Thames Water Leak Allowance Form: Two Forms, Two Deadlines

A hidden leak on a metered supply keeps billing you for every litre that escapes, usually for months before anything visible appears. On a buried run that is a job for supply pipe leak detection rather than anything you will spot from inside the house. The leak allowance is the mechanism that puts part of that money back, and Thames Water does grant it. What catches people out is the paperwork, because the claim is not one form, and it cannot be completed on the day the repair is done.

This guide covers what the leak allowance form asks for, the form that has to come before it, exactly what the plumber's invoice needs to show on its face, why two meter readings taken a fortnight apart are part of the claim, and the two deadlines that end it regardless of how genuine the leak was. We are an independent London leak detection company and are not connected to, or acting on behalf of, Thames Water. Everything here is drawn from their published conditions, and the current wording on their own site is always the version that counts.

There are two forms, not one

This is the single most common reason a claim stalls, and almost nobody mentions it. Thames Water's process runs in two steps. Once the leak is fixed you complete the leak fixed form, which tells them the repair has happened and closes the notification that started the four-week clock. Only after that do you complete the leak allowance form, which is the claim for the water itself. If you have not reported the leak yet, our guide on how to report a leak to Thames Water covers the step before both of them.

File only the second and there is often no repair on record to attach it to. File only the first and the enforcement risk goes away but no money comes back, because nothing has been claimed. The two forms do different jobs and both are needed.

• Step one, the leak fixed form. Confirms the repair happened, with the plumber's invoice attached.
• Step two, the leak allowance form. The actual claim for the cost of the water that escaped.
• Both are completed through Thames Water's own online route.
• Neither is granted on the strength of a phone call, however reasonable the story.

Is there a leak allowance form PDF to download?

Worth answering directly, because it is what most people type into Google. Thames Water's route is an online form reached from their leaks pages, not a downloadable PDF. Copies of older paper forms do circulate on document-sharing sites and they rank well, but a form pulled from a third party can be out of date on the conditions, on the evidence required and on where it is meant to go. If Thames Water has posted you a paper form directly, use that one. Otherwise the online version is the one that will actually be processed.

What the leak allowance form asks for

The form itself is short. Every field on it is somewhere a claim can fail, and Thames Water's own instruction is to complete all parts of it, including the meter readings. An incomplete form is the most avoidable rejection there is.

• The account and the property the claim relates to.
• Details of the leak: where it was, when it was found, and how it was found.
• The date the repair was completed. Every deadline is measured from this date, not from the date of the letter.
• The plumber's details and invoice, or a Thames Water job number if they carried out the repair themselves.
• Meter readings covering the period before, during and after the leak. If you have never taken one, reading your water meter to check for a leak walks through it.

The invoice: four things it has to show

An invoice that says "plumbing work, paid in full" is the next most common reason a claim comes back. What is being asked for is evidence that a specific repair happened at a specific property on a specific date, and the invoice has to carry all of that on its face rather than in someone's memory.

• The address of the property where the work was carried out.
• What was actually done, described specifically. A supply pipe leak repair, not "plumbing".
• The date of the repair, because the claim window runs from it.
• The contractor's contact details, so the work can be verified.

If your invoice is missing any of those, ask for it to be reissued before you submit anything. It is a five minute request to the contractor and it is considerably faster than a rejected claim and a resubmission.

Two meter readings, taken at least two weeks apart

This is the detail that changes when you can claim, and it is the one people are most surprised by. Alongside the historic readings, Thames Water asks for two readings taken at least a fortnight apart after the repair. The purpose is to show that consumption has come back to normal, which is what demonstrates the leak is genuinely gone rather than partially patched or replaced by a second one.

The practical consequence is that a complete claim cannot be submitted the day the plumber drives away. Take a reading when the repair is signed off, put a note in your calendar, take the second one two weeks later, and submit with both. That second reading is the step most often forgotten, because by then the crisis is over and the leak has stopped being the thing on your mind.

Two deadlines, and both of them are hard

The allowance is governed by two separate clocks, and missing either one ends the claim on its own. They are measured from different events, which is exactly why people miss them.

• Four weeks to repair. Measured from the date Thames Water first notified you, or from when the leak was identified. Not from when you got round to calling someone.
• Three months to claim. Measured from the date of the repair, and it runs even if no bill has arrived yet. Waiting for the bill before claiming is a common and expensive mistake.

The second deadline catches more people than the first, because the urgency disappears the moment the water stops. The repair gets done inside four weeks, the household moves on, and the claim window closes quietly in the background.

The four conditions, in plain terms

Thames Water sets out four things that all have to be true. There is no partial qualification: fail one and the claim fails.

• The property is on a water meter. Unmetered properties are billed on rateable value and have nothing to rebate.
• The leak was repaired within four weeks of the notification or of it being identified.
• Evidence of the repair is provided, which in practice means the invoice above.
• The leak was not fixed under Section 75 of the Water Industry Act.

If you are not yet sure the leak is even yours to repair, the boundary is the stop tap at the edge of the property, and who is responsible for a Thames Water leak sets out which side of it you are on.

The one repair route that voids the claim

Section 75 of the Water Industry Act 1991 lets the water company carry out a repair on private pipework itself and recover the cost from the customer when the leak has not been fixed in time. It is what happens at the end of the four-week window if nothing else has.

It costs twice over. Their rates apply rather than a contractor you chose and priced, and a repair carried out that way is specifically excluded from the leak allowance, so the water you lost stops being recoverable at the same moment the repair stops being yours to arrange. If you have had a letter, the cheapest thing you can do is book the survey while the letter is still fresh. We cover what that letter means and the clock it starts on our page about a Thames Water leak letter and Section 75.

What the allowance pays, and what it does not

The allowance is a credit for the cost of the water that escaped. It is not a refund of your whole bill and it is not a contribution towards the repair. Thames Water works it out by comparing what you used in a comparable earlier period against what the meter recorded while the leak was running, then credits the difference. Where there is no usage history to compare against, they apply typical consumption for a similar sized property.

That method has a consequence worth understanding before you form an expectation. If the leak ran for a long time the credit can be substantial, and if it ran briefly it will be modest. Where the first sign was the bill rather than a letter, a high Thames Water bill and how to check for a hidden leak covers the diagnosis end of it. The number is arithmetic on your own meter, not a negotiation, which is why accurate readings matter more than a persuasive covering note.

A leak allowance is not an insurance claim

These two get conflated constantly and they cover completely different things. The allowance deals with the water that was lost, and it comes from the water company. Your home insurance deals with the damage the water did to the building and its contents, and many policies also include trace and access cover, which pays for the work of finding the leak in the first place.

They are not alternatives. On a supply pipe leak that soaked a floor, the allowance addresses the metered water, the insurance addresses the floor, and the trace and access element addresses the detection fee. Running both is normal and neither one prejudices the other, and our page on insurance leak claims covers what an adjuster actually wants to see. What they share is that both are decided on evidence, which is why one properly documented visit tends to serve both.

Where detection fits, and the part you cannot do yourself

Almost every field on the form is something you can supply. Two are not. The invoice has to come from whoever did the work, and the meter readings have to be right, because they are the arithmetic the credit is calculated from.

That is also the point at which the leak has to be found, and found properly, which is what a leak detection survey is for. Across our last 400 leak detection surveys we located the cause of the leak in 95 per cent of them. In another 2 per cent the water was coming from a neighbouring property rather than the one we were called to, and in the remaining 3 per cent it was not a plumbing leak at all but gutters, roofs or other structural defects letting water into the building. The final five per cent were not unsolved cases. They were cases where the answer was somewhere nobody had thought to look, and where digging up the client's own garden would have found nothing.

Behind a metered high-usage notification the odds tilt firmly towards your own supply, because a meter recording continuous flow is measuring water passing through your pipe. But the discipline is the same either way: confirm the source before anything is opened up, then document it. On buried pipework that means acoustic detection and, where plastic pipe deadens the sound, tracer gas. We record the meter at the start and end of the visit as a matter of course, and the invoice and detection report are written to be forwarded straight on rather than explained over the phone.

What to do, in order

1. Confirm the leak at the meter. Turn everything off, including appliances mid-cycle, read the meter, wait thirty minutes and read it again. Movement with nothing running is a leak.
2. Write down that reading and the date. It becomes the "during the leak" evidence later, and nobody can reconstruct it afterwards.
3. Get the leak located and repaired inside four weeks. The clock started at the notification, not at your first phone call. Our hourly rates are published, and detection is not charged if we cannot find the leak.
4. Check the invoice before you pay it. Address, specific work, repair date, contractor contact details.
5. Take a meter reading on the day of the repair. Then diarise the second one.
6. Take the second reading two weeks later. This is the step that gets forgotten.
7. Submit the leak fixed form, then the leak allowance form, inside three months of the repair date, without waiting for a bill.