Our Water Treatment Services in London
Chlorination and certification, Legionella risk assessment and control, water sampling, and cold water storage tank cleaning and replacement, for residential and commercial property across London.
- Chlorination and disinfection carried out in line with BS8558, with certification on completion
- Legionella risk assessment, sampling and control referenced to HSE guidance, ACOP L8 and HSG274
- Water samples analysed by a UKAS accredited laboratory
What water treatment services do we provide
London Water Treatment provides three connected services across London: chlorination and disinfection of mains, pipework and tanks with a certificate on completion; Legionella risk assessment, testing, monitoring, disinfection and remedial work; and water tank cleaning, inspection, repair and replacement. Water sampling through a UKAS accredited laboratory supports all three.
Every job comes down to the same thing. A water system has been built, altered, cleaned or left standing, and somebody has to prove it is safe. That proof is a method, a laboratory result and a certificate. Our guide explains what water treatment is if you want the background first.
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Chlorination and certification
Mains, new pipework and stored water systems disinfected, sampled and certified.
- Mains chlorination before connection
- Flushing and chlorination of new pipework
- Tank chlorination and remedial disinfection
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Legionella control
Risk assessment, sampling, monitoring and remedial work for hot and cold water systems.
- Risk assessments, same day available
- Sampling and laboratory analysis
- Disinfection and follow up monitoring
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Water tanks
Cleaning, inspection, repair and full replacement of cold water storage tanks.
- Cleaning and chlorination of stored water
- Lid, screen and insulation defects put right
- GRP, plastic and sectional tank replacement
Chlorination and disinfection
Disinfecting a system so it can be connected, handed over or brought back into use.
Chlorination is the controlled dosing of a system with disinfectant, held at a set concentration for a set contact period, then flushed back to normal supply quality and proved by laboratory sample. The work follows BS8558 and BS EN 806-4, and where the water is for drinking the Water Supply (Water Fittings) Regulations 1999 apply too.
- Mains chlorination The incoming supply pipe, external and internal, before the connection to the water main is made.
- New pipework Flushing and chlorination of internal distribution pipework on a build, fit out or renovation.
- Tank chlorination Cold water storage tanks and downstream pipework after cleaning, repair or replacement.
- Remedial disinfection Systems left standing, opened up for works, or that have failed a sample and need resampling.
Chlorination certificates
A chlorination certificate records that a named system was disinfected to the required standard on a given date, and that the post disinfection sample passed laboratory analysis. Thames Water and other undertakers ask to see one before a new or altered connection. We certify on completion and take last minute bookings where one is needed the same day. Method and timescales are on our chlorination services page, and our guide covers the chlorination certificate in full.
Legionella control
There is no single piece of legislation called the Legionella Act. The duty comes from the Health and Safety at Work etc. Act 1974 and the Control of Substances Hazardous to Health Regulations 2002, with the practical advice in the HSE's Approved Code of Practice L8, fourth edition 2013, and technical detail in HSG274. The dutyholder needs a suitable and sufficient assessment by a competent person, and has to act on it and keep records.
- Risk assessments A survey of the system, how it is used and who could be exposed, with a certificate setting out the level of risk and the recommendations. Same day assessments are available.
- Testing and sampling Samples taken from representative points and analysed by a UKAS accredited laboratory.
- Control and monitoring Temperature checks and outlet flushing regimes, so the control scheme is run and evidenced rather than assumed.
- Disinfection and remedial work Cleaning, flushing and chlorination of pipework and tanks, removal of dead legs, and the actions the assessment raises.
Review the assessment every two years, and sooner where the system is higher risk, has been altered or has stood unused. Our Legionella control services page covers it in full, and there is a separate guide to Legionella testing and water sampling.
Water tank services
Cold water storage tanks, from a routine clean to a full replacement.
A cold water storage tank is the part of a building's water system most likely to cause a problem, because the water sits still in it. Sediment settles, debris gets in through a poorly fitting lid, temperatures drift up in a warm roof space, and an unlined steel tank corrodes.
- Inspection Condition check of the tank, lid, screens, overflow, insulation and pipework, reported with recommendations.
- Cleaning Drain down, sediment removed, surfaces wiped down, refill and chlorination. The level of clean depends on the lid and jacket fitted, and we advise which applies.
- Repairs Tight fitting lids, insect screens, insulation and overflows corrected so the tank stops being a route for contamination.
- Replacement A corroded or undersized tank removed and a new GRP, plastic or sectional tank installed, then chlorinated and sampled.
The full range is on our water tank services page, with dedicated pages for water tank cleaning and water tank replacement covering what happens on the day and how long the water is off.
Water sampling and testing
Samples are taken from agreed points, kept in suitable conditions and delivered to a UKAS accredited laboratory. That accreditation matters, because the result was produced to a recognised quality standard and will stand up in an audit or a handover pack.
Two kinds of sample answer two questions. A post disinfection sample after chlorination confirms the water meets the microbiological quality expected of a supply fit for drinking, and that is what a certificate rests on. A Legionella sample is separate, taken to the sampling standard BS 7592 and reported as colony forming units per litre, and it takes around seven to ten days because the bacteria have to grow before they can be counted.
If a post disinfection sample fails, no certificate is issued. We investigate, disinfect again and resample. For how the services fit together, see our explainer on what water hygiene services cover.
Who we work with
Residential and commercial, across London and the surrounding areas.
We work for whoever holds the duty on the building, and that changes from job to job.
- Building contractors and mechanical and electrical subcontractors needing pipework flushed, chlorinated and certified before handover
- Developers commissioning new houses, apartment blocks and mixed use schemes
- Landlords and letting agents assessing the Legionella risk in a let property
- Managing agents responsible for communal cold water storage
- Facilities managers running control schemes in occupied buildings
- Private home owners with a tank that needs cleaning or replacing
Worth knowing if you are a landlord or an agent: a duty under section 3 of the Health and Safety at Work etc. Act 1974 cannot be passed on by means of a contract. You can appoint a competent contractor, but responsibility for making sure the work is done stays with you.
How a job runs from first call to certificate
- First call Tell us the property type, the system, and the date any certificate is needed by. That last point drives the programme.
- Scope and book We confirm the work, the access and isolation needed, and how long the water will be off, then give you a quote and a date. Where the system has to be seen first, we survey before quoting.
- Works on site Cleaning, flushing, dosing and the required contact period, then flushing through to normal supply quality. On a tank job, drain down, clean and refill.
- Sampling Samples go to a UKAS accredited laboratory. Nothing is certified before the result is back.
- Report and certificate You receive the laboratory result and the certificate or assessment report electronically, with recommendations and remedial actions in writing. If a result does not pass, we tell you what needs to happen and quote for the remedial work.
Book a service or ask a question
Tell us the system, the property and the date you need the certificate by, and we will tell you what is involved. Call 020 4532 7773, email info@londonwatertreatment.com, or request a quote online.