourself can lead to further issues.
Premium Heating, Plumbing & Cooling can inspect your water system, finding the cause of the low water pressure. We’ll advise on the best solution, getting your pressure up in no time. Contact us today if you’re dealing with water pressure that’s weak.