Do you actually need this?
Required by lawLegionella sampling or a legionella assessment: which one does the law require?
Water hygiene companies sell monthly monitoring and quarterly sampling to offices, shops and rented flats. The law requires an assessment and a control scheme. For most small premises, sampling is a cost with no legal basis. Here is the distinction.
What you were told: "You need quarterly legionella testing. It's a legal requirement."
What the law says: You must assess the risk from legionella in your water system and manage it. That's the Health and Safety at Work Act, the COSHH Regulations and Approved Code of Practice L8. The word "sampling" appears in HSE's guidance as something you do when the assessment says control is uncertain. It never appears as a duty.
Two different things
Identify the water system. Find where water could stagnate or sit between 20 and 45 degrees. Decide the controls. Hot water hot and cold water cold. Flush unused outlets and inspect any tank. Name the responsible person. Write it down and keep a log. That is the legal requirement. For a small simple system HSE says the person managing the premises can often do it.
Taking water samples for laboratory analysis. HSG274 Part 2 says routine sampling is not usually required for hot and cold water systems. It is indicated where temperatures cannot be maintained or the system is complex. It is indicated where occupants are vulnerable or there is a specific concern. Cooling towers and spa pools have their own regimes. For an office or a shop or a rented flat it is a decision and not a duty.
Where the money goes
The water hygiene contract. An assessment which is fine. Then monthly monitoring visits at £30 to £60 each to read two thermometers. Then quarterly sampling at £40 to £80 a sample. For a ten outlet office that is £600 to £1,500 a year. The guidance says you can do the checks yourself in ten minutes a month. It says you do not need the samples.
What to do instead
Get the assessment done. Use a professional if your system has stored water or tanks or showers or more than a handful of outlets. Then run the control scheme in house. Monthly temperatures at the sentinel outlets. Weekly flushing of anything unused. An annual look at the tank if you have one. Write it in a log. Review the assessment every two years or when something changes.
If the assessment recommends sampling and gives a reason then follow it. If the contract includes sampling by default then ask what in the assessment justifies it.
What you shouldn’t be sold
- A "legionella certificate". Doesn't exist.
- Routine sampling for low-risk premises. Not in L8, not in HSG274.
- Monthly monitoring visits for a small system. Two thermometers and a log.
- Tank cleaning on a schedule with no inspection finding. The tank is inspected; it's cleaned if it needs it.
- Chemical dosing for an ordinary building. Temperature is the primary control for hot and cold water systems.
Quick answers
- Is legionella testing a legal requirement?
- No. The legal requirement, under the Health and Safety at Work Act, COSHH and Approved Code of Practice L8, is to assess the risk and put controls in place. Sampling is only recommended by HSE where control is uncertain, where occupants are vulnerable, for complex systems, or during an outbreak investigation.
- Do I need a legionella certificate?
- No such document exists in law or HSE guidance. The risk assessment and the log of your monthly checks are the records. A letting agent or contractor asking for a certificate is asking for a form they sell.
General information, written for the person paying the bill. Opinion is labelled as opinion. Not legal advice. See our editorial standards.