What tempering strategies keep fixtures safe from Legionella risk after ultra‑low temperature water‑heating?
To save energy, some set water heaters super low, but this can cause Legionella bacteria to grow. Here’s how to keep things safe:
- Faucet Valves: Mix cold water with the hot water at each faucet or shower to make sure the water is hot enough (over 120°F).
- Central Valves: Mix cold water at the water heater so the water stays hot enough to prevent bacteria growth, while still saving energy by storing water at a lower temp.
- Regular Hot Flushes: Heat water to 140°F every so often to kill bacteria.
- Shorten Pipes: Avoid long, unused pipes where water sits. Move water through the lines often.
- Check Temps: Keep storage temps low to save energy, but be sure the water from your tap is never in the danger zone (77–113°F).
The main thing is to store water at a low temp to save energy, but always mix it or move it around, so your tap water is hot enough to stop Legionella.
To keep fixtures safe from Legionella risk after ultra-low temperature water heating, maintain hot water temperatures above 60°C (140°F) in storage tanks and above 50°C (122°F) in circulating systems to effectively kill Legionella bacteria. For cold water systems, keep temperatures below 20°C (68°F) to prevent bacterial growth.
Use thermostatic mixing valves and maintain ≥60 °C in storage with ≥50 °C at outlets, flushing regularly to prevent Legionella growth.