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Water

How do I prevent legionella at home?

Short answer

Keep hot water at least 55 °C, preferably 60 °C, and cold water below 25 °C, preferably below 20 °C. Use every tap at least once a week.

Legionella thermometer: Cold water below 25 °C (ideally below 20 °C), hot water at least 55 °C (ideally 60 °C); in between is the danger zone where legionella grows.
Legionella thermometer — Cold water below 25 °C (ideally below 20 °C), hot water at least 55 °C (ideally 60 °C); in between is the danger zone where legionella grows. (The text inside the figure is in Dutch.)

Explanation

Legionella bacteria grow in lukewarm, stagnant water. Infection happens by breathing in tiny droplets, for example in the shower. The European Drinking Water Directive therefore asks for a risk-based approach for installations in buildings.

Rules of thumb

  • Hot water: at least 55 °C, ideally 60 °C. [SW-S32]
  • Cold water: below 25 °C, ideally below 20 °C. [SW-S32]
  • Use every tap and shower at least once a week. [SW-S32]
  • Have the water heater serviced every year. [SW-S32]

Pitfalls

  • Turning the water heater down to save energy increases the legionella risk. [SW-S32]
  • Empty garden hoses and pressure washers after use if they can heat above 25 °C in the sun. [SW-S32]

Search terms

These search terms are in Dutch; only terms that also find a topic in English are links.

legionella boiler warm water douche

Read also

General information, not personal advice. Check the source and reference date.

For health complaints: see your GP.

Sources

  1. SW-S32 Legionella bij je thuis — Departement Zorg (Vlaanderen) (Reference date 2026-09-27)
  2. SW-S36 Richtlijn (EU) 2020/2184 betreffende de kwaliteit van voor menselijke consumptie bestemd water — Europees Parlement en Raad (EUR-Lex) (Reference date 2026-09-27)

Reference date: 2026-09-27 · Translated with AI from the Dutch original.