Water inside the water meter box is usually rain or groundwater and does no harm. It points to a leak only if the box refills in dry weather or the flow indicator turns with everything off. South West Water owns the meter and the pipe up to the boundary; the supply pipe from there is yours.
You lifted the lid on the meter box to take a reading and found the meter sitting in a puddle, or under water altogether. The first thought is a burst pipe and a bill to match. Take a breath. In Cornwall, where the ground stays wet from October to April, most of the water we find in meter boxes got there from above or from the sides, not out of the pipe. This guide covers telling the difference, working out which side of the meter the problem sits on, and who has to put it right. If the checks below point to a leak on your side, our water leak detection service picks it up from there.
Where the water in the box comes from
Four sources account for almost every wet meter box. Three of them cost you nothing.
- Rain and surface water. A boundary box is a plastic chamber in the ground with a lid that was never designed to be watertight. A heavy downpour, a lawn that slopes towards the box, or a blocked gully beside it will fill it. The water tends to be a little muddy, with leaves or grit in the bottom.
- Groundwater. When the water table rises in a wet winter, water seeps in through the base and around the pipe entries. It is usually clear, it rises and falls with the weather, and the box can stay damp for weeks after the last rain.
- Condensation. Cold mains water chills the meter casing and warm damp air condenses on it. You get droplets on the dial, never a pool.
- A leak. A weeping coupling on the meter itself, a split in the communication pipe on the road side, or a failed joint on your supply pipe close to the box. This is the one that keeps the box full when nothing else explains it.
The five-minute check
You need a torch, a sponge or jug, and something to write on. Work through the steps in order.
- Bail the box out. Sponge or scoop the water out until you can see the meter face and the fittings on both sides of it. If the box refills while you watch, you are looking at a live leak and can jump to the stop tap step.
- Turn everything off indoors. Every tap, the washing machine and the dishwasher. Give the toilet cisterns a few minutes to finish refilling, and take the hose off the outside tap.
- Watch the flow indicator. Most meters carry a small wheel, star or triangle on the face that turns whenever water passes through, even a trickle. With the house off it should be completely still. If it creeps round, water is going somewhere.
- Feel the fittings. Run a dry tissue around the joints on each side of the meter. A wet joint on the road side of the meter belongs to South West Water. A wet joint on the house side is yours.
- Close the internal stop tap and look again. If the indicator stops, the leak is inside your home. If it keeps turning with the stop tap closed, the leak is on the buried supply pipe between the box and the house, or on the meter fittings themselves.
If nothing moves and no joint is wet, leave the box empty and look again after two or three dry days. Still dry means rain or groundwater. Full again means there is more to find. For the longer version of the flow check, see our guide to the overnight water meter test.
| What you notice | Most likely cause | What to do |
|---|---|---|
| Box full after heavy rain, dry a few days later | Surface water getting past the lid | Clear the gully, level the ground beside the box. Nothing to repair. |
| Clear water that seeps back slowly and lingers all winter | Groundwater | Nothing to fix. Wipe the meter face to read it. |
| Droplets on the dial and a misted face only | Condensation | Wipe and read. Not a fault. |
| Box refills in dry weather, indicator still | Weeping meter coupling or a leak on the road side | Report it to South West Water. |
| Indicator turns, stops when the stop tap is closed | Leak inside the house | Book a leak survey. |
| Indicator turns with the stop tap closed | Leak on your supply pipe | Book an underground survey and tell South West Water. |
Which side of the meter is it?
This is the question that decides who pays, so it is worth being precise. South West Water is responsible for the communication pipe and the meter up to the boundary stop valve. The customer owns the supply pipe from that point into the property. In practice the meter box marks the boundary: the meter, its road-side coupling and the stop valve beside it are theirs; the house-side coupling and everything after it are yours. Our guide on a leak before or after the water meter goes through the responsibility line in more detail.
Two wrinkles catch people out. In some older Cornish houses the meter was fitted inside, under the sink, and the chamber at the boundary holds only a stop valve. The run from that valve to the indoor meter is still your supply pipe, even though it comes before the meter. And where one pipe feeds several homes, which is common on terraces in Redruth and Camborne and on farms that were split into cottages, the owners share responsibility for it between them.
When South West Water fix it and when it is yours
Theirs
A leaking meter, a weeping coupling on the road side, the boundary stop valve, the communication pipe and anything in the road or pavement. Report it through South West Water’s leak reporting page or their customer line, and send a photo if you can. They repair their own equipment at no charge to you. Do not tighten or dismantle the meter yourself: it is sealed, and it is not yours.
Yours
The supply pipe from the house-side coupling to your stop tap, and the plumbing beyond it. A leak here is yours to find and fix, and the water it wastes is on your bill until it is repaired. Two things soften that. South West Water offers a leak allowance on a first supply-pipe leak, subject to its conditions, so take a meter reading before the repair and another after, and read our guide to the South West Water leak allowance before you apply. Most UK buildings policies also include trace and access cover, which pays to locate a hidden leak and make good the damage caused by reaching it, though not the pipe repair itself.
Why Cornish meter boxes fill up so often
Cornwall gives meter boxes a hard time. Clay over granite holds water at the surface for weeks, winter rainfall is high, and many boxes sit in verges that flood every time the lane drains. Rural properties around Bodmin and Liskeard often have supply pipes running a hundred metres or more from the lane to the house, so the box is a long way from anywhere you would notice a wet patch. Holiday lets and second homes add their own twist: nobody lifts the lid between October and Easter, so a slow leak has a whole winter to run before the spring bill arrives. If your property stands empty, put a meter check on the changeover list.
If it turns out to be your leak
Resist the urge to dig along the pipe. A supply pipe is typically buried at least 750 millimetres deep, deeper under a drive, and the water rarely surfaces where the split is. A survey traces the pipe from the box to the house, listens along it with acoustic equipment, and where the pipe is plastic and quiet, uses tracer gas to find the exact escape point. The repair then needs one small hole. We provide leak detection across Cornwall, and the written report you get afterwards is the evidence South West Water and your insurer both ask for.
Frequently asked questions
Is it normal to have water in the water meter box?
Yes, some water is normal, particularly after rain or in a wet Cornish winter when groundwater rises. It becomes a concern when the box refills in dry weather, the meter is permanently submerged, or the flow indicator keeps turning while nothing in the house is using water.
Can water in the meter box damage the meter?
Modern meters are built to work wet and a submerged meter still records correctly. Standing water can make the face hard to read and, over years, corrode older fittings. If your meter is always under water, tell South West Water, as the meter and its couplings are theirs to maintain.
Will South West Water charge me for water leaking from the meter itself?
No. The meter and the pipe up to the boundary belong to South West Water, so a leak on the meter or its road-side coupling is repaired at their cost and the water is not charged to you. Water lost on your supply pipe, after the meter, does go through the meter and onto your bill.
How do I read the meter when the box is full of water?
Bail the water out with a jug or sponge, wipe the face with a dry cloth and shine a torch across it. Note the black digits, which are cubic metres, and the red digits or small dial, which show litres. If condensation mists the face again, give it a minute and wipe once more.
Who do I call if the box keeps filling up in dry weather?
Do the stop tap check first. If the flow indicator stops when your internal stop tap is closed, the leak is inside your home and a leak survey is the next step. If it keeps moving, or a joint on the road side is wet, report it to South West Water and ask them to inspect the meter.
Meter box refilling in dry weather?
If the flow indicator will not sit still and the box keeps filling, we trace the leak from the meter to the house without digging up the garden, and give you a report South West Water and your insurer will accept.
