Frequently asked questions

A survey and written assessment of a building's water systems that identifies where legionella could grow, who could be exposed and what controls are needed.

It depends on the size and complexity of the building. Published UK prices range from around £70 for a small flat to several thousand pounds for large sites. See our cost guide or ask us for a fixed quote.

The duty holder: the employer, landlord or person in control of the premises. They can appoint a competent person or contractor to carry it out, but the legal duty stays with them.

Yes. Duty holders must assess the risk from legionella. For simple domestic properties the assessment can be proportionate and brief, but it still needs to happen and the findings should be recorded.

A typical rented flat or house takes under an hour on site. A small office or shop takes a few hours. Large sites such as schools, hotels or care homes can take a day or more, depending on the number of outlets and plant rooms.

Not usually. Routine water sampling is not a legal requirement for most domestic properties. The risk assessment decides whether sampling is needed, for example in healthcare settings, after remedial works or where temperatures cannot be controlled.

You receive a report with a remedial plan and a monitoring schedule. We can carry out the remedial works and ongoing monitoring for you, or train your own staff to do it.

Yes, if they are trained and competent. Many clients use a hybrid model where on-site staff carry out weekly flushing and we do the monthly temperature checks and annual inspections.

Out-of-range readings are flagged on the day with a recommended action, and we can return to investigate and put it right.

Tanks should be inspected at least annually and cleaned and disinfected when the inspection shows sediment, debris or contamination, rather than on a fixed timetable.

Usually only for a few hours. Where water must stay on, we can arrange temporary bypasses or work out of hours.

Yes. Where a tank is beyond economic repair or does not meet the Water Fittings Regulations, we can quote for a replacement WRAS-approved tank.

There is no law that names TMV servicing, but duty holders must control the risks of scalding and legionella, and HSG274 and manufacturers expect TMVs to be tested and maintained. In healthcare, HTM 04-01 sets the expectation.

TMV2 valves are certified for domestic use. TMV3 valves meet the more demanding NHS specification for healthcare and care settings.

Typically 20 to 40 minutes per valve, depending on access and condition.

No. Routine testing is not usually needed in rented homes. The risk assessment decides whether sampling is needed.

Laboratory analysis is usually charged per sample. Published UK prices start at around £40 to £60 per legionella sample plus VAT, plus the sampling visit.

Legionella culture usually takes around 10 days in the laboratory. Faster screening methods are available where speed matters.

We explain what the count means against HSG274 action levels and put together a response plan, which might include disinfection, remedial works and re-sampling.

New installations must be flushed, and disinfection is often required, particularly in larger buildings, healthcare premises or where water will not be used straight away.

Yes. We can work from any competent risk assessment and will flag anything that looks out of date.

No. There is no legal legionella certificate. A written risk assessment is the usual evidence that you have assessed the risk. See our certificate guide.

Published UK prices for a standard flat or house are typically £70 to £200 plus VAT, with HMOs and blocks costing more. See our cost guide.

Landlords must assess the risk. HSE does not insist on a certificate or a particular format, but you need to be able to show the risk has been assessed and controlled. A written record is the simplest way to prove it.

Testing is not normally required in domestic lets. Keeping hot water hot, cold water cold and water moving is what controls the risk.

No. A risk assessment looks at the water system itself. An audit looks at whether your management arrangements, records and actions meet the standard expected by ACoP L8.

Yes. The audit is independent and covers whoever produced the records.

Yes. Sessions can be run at your premises using your own water systems as examples, or remotely for awareness-level training.

Yes. Cooling towers and evaporative condensers must be notified to the local authority under the 1992 Regulations, and the authority told when they are no longer in use.

HSG274 Part 1 recommends legionella sampling at least quarterly, with more frequent sampling in some circumstances.

No. Infection happens when contaminated water droplets or spray are breathed in. Aspiration can occasionally be a route in vulnerable patients.

Legionella stops multiplying above about 50°C and dies quickly at 60°C and above. That is why hot water storage at 60°C is a key control.

There is no fixed legal interval. Review it when something changes, such as a new boiler or tank, alterations, a change of occupant type or a long void. Many letting agents review at each new tenancy or every two years.

Yes. Failing to assess and control legionella risk can lead to enforcement action and prosecution, particularly if a tenant becomes ill.

ACoP L8 is not law itself, but it has special legal status. Following it is usually enough to show compliance with the law on legionella.

At least five years.

Not on a fixed date. It stays valid only as long as it accurately reflects the system and the risks.

Legionella starts to multiply above about 20°C, so keeping cold water below that limits growth.

It is possible but not recommended. Chlorine handling, confined spaces and correct disinfection need training and the right equipment.

They are expected where vulnerable people could be scalded, such as care homes, healthcare, schools and nurseries, and in new and refurbished baths in homes under Building Regulations.

HSG274 treats outlets used less than once a week as little used. Anything that stands longer should be flushed before use.

Yes. A hot tub provided for paying guests is a commercial spa pool and must be risk assessed and managed.

Not usually. As with other domestic lets, temperature control and keeping water moving are the main controls. Sampling may be recommended in unusual cases, such as large stored systems that cannot reach temperature.

The landlord remains the duty holder. A letting or managing agent can carry out tasks on the landlord's behalf if this is agreed and they are competent.

A low count does not always mean a system is out of control, but it is a warning sign. HSG274 sets out when to resample, review controls and consider disinfection.

HSE or the local authority, depending on the type of premises. Local authorities also hold the register of notified cooling towers.

Yes, if they are competent and have been appointed with the authority to manage the programme.

Published UK prices for a standard rented flat or house are typically £70 to £200 plus VAT in 2026, with HMOs and blocks with shared tanks costing more.

Usually not. Most rented homes do not need sampling. Where it is needed, laboratory analysis is charged per sample.

Yes, if you are competent. HSE allows landlords to assess their own properties, but you need to understand the risks and record what you find.

No. There is no legal legionella certificate. Landlords must assess and control the risk, and a written risk assessment is the usual evidence.

Because there is no certificate, there is no validity period. A risk assessment should be reviewed when circumstances change, and many landlords review every two years or at each new tenancy.

An agent can make a written risk assessment a condition of managing your property. That is a contractual requirement, not a legal certificate.

Run each tap until the water reaches its normal hot or cold temperature. This is often two minutes or more. Your risk assessment may give a set time.

Little-used toilets should be flushed as part of the weekly routine, with the lid closed.

Automatic flushing devices can help, but they must be set up correctly, checked and recorded like any other control.

You can buy sample kits to post to a laboratory, but for most homes a thermometer and good flushing habits are more useful than a test.

Yes. Landlords must assess the risk, and Scottish Government repairing standard guidance expects a legionella risk assessment to be carried out.

No. As elsewhere in the UK, there is no legal certificate. A written risk assessment is the usual evidence.

Yes. The duty applies to all employers and people in control of premises. For a small, simple building the assessment can be short.

You still need to assess the risk. The legal requirement to write down the significant findings applies when you have five or more employees.

Standard split units do not spray water into the air, so they are not generally considered a legionella risk. Keep condensate trays clean and draining.

They can if poorly managed, which is why they must be notified to the local authority and treated, monitored and cleaned under HSG274 Part 1.

There is no single mandatory qualification. The assessor must be competent for the system, which usually means relevant training and experience.

A plumber can if they are competent in legionella risk assessment. Plumbing skills alone are not the same as risk assessment competence.