Is chlorination a legal requirement in London?

Yes, in specific circumstances. BS 8558 requires chlorination for new installations, systems that have been substantially modified, and systems found to be contaminated. ACOP L8 also requires disinfection as part of remedial action when legionella or other contamination is detected in your London property.

Who is responsible for arranging chlorination in London?

The building owner, landlord, or duty holder with operational control of the water system is responsible. For new-build projects in London, the contractor commissioning the system must ensure it is chlorinated before handover.

How long does chlorination take?

A typical chlorination in London takes 4–8 hours including contact time, flushing, and sampling. Larger or more complex systems may require overnight treatment. We aim to minimise disruption and restore your water supply as quickly as safely possible.

What happens if chlorination reveals a problem?

If post-treatment sampling at your London property shows that contamination persists, we investigate the root cause — this may include further system inspection, repeat treatment, or recommendations for pipework modifications to eliminate the source.

What chlorine concentration is used during treatment?

We follow BS 8558 guidelines, typically using 50 mg/l for a minimum one-hour contact time, or 20 mg/l for two hours. The exact dosing depends on the system and the nature of the contamination. After treatment, we flush until residual chlorine falls below 0.5 mg/l.

Chlorination in London

Q: How much does chlorination cost in London?

Pricing depends on the system size and urgency. Routine chlorination for a small London system starts from around £300, while emergency or large-scale treatments are quoted individually. Contact us for a free estimate based on your specific requirements.

Fast, professional water system disinfection for contamination events, new installations, and planned maintenance.

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Is Chlorination a Legal Requirement?

Chlorination is required under BS 8558 whenever a water system is newly installed, substantially altered, or found to be contaminated. ACOP L8 also requires that contaminated systems are disinfected before being returned to service. Failure to disinfect can leave you exposed to prosecution under health and safety legislation.

The duty to ensure disinfection falls on the building owner, landlord, or whoever has operational control of the water system. Contractors commissioning new systems also have a responsibility to chlorinate before handover.

Chlorination is the most effective method for disinfecting contaminated water systems. Whether you're dealing with a legionella outbreak, a failed water test, or commissioning a new system, our engineers deliver rapid chlorination across London. We handle everything from emergency call-outs to planned maintenance disinfections, ensuring your water supply meets all safety standards.

What's Included

System Assessment

Initial assessment of the water system layout and contamination level before treatment.

Controlled Chlorine Dosing

Precise dosing of chlorine to the correct concentration per BS 8558 guidelines.

Contact Time Management

Monitored contact period to ensure effective disinfection throughout the system.

Full System Flush

Complete flushing and neutralisation to remove residual chlorine after treatment.

Post-Treatment Sampling

Water samples taken after chlorination to confirm the system is safe for use.

Disinfection Certificate

Written certificate confirming the chlorination was carried out to required standards.

Our Process

Get a Quote

Call us or fill in our form — for emergencies we aim to respond within 1 hour.

Site Visit Booked

We confirm a date and time, or for emergencies, attend the same day where possible.

System Isolation

We safely isolate the affected sections of your water system before treatment.

Chlorination Treatment

Controlled dosing and monitored contact time to disinfect the entire system.

Flush & Sample

Full system flush followed by water sampling to confirm safe chlorine levels.

Certificate Issued

Disinfection certificate issued and your water supply cleared for normal use.

How Much Does Chlorination Cost?

Pricing depends on the system size, urgency, and complexity. Routine chlorination for a small system starts from around £300, while emergency or large-scale treatments are quoted individually. We'll provide a fixed-price quote within 1 working day — no obligation.

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Common Issues We Find

•Positive legionella test results requiring urgent disinfection
•Contaminated water supplies after building work or pipe repairs
•New water systems that haven't been properly commissioned
•Seasonal re-opening of buildings with stagnant water systems
•Recurring contamination due to underlying system faults

Who Needs This

Chlorination is required after any significant work on a water system, including new installations, major repairs, or when contamination has been identified. Property managers dealing with failed legionella tests, landlords commissioning new water systems, and facilities teams responding to contamination incidents all require professional chlorination services.

Available Across London

Central London North London South London East London West London

Frequently Asked Questions

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