Legionella Risk Assessment in Wandsworth

Legionella bacteria thrive in water temperatures between 20°C and 45°C, in stagnant water, and where there is biofilm, rust, scale, or sediment providing nutrients. Systems most at risk include those with dead legs (unused pipe runs), infrequently used outlets, storage tanks without lids, and water systems where the hot water is not stored at 60°C or above. The assessment identifies these risk factors in your specific property.

There is no fixed legal frequency, but the HSE recommends reviewing the assessment at least every two years, or sooner if there is a change to the water system, the building use changes, the results of monitoring suggest problems, or a case of Legionnaires' disease is linked to the building. For higher-risk buildings such as care homes and hotels, annual reviews are standard practice.

The assessor examines all hot and cold water systems, including boilers, cylinders, storage tanks, calorifiers, showers, taps, and any associated pipework. They check water temperatures at sentinel outlets (nearest and furthest from the heat source), look for dead legs or rarely used outlets, inspect tank lids and insulation, review the system schematic, and assess whether current controls are adequate to prevent bacterial growth.

No. A risk assessment is an inspection-based evaluation of the water system's design, condition, and management, resulting in a written report with control recommendations. Legionella testing (water sampling) involves taking water samples and sending them to a UKAS-accredited laboratory to detect the actual presence and concentration of Legionella bacteria. Testing may be recommended by the risk assessment but is a separate service.

Yes. The HSE can prosecute landlords who fail to assess and control the risk of Legionella under the Health and Safety at Work etc. Act 1974. Prosecution cases have resulted in significant fines and, in cases involving death or serious illness, custodial sentences. Even where no illness occurs, failure to have a documented risk assessment is itself a breach that can lead to enforcement action.

Wandsworth Council has historically taken a lighter-touch approach to licensing compared to some inner-London boroughs, but enforcement activity has increased in recent years. The borough's large stock of period conversions means that fire safety between flats (compartmentation, fire doors, detection) is a recurring issue flagged in fire risk assessments. EPC compliance is also a focus for the large buy-to-let market. The general legal requirements for legionella risk assessment apply across England, but London Borough of Wandsworth may have additional conditions attached to property licences or local enforcement priorities that affect how the requirements are applied in practice.

Wandsworth is a large, relatively affluent South London borough with a strong buy-to-let market. Housing ranges from grand Victorian and Edwardian properties in Battersea and Balham (many subdivided into flats), inter-war semis and terraces in Tooting, and modern riverside developments along the Thames at Battersea. The area around Clapham Junction has a particularly high density of converted flats and HMOs. The borough also has pockets of social housing, including several large estates managed by housing associations. Common property types that require this service include Victorian and Edwardian houses converted into flats, inter-war terraces and semis, modern riverside developments, HMOs near Clapham Junction. The specific requirements depend on the property type, tenure, and how the building is used.