Legionella risk assessment cost calculator

Updated 16 August 2026

The cost of a legionella risk assessment depends on the water system, not on the building as a whole. A large building with a simple mains-fed plumbing arrangement costs less to assess than a small building with stored hot water, multiple calorifiers, and a cooling tower. The calculator below works off the four factors that drive most of the variation in quotes from Legionella Control Association registered contractors.

What drives the cost

The four factors above account for most of the variation in quotes between contractors. In order of impact:

• Cooling towers and evaporative condensers are the single biggest driver. Because they are notifiable, need a dedicated treatment regime, and require quarterly sampling to a UKAS-accredited laboratory, a site with even one tower will cost significantly more than a similar site without.
• Number of outlets drives the labour cost of the assessment itself. A proper survey checks every outlet at least once a year, and the more there are, the longer it takes.
• Stored hot water (calorifiers, hot water cylinders, storage tanks) adds complexity because each storage vessel is a potential colonisation site that needs its own inspection, temperature monitoring points, and periodic cleaning.
• Building type captures the regulatory overlay: care homes and hospitals are more expensive to assess because of CQC expectations and HTM 04-01 requirements, even for a similarly sized system.

What the price should include

A reasonable quote for a legionella risk assessment should cover:

• A site visit to survey the water system and create a schematic if one does not exist
• A written assessment following the ACOP L8 structure
• A written scheme of control setting out the monitoring regime
• Initial temperature readings at all outlets during the survey
• A formal report delivered within two weeks of the site visit

Sampling, ongoing monthly monitoring, cleaning, and remedial work are typically quoted separately as an annual service contract after the initial assessment is complete.

When to get multiple quotes

For any premises above the smallest commercial category, it is worth getting at least two quotes from different Legionella Control Association registered providers. Prices vary more than the service does, and a cheap quote from a non-registered provider often turns out to be significantly more expensive once the inadequacies become apparent at inspection.