Water Treatment and Water Hygiene Guides
Practical guides to chlorination certificates, Legionella risk assessments, water sampling and cold water storage tank maintenance, written by the team that carries out the work across London.
- 23 guides grouped by service: chlorination and certificates, Legionella and ACOP L8, water tanks and water hygiene
- Written around the published standards the work is judged against, including BS8558, ACOP L8 and HSG274
- Practical detail on what happens on site, what you receive at the end and what the timescales look like
Most water hygiene questions arrive in the same shape. Somebody has been asked for a certificate they have never heard of, or told an assessment is overdue, or handed a laboratory result they cannot read. The guides below answer those questions directly, so you can find the one that matches your situation instead of ringing round for it.
They are grouped by the service they belong to, and each one is written to be read on its own. Where a guide gives a temperature, an interval or a standard, it is setting out what the published guidance says. That is not the same as a judgement about your building, which needs somebody to look at the system itself.
Chlorination and certificates
Disinfection and certification of mains supplies, new pipework, potable water systems and stored water, plus the paperwork that proves the work was done properly.
Chlorination is what turns a newly installed or recently opened water system into one that can be signed off and put into use. These six guides cover the method, the laboratory sampling that sits behind it, and the certificate that Thames Water and other undertakers ask to see before a connection is approved. Our chlorination services page explains how we deliver the work itself.
Legionella and ACOP L8
Where the legal duty comes from, what a risk assessment covers, what testing tells you, and the points in the year when risk in a building climbs.
There is no single Act called the Legionella Regulations. The duty comes from the Health and Safety at Work etc. Act 1974 and the Control of Substances Hazardous to Health Regulations 2002, with practical advice in the HSE Approved Code of Practice L8, fourth edition 2013, and technical detail in HSG274. These eight guides turn that into what a duty holder actually has to do. Our Legionella services page covers assessment, testing, control and remedial work.
Water tanks and water hygiene
Stored water, cleaning and inspection schedules, disinfection, and the wider hygiene programmes that keep a building's water systems in order all year.
Stored cold water is where a lot of building problems begin. It warms up, it sits still, and it collects sediment and debris that give bacteria something to live on. These nine guides cover how tanks are cleaned, disinfected and inspected, when replacement becomes the sensible answer, and what a broader water hygiene programme includes. Our water tank services page explains the work we carry out.
Need help with a specific system
A guide can tell you what the standard says. It cannot tell you what your tank, your pipework or your risk assessment needs. Tell us the property, the system and the date any certificate is due, and contact our team for an answer on your own building. Call 020 4532 7773 or email info@londonwatertreatment.com.
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Chlorination Certificates: What They Are and When You Need One
What a chlorination certificate is, when one is legally required, and how the disinfection process works for water systems in London.
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Legionella Season Is Here: What Businesses Need to Do Now
Summer is the highest-risk period for Legionella development in commercial water systems. If your business has not reviewed its water safety arrangements recently, now is the time to…
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Spring Water Tank Cleaning in London: Why April Matters
As temperatures begin to rise in spring, the risk of Legionella development in cold water storage tanks increases. April is the ideal time to get ahead of the…
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Mains Chlorination in London: Thames Water Requirements
Before Thames Water will approve a new mains connection, the pipework needs to be chlorinated and certified. Here is what developers and project managers in London need to…
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What Is a Legionella Risk Assessment and Who Needs One
Legionella risk assessments are a legal requirement for many property owners and landlords, but there is still a lot of confusion about who needs one and what the…
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ACOP L8 Compliance in 2026: A Guide for Building Managers
A new year is the most practical time for building managers to review their water safety obligations. Here is what ACOP L8 compliance requires, what has not changed,…
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Water Tank Inspection Before the Christmas Shutdown
Most businesses think about security and heating when they close for Christmas. Water systems rarely make the list. Here is why a professional water tank inspection before the…
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Legionella risk assessments: a practical guide for landlords
Unsure how to do a Legionella risk assessment or how long it lasts? This guide breaks it down for landlords, duty holders, and property managers.
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Legionella risk assessments: who needs one and why it matters
Legionella risk assessments aren’t just for large buildings. Find out what they are, who’s legally responsible, and how to stay compliant.
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Benefits of regular tank cleaning and hygiene audits
Regular tank cleaning and hygiene audits aren’t just routine—they’re essential. Discover how they protect water quality, ensure compliance, and reduce risks.
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