Thames Water Leak Allowance Evidence: A Practical Document Checklist

A leak allowance application is easier to follow when the repair, dates and water-use records tell the same story. A pile of photographs may show dampness without establishing what was repaired. An invoice saying only “plumbing work” may leave the reviewer unable to distinguish leak detection from completed repair. The aim is clarity, not the largest possible attachment bundle.

This checklist is for organising a household Thames Water application after a leak. It explains the published starting requirements, then suggests practical ways to make your supporting account understandable. The suggestions are not a claim that Thames Water requires every document listed, and they cannot guarantee an allowance.

Start with the current household requirements

At the review date, Thames Water’s household allowance page says the leak must be repaired within four weeks of notification or identification, with the application made within three months of repair. It asks for a plumber’s details and invoice, or its own job number if it repaired the leak. Repairs under Section 75 are excluded in that guidance.

The page directs customers to complete the leak-fixed process before the allowance form, supply the requested readings and continue normal billing arrangements during review. Check that official page when applying, because procedures can change. Our main Thames Water allowance guide explains the overall scheme; this page concentrates on preparing the records.

Use the household route for a household account. Do not take a deadline from a business, wholesale or other supplier’s document and assume it applies. If the account type is uncertain, ask the company to identify the correct process before relying on a checklist found online.

Build an evidence folder around five questions

Organise the information so another person can answer: which property and account are involved, when the problem became known, what was found, what was repaired and what the readings show. These questions also reveal gaps early enough to request clarification from the contractor.

Folder item	What it should explain	Status in this checklist
Repair invoice and contractor details	Who completed the work and what the document relates to	Part of the published proof route for a private repair
Thames Water job reference	The company’s own repair attendance	Published alternative where it completed the repair
Reading record	Dates, meter identity and actual recorded values	Prepare for the information requested by the form
Timeline	Discovery, reports, investigation and repair sequence	Useful organisation aid
Supporting photographs or report	Context for the findings and completed work	Useful where relevant, not automatically mandatory

Name files in a way that makes their purpose apparent, such as “repair-invoice-21-September” or “meter-reading-22-September”. Keep originals and create a separate set for submission if you need to combine pages. Avoid replacing the original invoice with an edited screenshot that cuts off the contractor’s details.

Keep unrelated private information out of the bundle. An insurer’s entire correspondence file or a neighbour’s contact details may not be relevant to the water company’s enquiry. Supply the information the official process requests, and seek clarification if you are unsure what a follow-up request means.

What makes a repair invoice useful?

Before the contractor leaves, ask how and when the invoice or work record will be supplied. Explain that you may need evidence for a water-billing enquiry. This is a request for accurate documentation, not for the contractor to certify that the allowance will be approved.

A clear record should let you identify the property, work date, contractor and work undertaken. If several tasks appear on one invoice, ask that the leak-related work is distinguishable from unrelated servicing or improvements. The question is what actually happened, not whether the invoice uses a particular marketing phrase.

For example, “attended to locate leak; repair not completed” describes an investigation. “Repaired leaking connection beneath kitchen sink; checked repaired connection afterwards” describes a different outcome. These are illustrative descriptions only. The contractor should use wording that reflects their actual findings and checks, rather than copy an example that does not fit the visit.

Detection, access and repair may have different dates

If the first visit located a concealed leak and a later visit repaired it, retain both records. Label which document confirms completion. Opening a floor, tracing a route or temporarily isolating a pipe is not automatically the same as completing the permanent repair.

Our leak detection versus repair guide explains why the booking scope matters. If a contractor only provided detection, ask who is responsible for the next stage and what evidence will be available after it. Do not submit the detection date as the repair date simply because it is the first invoice you received.

Ask for clarification without altering the record yourself

If an invoice is vague, request an accurate supplementary note or corrected invoice from its issuer. Keep both the original and the clarification. Do not add statements about findings, completion or testing to a contractor’s document yourself.

A useful request could read: “Please confirm the attendance address, the actual repair completion date, the leak location you identified, the work carried out and any checks recorded after completion. I am preparing a water-billing enquiry and want the record to match your findings.” This asks for facts without coaching the contractor towards an unsupported conclusion.

Prepare meter records that can be interpreted

Record the date and time of each reading and retain a clear photograph where the meter can be reached safely. Include the meter identifier if visible and check that you are looking at the meter associated with your account. In a shared cupboard, do not choose one solely because it is nearest your flat’s label.

Follow the supplier’s instructions for reading that meter type. Do not silently mix whole cubic metres, smaller decimal digits and calculated litres in one column. If you make a conversion for your own notes, retain the original display value alongside it so the arithmetic can be checked.

Where online account records are available, save the relevant dated information and distinguish actual readings from estimates shown on a bill. A billed estimate and a photographed reading are not interchangeable evidence. If a figure is unclear, describe the uncertainty instead of replacing it with a more convenient number.

How to present a simple reading log

Use columns for date, time, meter identifier, value, source and relevant context. Context might include that the property was occupied normally, that the repair had just been completed or that a contractor took the reading. Do not invent a pre-leak baseline if none was recorded.

For a sequence spanning several days, make sure you compare values from the same meter. If the meter was changed, retain the exchange record and identify the old and new readings separately. Do not subtract the new meter’s starting value from the old meter’s final value as though the register continued unchanged.

Thames Water’s household leakage code describes using readings and, where available, smart-meter account information to notice changes in use. Treat your log as supporting information for assessment, not as a private calculation that binds the company to a particular credit.

What a short leak check can and cannot show

Thames Water’s identifying-leaks guidance describes an isolation-and-reading check aimed at the supply section between the meter and internal stop valve. Record the conditions if such a check was performed, including which valve was closed and whether other water use was excluded.

Do not describe one brief unchanged reading as proof that every pipe and fitting is leak-free. The result only concerns the conditions and period observed. Intermittent symptoms, shared supplies and uncertainty about isolation may require a more careful investigation. Ask the contractor to explain the scope of any post-repair check.

Keep the important dates separate

The date a high bill arrived, the date you noticed a symptom, the date a leak was confirmed and the date it was repaired may all differ. Keep each event with its supporting message, photograph or job record. Do not compress the whole sequence into a single convenient date.

If you do not know when the leak began, say so. You can still explain when you first became aware of it and what you did next. A contractor may be able to document a condition found during attendance, but should not be asked to assign an unsupported start date months earlier.

Invoice issue dates also need care. An invoice emailed on Friday may relate to work completed on Tuesday. Where that difference matters, ask the contractor to make the work date clear. Do not assume the payment date establishes when water loss stopped.

Delays, temporary measures and further attendance

If there was a delay obtaining access or completing repair, retain the correspondence and explain the facts. Do not hide an earlier notification or describe temporary isolation as permanent completion. The company decides how the circumstances affect the application; clear records allow it to consider what actually happened.

If a further leak is found after the first repair, keep it identifiable. Record the new finding, location and work date rather than rewriting the first invoice’s history. Ask Thames Water how it wants the sequence presented if the allowance period or completion status becomes unclear.

Photographs: useful context, limited proof

A wide photograph can show where the repair was made; a closer one may show an accessible defect or completed connection. Give each image a short factual caption and date. “Damp patch beside kitchen cupboard before attendance” is more defensible than “proof of six months of underground leakage” when no such duration was established.

Do not delay urgent work or expose yourself to water, unsafe floors or electrical hazards for a photograph. If a defect was concealed and the contractor has relevant images, ask whether copies can be included with the work record. Explain the purpose and avoid asking them to reconstruct a photograph after the repair.

A photograph rarely establishes the whole claim on its own. Pair it with the appropriate report and timeline. Conversely, a missing photograph does not justify inventing one or treating the claim as automatically impossible; ask the company what evidence it will accept in your circumstances.

Shared supplies, rented homes and separate cost questions

Thames Water’s responsibility guidance distinguishes its mains and communication pipe from private supply and internal plumbing, and explains that shared supply sections can involve joint responsibility. Identify the affected property and supply arrangement accurately rather than assuming the meter position settles every ownership question.

For rented accommodation, tell the landlord or agent promptly and retain the repair correspondence. Keep the water account enquiry and the arrangements for authorising repairs clear. If several parties hold different documents, ask for the relevant copies early enough to prepare the application.

A water-charge allowance is separate from the plumber’s bill and any insurance claim. Our trace-and-access insurance guide covers investigation and policy questions. Do not submit one provider’s approval as proof that a different provider must reimburse another category of cost.

Before submitting and after sending

Read the current official instructions, complete the requested fields and check that the attachments open correctly. Make sure the property, dates and readings agree across the form and supporting records. If something is uncertain, explain it plainly rather than choosing a precise answer without evidence.

Save a copy of what you sent and any acknowledgement or reference. If additional information is requested, respond to the identified gap and retain that response with the original submission. Avoid sending several conflicting versions without explaining which one corrects an earlier error.

If you still need a leak investigated or repaired, contact our London leak detection service and explain the current stage. Ask what work and written records the proposed visit includes. Good documentation can make an enquiry clearer, but the repair provider cannot promise Thames Water’s decision.

Common evidence questions

What if I repaired the leak myself?

Ask Thames Water what it will accept for your circumstances. Keep genuine receipts, photographs and dates, but do not create a plumber’s invoice or imply that a professional attended when they did not. The published private-repair proof route should not be replaced with an invented document.

What if the plumber has not sent the invoice?

Request it promptly and keep the actual completion date recorded. If a deadline is approaching, contact Thames Water about the missing document and the submission process. Do not assume waiting for paperwork automatically extends any deadline.

Should I wait until the next bill arrives?

Check the application deadline against the actual repair date, not the next expected bill. Use the official route to clarify anything missing. Retain your submission record so you can show what was provided and when.

If the allowance is refused

Our rejected leak-allowance guide explains how to identify the decision reason, respond with relevant evidence and follow the official review process. Clarify what is missing before paying for another inspection or report.