Low Water Pressure Throughout the House
Reviewed by the Devon Leak Detection team. Last updated June 2026
The short answer
Low pressure across the whole house usually points to one shared cause rather than a single tap. The most common culprits are a partially closed stop tap, a leak or restriction on the underground supply pipe, a temporary mains issue, or scaled, narrowed pipework. Check your stop tap first, then ask neighbours if they are affected too.
When a single tap runs weakly, the problem is usually local to that fitting. When every tap and shower in the house has dropped off, the cause sits further back, somewhere on the route that brings water from the public main into your home. The good news is that whole-house low pressure narrows the list of suspects considerably, and several of the checks you can do yourself in a few minutes. This guide walks through the likely causes in the order worth investigating, and explains when a leak on your supply pipe is the real reason behind the weak flow.
First, work out how widespread it is
Before you start hunting, gather a little information. Has the pressure dropped gradually over months, or did it fall away suddenly? A slow decline often points to scale building up inside older pipework or a valve creeping shut. A sudden drop is more likely to be a fresh leak, a closed valve after recent work, or something happening out on the network.
It also helps to know whether your neighbours are affected. If the houses around you have weak pressure at the same time, the issue is almost certainly on the public side rather than yours. If you are the only home affected, the cause is very likely somewhere on your own pipework or fittings.
A partially closed stop tap
This is the most common cause, and the easiest to fix, so it is always worth ruling out first. Your internal stop tap (also called a stopcock) controls all the mains water entering the property. It is usually found under the kitchen sink, though in some homes it sits in a utility room, a downstairs cupboard, or near the front door.
If anyone has turned the water off recently, for a repair, a new appliance, or a frozen-pipe scare, the tap may have been reopened only part of the way. A stop tap that is half closed will throttle the flow to the whole house. Turn it gently anticlockwise until it stops, then back it off a quarter turn so it does not seize. Many homes also have an external stop tap near the boundary, often under a small cover in the path or pavement, which can have the same effect if it is not fully open.
A temporary problem on the mains
Sometimes the weak flow has nothing to do with your home at all. Planned works, a burst main nearby, or simple peak demand in the morning and evening can all reduce pressure across a street temporarily. Your water company is generally expected to maintain a minimum level of pressure in the pipe that serves your boundary, and there are industry standards covering this, so a persistent shortfall is worth raising with them.
If you live in Devon, your supplier is typically South West Water. Their website usually lists current works and known issues in your postcode, and you can report a pressure problem directly. If neighbours are affected too, this is the first place to look before you spend money investigating your own pipes.
A leak or restriction on the supply pipe
The supply pipe is the underground run that carries water from the boundary of your property into the house, usually beneath the garden, drive or path. As a homeowner you are generally responsible for this section, and it is a frequent reason for whole-house pressure loss. A leak here lets water escape before it reaches your taps, so the flow that does arrive is noticeably weaker. A partial restriction (a crushed section, a kink, or a build-up of debris and scale narrowing the bore) has the same effect without any water surfacing.
Supply-pipe leaks are easy to miss because the pipe is buried. Water can track along the pipe, soak away into the ground, or run into a nearby drain without ever showing on the surface. That is exactly why low pressure with no obvious puddle is such a common sign of a hidden leak rather than a harmless quirk.
Signs a supply-pipe leak might be to blame:
- Pressure has fallen across every tap, not just one
- Your water meter keeps ticking over when all taps are off
- A patch of lawn, drive or path stays damp or greener than the rest
- An unexplained rise in your metered water bill
- Neighbours are not affected, so the cause is on your side
A shared supply
In some older terraces and rural properties, a single pipe feeds more than one home before splitting off. Where a supply is shared like this, the pressure you get can dip when a neighbour draws a lot of water at the same time as you, which is why mornings and evenings often feel weakest. If your pressure is fine at quiet times but drops away at busy ones, a shared supply may be part of the picture. It can also mean a leak on the shared run affects several homes at once, so it is worth comparing notes with the properties that share the pipe.
Scale and ageing pipework
In harder-water areas, limescale gradually coats the inside of pipes and fittings, narrowing the channel water flows through. Older galvanised steel pipework can also corrode and fur up internally over the years. Either way the effect builds slowly, so a steady decline in pressure over a long period, rather than a sudden change, can point this way. Scaled-up isolation valves, filters and the small mesh aerators on tap spouts can all add to the restriction. If clearing or replacing a tap aerator improves that one tap but the rest of the house stays weak, the narrowing is likely further upstream.
Simple checks you can do yourself
A few quick steps will tell you a great deal before you call anyone out. Confirm both your internal and external stop taps are fully open. Ask a couple of neighbours whether their pressure has dropped too. Then try a simple meter test: turn off every tap and water-using appliance in the house, find your water meter, and watch the dial. If it keeps moving with everything switched off, water is escaping somewhere on your side, and a supply-pipe leak becomes the leading suspect.
If the stop taps are open, the neighbours are fine, and the meter is creeping, it is sensible to have the supply pipe checked properly. Pinpointing a buried leak without digging up the whole garden is exactly what professional leak detection is for. You can read more about how we trace mains-side losses on our mains water leak detection page, see the areas we cover across Devon, or browse more guides in our articles library.
Who pays for the repair?
As a rule, the water company looks after the public main and the section up to your boundary, while the supply pipe from the boundary into your home is the homeowner’s responsibility. That said, many suppliers offer help with the cost of finding and fixing an external supply-pipe leak, and metered customers may be able to claim an allowance for water lost while the leak was running. The exact support varies, so it is worth checking with South West Water for the schemes and figures that apply to your property before arranging a repair.
Frequently Asked Questions
When every tap is weak, the cause sits on the shared route into the home rather than one fitting. The usual suspects are a partially closed stop tap, a leak or restriction on the underground supply pipe, a temporary mains issue, scaled pipework, or a shared supply under heavy demand. Start by checking the stop tap.
Turn off every tap and appliance, then watch your water meter. If the dial keeps moving with nothing in use, water is escaping somewhere on your side and a supply-pipe leak is the likely cause. A persistently damp patch of ground or an unexplained rise in a metered bill are further clues worth taking seriously.
Generally the water company maintains the public main up to your boundary, and the supply pipe from the boundary into your home is the homeowner’s responsibility. Many suppliers offer help with the cost of an external leak, so check with South West Water for the support and any allowance that applies to your property.
Yes, it is one of the quickest ways to narrow things down. If neighbouring homes have lost pressure at the same time, the problem is almost certainly on the public network and worth reporting to your supplier. If you are the only one affected, the cause is far more likely to be on your own pipework or fittings.
In most cases, yes. Specialist leak detection uses non-invasive methods such as acoustic listening, tracer gas and thermal techniques to pinpoint a hidden leak before any excavation. That means the repair can be targeted to a small area rather than lifting an entire driveway or lawn.
Lost pressure and not sure why?
If the stop taps are open and the meter is still moving, we can trace a hidden supply-pipe leak without tearing up your garden.