A business water bill that has risen with no change in trading is often the only notice a commercial leak gives. TrueFlow provides commercial leak detection across Bracknell, Berkshire and the surrounding towns: non-invasive tracing with the same acoustic, thermal and tracer-gas instruments as our domestic leak detection service, a written finding you can hand to your water retailer, and a repair by the same engineers once the fault is found. Detection is quoted per site, free of charge.
What the bill is telling you
A metered bill that is high against the same period last year, with nothing in the business to explain it, is the first sign; that comparison is also the one a wholesaler uses to calculate an allowance.
The meter can confirm it. With the premises closed and every outlet idle, a reading at lock-up and another at opening should agree; if they do not, and no cleaning cycle, urinal flush or process plant ran overnight, the difference is a leak. Photograph both readings with the time showing. Our guide to how to tell if you have a water leak walks through the meter test step by step.
Routine-looking evidence counts too: a ceiling tile that stains again after replacement, a patch of car park that stays dark in dry weather. Beside a bill that has jumped it is a strong case, and since sewerage charges are normally a fixed share of the metered volume (90% for Thames Water), most of the leaked water is charged for twice until an allowance is agreed.
Locating it on a working site
Commercial pipework hides leaks well: long runs under car parks, several incoming supplies on a multi-let site, pipes above suspended ceilings and under screed. Detection therefore starts by closing zone valves and stop taps in turn while the meter is watched; the section that stops the meter is the section with the leak.
Then instruments go on that section. Acoustic listening picks up pressurised water escaping through concrete, tarmac or soil, and works best when the site is quiet, so business surveys often run outside trading hours. Thermal imaging shows where a hot water or heating run is warmer than it should be. Tracer gas suits the smallest leaks and plastic pipe that carries little sound: the section is drained, charged with a hydrogen and nitrogen mix, and a detector above finds where the gas rises. The result is a located fault, flagged on the surface and recorded in the report, so any opening-up is sized to it.
A written finding for your water retailer
Since the business retail market opened in April 2017, English businesses have chosen a retailer for their water and wastewater services (gov.uk). The retailer reads the meter and sends the bill; the wholesaler still owns the pipework, as the Consumer Council for Water explains. The retailer is also the only route to a leak allowance, a reduction in charges for the extra water a leak put through the meter.
The industry’s Leak Allowances Customer Guidance, an RWG document hosted by CCW, sets out the process: the business gives its retailer a claim form and proof of repair (the repair bill and/or, typically, two post-repair meter readings a couple of weeks apart, plus photographs of the leak and the meter), the retailer applies to the wholesaler, and the wholesaler decides. The RWG good-practice terms are repair within 30 days of becoming aware of the leak, a 12-month maximum, one allowance in any 24-month period, and nothing for negligence or leaking internal fixtures and fittings, but each wholesaler sets its own. Thames Water, for example, asks for the repair within six weeks of the leak being confirmed and a claim within six months of it, takes two post-repair readings about ten days apart, grants one allowance in 12 months, and only where the leaked water did not reach the sewer; some wholesalers credit water and sewerage, others sewerage only, so check with your retailer. Affinity Water’s non-household policy adds that a customer is deemed aware of a leak once the retailer or wholesaler tells them, including by a higher than average bill: the repair clock can be running when the envelope is opened.
TrueFlow’s report is written to fit that process: survey date, readings, method, the fault’s location with photographs and a sketch where the run is buried, the repair and its date, and post-repair readings where taken. TrueFlow does not submit the claim; the report means someone can show where the leak was and when it was fixed.
Whose pipe it is
The wholesaler owns the water main and the communication pipe up to the boundary, usually marked by its stop tap; the supply pipe from there into the building, and everything inside, belongs to the premises, which the RWG guidance puts as the customer or the landlord, so check the lease. Where one supply pipe serves more than one property, CCW’s guidance is that it is the joint responsibility of all the owners connected to it. A wholesaler that finds a leak on private pipework can serve a repair notice under Section 75 of the Water Industry Act 1991, so knowing which side of the boundary the fault sits on matters early.
Repair, priced before it starts
Once located, the same engineers can repair it, from a section of supply pipe excavated and replaced to a failed joint above a ceiling. The exact price is agreed before the repair begins, the work is fully insured and guaranteed for 6 months, and out-of-hours attendance is routine, as our commercial plumbing page sets out. Water escaping fast enough to be a hazard is an emergency rather than a survey: 24/7, a 60-minute response target, call-outs from £120 including VAT.
Quotes are free
Commercial leak detection has no published price because the search is sized to the site. The quote is prepared from the site details and symptoms, costs nothing, and is agreed before any work starts. Facilities teams can see how planned visits work on our offices and facilities management page.
Commercial leak detection FAQs
How do I know if my business premises has a leak?
Compare the bill with the same period last year and, if it has risen without a change in trading, read the meter at lock-up and again at opening. Overnight movement that no appliance or process explains is water leaving the pipework; a damp patch or ceiling stain that keeps returning strengthens the case.
Can a business claim a leak allowance on its water bill?
Often, but not automatically. Industry guidance hosted by the Consumer Council for Water says the claim goes through your water retailer to the wholesaler, which decides under its own policy and typically needs proof of repair, post-repair readings and photographs. Internal fixtures and fittings are generally excluded, and some wholesalers credit sewerage only, so ask your retailer.
Will the water wholesaler repair a leak on our supply pipe?
No. The wholesaler’s pipework ends at the boundary, usually at its stop tap, and the pipe on your side of that point is private: its repair falls to the premises, to the landlord, or, where one pipe serves several properties, to all the owners jointly, as the lease sets out. A wholesaler can serve a notice under Section 75 of the Water Industry Act 1991 requiring the leak to be fixed, so a located fault on the private side is best repaired before that letter arrives.
What should we have ready before a leak detection visit?
The last two or three bills, the meter’s location and any readings already taken, a plan of the incoming supplies and stop taps if one exists, and a note of what runs overnight: urinal flushes, cleaning cycles, process plant. On a multi-let site, the name of whoever can authorise valves being closed in turn. None of it is essential, but each item shortens the search and strengthens the report the retailer will see.
Why might a commercial leak need a second visit?
Usually because the leak only registers overnight, or because the first visit narrowed it to a section that has to be drained and charged with tracer gas, which cannot happen while the premises are open. More than one incoming supply, long buried runs under a car park and a meter that only moves when the building is empty all add time, so a large site may be traced in two stages; where a second stage is likely it is quoted at the outset rather than added afterwards.
Bring the last two bills
A rising water bill is evidence; a located leak turns it into a repair and a claim. Call TrueFlow on 0808 175 7440, any hour of any day, or request a callback with the site details and the last two bills.