Legionella risk assessment for hotels and resorts
A resort has a lot of water system to control: hundreds of showers, long hot-water loops, spa pools, fountains, cooling towers, wings that close for the monsoon, and guests who fly home before the symptoms start. Thailand's recorded cases are almost entirely foreign visitors, and most of them stayed in Phuket, Samui, Krabi, Bangkok or Pattaya.
Who is checking, and what they expect
Tour operators
TUI's accommodation contract requires every hotelier to "implement and maintain a water safety management system that ensures ... that it is free from contamination such as legionella bacteria". Its audit checklist asks for a documented prevention plan based on the European 15-point plan, seasonal clean-and-disinfect records, Legionella testing records, temperature records with calibrated thermometers, weekly flushing of unoccupied rooms and a trained person responsible for water safety. SGS carries out the audits. A failed audit can be a material breach of contract.
The Thai authorities
The Department of Health guideline expects a water management plan, a responsible officer, hot water generated above 60 °C and above 50 °C at the tap, free chlorine of at least 0.2 mg/L checked daily and six-monthly sampling. The Department of Medical Sciences certifies hotels under the 3C Clean Hotel programme and the Department of Health under GREEN Health Hotel. On 18 September 2026 Legionnaires' disease was approved for the national list of diseases under surveillance.
European surveillance
When a European guest is diagnosed after a stay, the case goes to the ELDSNet network, then through WHO to Thailand's Department of Disease Control, which visits the hotel within days. Two cases at one hotel within two years is a cluster; tour operators are told about clusters even though hotel names are never published. Europe asks for a two-week report (was a site risk assessment done, was a water management plan in place) and a six-week report (what was found, what was done).
What we do for a resort
- A risk assessment of every system, including spa pools, fountains, misting systems and the villas on the edge of the site
- A written scheme mapped to the 15-point plan, the ABTA guide and the Thai guideline, so one document answers all three
- Logbooks and check sheets in Thai and English for the engineering and housekeeping teams
- Training for the responsible person, with a certificate for the audit file
- The low-season closure and reopening procedure, by wing
- Independent sampling at TEST TECH (ISO 11731:2017), IMC Thai (AS 3896:2017) or a Department of Medical Sciences Regional Medical Sciences Center (CDC-based method), separate from the chemical contractor
- Audit preparation, and an incident response if a result or a notification arrives
When a resort needs this
- Before a new opening, when the brand or operator asks for a water management plan
- Before the winter season, after wings have been closed since May
- When an auditor marks the Legionella section as a priority finding
- After a positive sample from the contractor's routine test
- After a guest notification
We cover Phuket, Khao Lak, Krabi, Koh Samui, Pattaya, Hua Hin, Bangkok and the rest of Thailand. Travel from Bangkok is quoted up front.
Sources:TUI Addendum;TUI Full Operational Assessment;Bureau of Environmental Health guideline;Division of Epidemiology 2025;Bangkok Biz News, 18 September 2026;ECDC Form A;ECDC Form B.
Get a quote for your property
Tell us the property type, where it is, how many rooms and whether it has cooling towers. We reply with a price and the earliest survey date, usually the same working day.
Had a positive result, or a notification about a guest?
What you do and record in the first 24 hours is what investigators and tour operators will read later. Get in touch now for advice on disinfection, independent resampling and the evidence they will ask for.