A leak letter from South West Water means your meter recorded water flowing when the house should have been using none. The leak is most often on your supply pipe, which is your responsibility from the boundary in. Confirm it at the meter, find it, repair it by the date on the letter, then apply for the leak allowance.
The letter says South West Water believe there is a leak at your property. You have walked round the house, looked under the sinks and along the skirting, and everything is dry. Now there is a date on the page and a vague sense that you are in trouble. You are not. The letter is a prompt, and it usually arrives well before the leak has done any damage. Cornwall Leak Detection Specialists is an independent company, not part of South West Water, and we spend much of our week finding exactly the leaks these letters describe. This guide explains why they wrote, which sort of letter you have, and what to do in order. When you are ready for the finding part, our approach to locating a hidden water leak is on the service page.
Why South West Water think you have a leak
They are not guessing. Three things trigger the letter, and it helps to know which one applies to you.
- A meter reading that jumped. Your latest read was far above the pattern for your household, with nothing on the account to explain it. On a metered supply that is the first flag.
- Continuous night flow. Newer meters can be read remotely, and some log flow through the night. A house that draws water at three in the morning, every morning, is either running a very keen dishwasher or has a leak.
- A meter reader saw the dial turning. If the reader lifts the lid and the flow indicator is moving while the house looks empty, they note it. You may get a card through the door rather than a letter.
Whichever it was, the message is the same: water is passing through the meter at times you are not using it. That is a fact about flow, not yet a fact about where the leak is.
Which letter you have
Read it twice, because there are two kinds and they carry different weight.
A courtesy notification tells you usage looks high and asks you to investigate. There may be a suggested timescale, but the tone is advisory. Most first letters are this type.
A formal notice under section 75 of the Water Industry Act 1991 is a legal document. It requires you to repair a leak on your pipework within the period printed on it, and if you do not, the company can carry out the work and recover the cost from you. That route is nearly always dearer than arranging your own repair. If your letter quotes section 75, put the date in your diary and start today. Even if it does not, work as though the date is firm. Water lost between now and the repair is on your bill.
Prove it for yourself tonight
Before you ring anyone, confirm the leak with your own eyes. Turn off every tap and appliance, let the cisterns finish filling, and look at the meter. The small wheel or triangle on the face should be still. Write down the reading, including the red digits, go to bed, and read it again before anyone showers. Our guide to the overnight meter test, step by step covers the detail and the arithmetic. Then close the internal stop tap and check once more. If the indicator stops, the leak is inside the house. If it carries on, it is on the buried supply pipe between the meter and your stop tap. Now you know something the letter does not: which half of the system to look in.
What to do, in order
- Note the type of letter and the date. Photograph the letter and the meter reading on the day it arrives.
- Do the overnight test and the stop tap test. You will be asked for the results by everyone you speak to.
- Ring South West Water on the number in the letter. Tell them what the meter did, ask whether they consider the leak to be on their side or yours, and ask what help is available for a supply pipe repair. Schemes exist for homeowners; the amounts and conditions change, so get the current terms from them rather than from a website.
- Check your buildings policy for trace and access. Ring the insurer before any floors or ground are opened.
- Have the leak located before anyone digs or lifts anything. A letter tells you there is a leak. It cannot tell you which metre of pipe.
- Get it repaired by a competent plumber, ideally one on the WaterSafe register, and keep the invoice.
- Take a meter reading after the repair and apply for the allowance.
Whose pipe, whose bill
South West Water are responsible for the water main, the communication pipe and the meter up to the boundary stop valve. You own the supply pipe from that point into the house and everything inside it. Because the letter is about flow through the meter, the leak is almost always on your side of that line, which is why they wrote to you rather than sending a gang to the road.
One exception is worth raising on the phone. If your supply pipe is shared with neighbours, as many Cornish terraces and converted farm buildings are, the owners share responsibility for the shared length. Agree early who is coordinating the repair and keep it in writing.
On the bill itself, South West Water offer a leak allowance on a first supply-pipe leak, subject to their conditions. It credits some of the water lost through the leak once it has been repaired, which is why the before and after readings matter so much. The leak allowance rules and how to apply are covered in our separate guide.
Where insurance fits
Most UK buildings policies include trace and access cover. It pays to find a hidden leak and to make good the damage caused by getting to it, such as lifting a floor or opening a drive and putting it back. The limit is often in the £5,000 to £10,000 range. It does not pay to repair the failed pipe, which insurers treat as wear and tear. Read what trace and access cover pays for before you ring, then ask your insurer whether you can appoint your own specialist. A written survey report with the leak marked, photographed and explained is what the claims handler wants to see.
The Cornish complications
Two patterns come up again and again here. The first is the long rural run: a farmhouse near Launceston or a cottage above Fowey with a supply pipe that crosses a field before it reaches the house. Nothing surfaces, the meter is by the lane, and the letter is the first anyone knows. The second is the second home. The letter goes to a billing address in another county, sits on a doormat for a month, and the deadline is half gone before it is opened. If you let or own a property that stands empty, ask South West Water to send correspondence by email as well, and ask your cleaner or keyholder to glance at the meter at changeover. We provide leak detection throughout Cornwall, including properties where the owner is not on site, and can work with a keyholder.
Frequently asked questions
South West Water said I have a leak but I cannot see one. Is the letter wrong?
Rarely. The letter is based on water passing through your meter at times the house should be using none. Most supply pipe leaks are underground and never show at the surface, and many internal leaks run under a floor. Do the overnight meter test yourself to confirm before you go further.
How long do I have to fix the leak?
The period is printed on your letter, and that is the figure that counts. A formal notice under section 75 of the Water Industry Act 1991 sets a legal deadline, after which the company can do the work and bill you. If you cannot meet it, ring them before it passes and explain.
Will South West Water find the leak for me?
They may offer a short visit to check the meter and confirm which side of the boundary the leak sits on, but locating a leak along a buried supply pipe or under a floor is specialist work. Ask what they offer when you ring, and use an independent survey for the precise location.
Do I have to use a WaterSafe plumber for the repair?
You are not usually obliged to, but South West Water may ask for an invoice from a competent plumber before paying an allowance or a contribution, and WaterSafe is the recognised register of approved plumbing businesses. Using one keeps the paperwork simple and the repair to the current water regulations.
Will my bill be reduced for the water that leaked?
Often, yes. South West Water offer a leak allowance on a first supply-pipe leak, subject to their conditions, which credits some of the water lost once the leak is repaired. You need meter readings before and after the repair and proof it was done, so keep every receipt and photo.
Letter in hand, leak unseen?
We locate the leak South West Water have flagged, on the supply pipe or inside the house, without digging on a guess, and give you the written report your allowance claim and your insurer both need.
