Guides and advice

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.

A commercial plant room with copper and blue plastic pipework running along the walls, an insulated cylinder to one side and a grey sectional cold water storage tank at the far end.

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.

An assessor in a hi-vis vest recording details on a tablet beside a large insulated hot water cylinder and a run of copper pipework.

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.