Thames Water work FAQs
Straight answers to the questions we get asked most about Thames Water, WaterSafe and supply pipes.
Thames Water Work in London by WaterSafe Approved Plumbers
Leaking pipes, new stop cocks, new supply pipes, lead pipe replacement and Thames Water developer services applications. Because we are WaterSafe approved, we certify our own work. You do not need to wait for a Thames Water inspection.
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✓WaterSafe approved
✓Certificate of Compliance with every job
✓No Thames Water inspection needed
✓London, inside the M25
WaterSafe approvedThe scheme Thames Water tells its customers to use
Self-certified workNo open trench waiting for an inspector
Four week ruleWe help you fix leaks inside Thames Water's deadline
London onlyEvery job inside the M25
THAMES WATER'S GUIDE TO PIPE RESPONSIBILITY, IN PLAIN ENGLISH
Which pipe is yours, and which is Thames Water's?
Thames Water looks after the pipes under the road and pavement. You look after everything from your property boundary into your home. Most leak disputes come from not knowing where that line sits, so here it is.
Thames Water's pipes
Your pipes (the property owner)
Thames Water's side
The water main under the road, and the communication pipe that runs from the main to the outside stop valve at your boundary. If either of these leaks, Thames Water fixes it. Report leaks in the road or pavement to Thames Water, not to a plumber.
Your side
The supply pipe from the boundary into your home, usually under your garden or driveway, plus the inside stop valve and every internal pipe, tap, toilet, tank and appliance. It is still your pipe even if it crosses a neighbour's land or runs under the road.
Shared supplies and rented homes
Many older terraced houses share one supply pipe. You and your neighbours are jointly responsible for the shared section, and each of you for the branch that only feeds your home. Thames Water does not get involved in neighbour disputes. If you rent, your landlord is responsible: tell them in writing and keep a copy.
This is a simple summary of Thames Water's own guidance. Read the original on the Thames Water pipe responsibility page.
LEAK REPAIR RESPONSIBILITY
What Thames Water expects you to do about a leak
Thames Water now finds leaks with sensors and satellite data, so a letter or email can arrive before you have noticed anything. Here are the rules that matter, and how we fit in.
1. Fix it within four weeks
Whether you find the leak or Thames Water tells you about it, you must arrange the repair within four weeks. Common signs are damp patches, low pressure, or a higher bill if you are on a meter.
2. Miss the deadline and Thames Water steps in
Under Section 75 of the Water Industry Act 1991, Thames Water can carry out the repair and charge you for it. In an emergency they can turn off your supply until it is fixed.
3. Use a WaterSafe approved plumber
This is Thames Water's own recommendation. If you use a plumber who is not approved, Thames Water may come out to check the work and charge you for any extra repairs they think are needed.
4. Claim your leak allowance
Fix the leak within four weeks and you may be able to claim the cost of the lost water. On a meter, Thames Water compares your past use with the leak period. Our Certificate of Compliance is the paperwork that backs the claim.
5. Tell Thames Water it is fixed
Once the repair is done, let Thames Water know using their online fixed leak form so they can close the case and confirm it was done in time. We will remind you and give you what you need.
6. Check your home insurance first
Some buildings policies cover emergency plumbing or leaks. If yours does, your insurer may arrange and pay for the repair. If not, call us and we will get it sorted inside the deadline. For a leak that is flooding the house right now, our emergency plumber service runs 24 hours.
WHAT WE DO
Thames Water related work we carry out
Everything below is on your side of the boundary. Every job comes with a WaterSafe Certificate of Compliance.
Internal stop cock installation
New or replacement inside stop valves, plus the drain valve Thames Water expects to see next to it. Seized, leaking or missing stop cocks fixed properly.
Read more →Leaking pipework repair
Dripping taps, leaky loos, weeping joints and burst pipes anywhere inside your home. Repaired to the Water Fittings Regulations, with the certificate you need for a leak allowance claim.
Read more →Visual leak detection
A methodical check of your meter, stop valves, visible pipework and fittings to find the leak and tell you whose side of the boundary it is on.
Read more →New water supply pipe
New blue MDPE supply pipe from your home to the boundary, laid to Thames Water's rules in a trench you have already opened. We do not dig or reinstate.
Read more →Lead pipe replacement
Replace your lead supply pipe and Thames Water will replace its lead communication pipe for free. We do your side and issue the certificate that unlocks the scheme.
Read more →Developer services applications
We manage your Thames Water new connection application from estimate to certificate, so your new build, conversion or supply separation is not held up by paperwork.
Read more →
INTERNAL STOP COCK
Internal stop cock installation and replacement
Your inside stop valve is the tap that turns off all the water to your home. It is usually under the kitchen sink or where the supply pipe comes through the wall. Old ones seize up, weep from the gland, or were never fitted at all. When there is a leak, a stop cock that will not turn is the difference between a puddle and a flooded floor.
We fit new full-bore stop valves and replace old ones, and we can move the valve somewhere you can actually reach. We also fit the approved drain valve next to it, which Thames Water lists as a requirement whenever a supply pipe is reconnected or replaced. There is more on common faults on our stopcocks page.
Most stop cock jobs are done in one visit at our standard call-out rate. Book online or call 020 3764 2713.
What we do
- Fit or replace the inside stop valve
- Fit an approved drain valve upstream of the stop valve
- Insulate and duct the pipe where it enters the building
- Replace the short section of pipework around the valve if it is lead, corroded or leaking
- Issue a WaterSafe Certificate of Compliance
LEAKING PIPEWORK
Leaking pipework repair
Thames Water's own words for the common ones are "dripping taps and leaky loos". We repair those and everything else inside your home: weeping compression joints, pinholed copper, split plastic pipe, overflow pipes that never stop, cistern valves, tank connections and burst pipes. See also our pages on tap repairs and toilet repairs.
If Thames Water has written to you about a leak, the clock is already running. Tell us when you book and we will treat it as a four week deadline job, not a routine one. Every repair is done to the Water Supply (Water Fittings) Regulations 1999 and comes with a Certificate of Compliance, which is what Thames Water asks for when you claim a leak allowance.
Leaks on the supply pipe under your garden or driveway need the pipe exposing first. See new water supply pipe for how that works with us. If a pipe has just burst, read what to do if a pipe bursts in your home while you wait for us.
Good to know
- Same day and next day slots across London
- We photograph the repair for your records and your insurer
- Certificate of Compliance supports your leak allowance claim
- We tell you exactly what to send to Thames Water and where
VISUAL LEAK DETECTION
Visual leak detection
Before anyone digs, drills or lifts a floor, the leak needs finding. A visual leak detection visit is a structured check of everything you can see and test without breaking into the fabric of the building. It answers two questions: where is the water going, and whose pipe is it on?
We start at the meter and the outside stop valve, then follow the supply pipe route into the house, check every stop valve, tank, cistern, appliance connection and length of visible pipework, and look for the damp patches, staining and pressure drops that give a hidden leak away. It is the same approach we use for plumbing diagnostics generally, and it is where every leak repair should start.
We are honest about the limits. If the leak is underground or under a solid floor and cannot be found by eye or by a meter test, we will tell you so and explain the next step rather than guess and start digging.
What the visit covers
- Meter test: everything off, watch the meter, confirm whether water is still moving
- Outside stop valve and boundary box checked for standing water
- Inside stop valve isolation test to split the leak between the supply pipe and the house
- All visible pipework, fittings, tanks, cisterns and appliance connections
- Written summary of what we found and whose responsibility it is
NEW WATER SUPPLY PIPE
New water supply pipe where the ground is already exposed
A new supply pipe runs from your inside stop valve out to the outside stop valve or boundary box at the edge of your property. Thames Water does the section from there to the main. You need a new one when the old pipe is lead, leaking, shared with a neighbour, or too small for the house.
We lay and connect the pipe on your side of the boundary to Thames Water's specification. We do not excavate and we do not reinstate. You, your builder or your groundworker open the trench, we lay the pipe, and because we are WaterSafe approved you can backfill straight away. There is no waiting with an open trench for a Thames Water inspector, and no risk of the second inspection fee (currently £185 plus VAT) that comes with a failed inspection.
Please note: we cannot work in the public footpath or road. That land needs Highway Authority consent and is handled by Thames Water as part of your connection.
What we do
- 25mm or 32mm blue MDPE for a house (or barrier pipe where Thames Water's quote requires it, for example near garages, petrol stations, railways or old industrial land)
- Laid at 750mm to 1350mm deep, bedded in soft stone-free material or ducted
- Tunnelled under boundary walls and fences, not through the footings
- Ducted and insulated where it enters the building
- Inside stop valve and drain valve fitted
- Enough pipe left at the boundary to reach the outside stop valve
- Certificate of Compliance issued and sent to Thames Water
What we do not do
- Digging, excavation or moling
- Reinstating driveways, paths, patios or lawns
- Any work in the pavement or road
- The final connection to the main (that is Thames Water's job once they have our certificate)
LEAD PIPE REPLACEMENT
Lead pipe replacement and the Thames Water scheme
If your home was built before 1970 there is a good chance the supply pipe is lead. Thames Water runs a Lead Pipe Replacement Scheme: if you replace your lead supply pipe from the boundary to your home, Thames Water replaces its lead communication pipe from the boundary to the main for free, like for like up to 25mm. Small old pipes of 12mm to 15mm are upgraded to the standard 25mm.
The scheme only works if your side is done to the Water Regulations and proven with a certificate. That is where we come in. We replace the lead supply pipe with 25mm blue MDPE in the trench you have opened, replace any lead pipe or lead solder inside the house, fit the inside stop valve and drain valve, and issue the Certificate of Compliance. You email that to Thames Water and their side goes into the queue.
Because we are WaterSafe approved there is no reconnection survey and no open trench waiting for an inspector.
How the scheme works
- 1. Check your outside stop valve and whether the supply is shared
- 2. Apply online to Thames Water. You must plan to replace your pipe within 3 months of applying
- 3. We replace your side and issue the certificate
- 4. You email the certificate to Thames Water. They ask for the subject line LPRapprovedplumbercertificate
- 5. Thames Water traces and marks its pipe, then replaces it. They aim to finish within 3 months of you qualifying, with the road or pavement reinstated within 2 working days of the work
Things to check first
- House built before 1966? Get an electrician to check your earthing. Old installations sometimes used the lead water pipe as the earth
- Shared supply? The free scheme does not cover separating it. That needs a new connection application, which we can manage
- Until the work is done, run the cold kitchen tap for about 2 minutes before drinking. On the first day after Thames Water finishes, run all drinking taps for 10 minutes
DEVELOPER SERVICES
Thames Water developer services application management
You need a Thames Water new water connection if you are building a new property, converting a house into flats, separating a shared supply, or upgrading an existing one. The application is not hard, but it has a lot of moving parts, strict deadlines, and non-refundable fees if you get it wrong or let a quote lapse.
We manage the whole thing for you. We check Thames Water is your supplier, build an estimate from their charging arrangements (updated every 1 April), put the application pack together, chase the quote, and then lay and certify your side of the pipework so the connection is not held up. If you are a managing agent or developer with several sites, our property managers page explains how we work across a portfolio.
We handle service connections from the main to your building. New water mains on larger sites are a separate piece of work done by Thames Water or a self-lay provider, and we can point you in the right direction.
What the application involves
- Water fittings table listing every tap, toilet and shower per property
- Point of entry drawing showing where the pipe meets the boundary
- Site map showing the property against the surrounding roads
- Storage tank form, soil report and barrier pipe where needed
- Plot to postal template with proof of the postal address from the council
Thames Water's timescales
- Quote issued within 28 days of a complete application and fee
- Quote valid for 6 months; paying it is your acceptance
- Pipework laid and certified within 12 months of the quote date, or a re-quote is needed
- Our certificate goes to [email protected] and takes about 5 working days to process
- Connection normally within 4 months of Thames Water agreeing permits with the council or TfL
WATERSAFE APPROVED CONTRACTOR
Why WaterSafe approval matters for Thames Water work
Thames Water closed its own approved plumber scheme in October 2022 and now points customers to the WaterSafe Register. Here is what that approval gives you.
We certify our own work
Approved contractors can carry out most work without giving Thames Water advance notice, and Thames Water accepts our certificate instead of sending an inspector. That means no open trench waiting for a visit and no delay to your connection.
Your legal protection
The Certificate of Compliance we issue is your evidence that the work meets the Water Fittings Regulations. If Thames Water ever questions it, the responsibility sits with us, not you.
Vetted, qualified and insured
WaterSafe businesses must carry at least £2 million public liability insurance, employ qualified plumbers with a Water Regulations qualification, and keep a recognised supervisor for every five people doing water supply work.
Recognised across the industry
The register is backed by every UK water company and the Drinking Water Inspectorate. Some contracts, including NHS guidance, specify WaterSafe approved plumbers. See our other accreditations and industry awards.
HOW IT WORKS
From first call to Thames Water sign-off
1
Tell us what is happening
Call, book online or send photos through the contact form. If Thames Water has written to you, tell us the date on the letter so we can work to the four week deadline.
2
Visit or quote
Stop cocks, leak repairs and visual leak detection are booked at our standard call-out rate. Supply pipes, lead replacement and developer applications get a written quote.
3
The work is done
Carried out by a WaterSafe recognised plumber to the Water Fittings Regulations and Thames Water's own checklist. For supply pipes, the trench can be backfilled the same day.
4
Certificate and sign-off
You get the Certificate of Compliance, and we tell you exactly which Thames Water team it goes to. For developer services jobs we send it for you and chase the connection.
Is PH247 a Thames Water approved plumber?
Thames Water no longer runs its own approved plumber list. It closed the TAPS scheme in October 2022 and moved to the national WaterSafe Register, which is what its website now tells customers to use. PH247 is WaterSafe approved, so we are on the list Thames Water points you to, and Thames Water accepts our certificates without an inspection.
Do I need a Thames Water inspection if I use you?
No. Because we are WaterSafe approved we self-certify. We issue a Certificate of Compliance and that is what Thames Water needs. If you used a plumber who is not approved, you would have to leave the trench open, book a Water Regulations inspection, and pay £185 plus VAT for a second visit if the first one failed.
Can you dig the trench for a new supply pipe?
No. We lay and connect the pipe once the ground is exposed, and we fit everything inside the house. Digging, moling, and reinstating driveways, paths or lawns are done by you, your builder or a groundworker. We are happy to tell them exactly what depth and route we need before they start.
Who pays for the pipe under the pavement?
Thames Water owns the communication pipe from the main to your boundary, so they fix and replace it. For a new connection you pay Thames Water’s quoted charge for that work. For lead pipe replacement, Thames Water replaces its lead pipe for free once you have replaced yours and sent them our certificate.
How long does Thames Water take to connect a new supply?
Thames Water aims to issue a quote within 28 days of a complete application. Once your pipework is laid and certified, they aim to connect within 4 months of agreeing permits with the local council or Transport for London. Busy roads that need traffic management can take longer. Your quote is valid for 6 months and all pipework must be laid and certified within 12 months of the quote date.
What size pipe do I need?
A typical house uses 25mm or 32mm blue MDPE. Thames Water’s quote will confirm the size for a new connection. Pipes of 63mm or more need chlorinating before connection, but that is rare for homes. Near garages, petrol stations, railways, cemeteries or old industrial land, Thames Water requires barrier pipe, which has a metal layer that stops contamination getting through the plastic.
I think I share a supply pipe with my neighbour. What are my options?
Signs of a shared supply are a stop valve in a communal area or poor flow at busy times like 7am to 8am. You and your neighbours share responsibility for the shared section. If you want your own supply, that is a new connection application to Thames Water developer services, which we can manage. Note that the free lead replacement scheme does not cover separating a shared supply.
Will Thames Water refund the water I lost through a leak?
Possibly. If you repair the leak within four weeks you can apply for a leak allowance. On a meter, Thames Water compares your normal use with the leak period. If you are not on a meter, they estimate it from a similar household. Thames Water asks for proof the repair was done properly, which is where our Certificate of Compliance comes in.
Which areas do you cover?
We cover London inside the M25 only, including Camden, Westminster, Battersea, Clapham, Fulham, Hackney, Greenwich and East London. If your property is outside the M25 we are not the right fit, and we would rather tell you now than waste your time.
Got a letter from Thames Water, or planning a new supply?
Book a WaterSafe approved plumber for leaks and stop cocks, or send us the details for a supply pipe, lead replacement or developer services quote.
Book a Plumber Call 020 3764 2713 Request a QuoteRelated services
PH247 also covers stopcock repairs, leak repairs, burst pipes, plumbing diagnostics and emergency plumbing across London. Managing agents and landlords can read about our property manager service and proactive maintenance plans, or browse all services.
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