Electric showers, under-sink water heaters and instant hot water taps are common in offices, clubs, shops and small workplaces. They are convenient because they heat water close to where it is used. They are often seen as low risk for legionella, and many are, but they still need to be included in your legionella risk assessment and looked after properly.
Why they can still be a risk
- Lukewarm water. Many electric showers heat cold mains water to a comfortable temperature, which is also a temperature where bacteria can grow if water sits in the unit or hose.
- Low or irregular use. A staff shower used once a week, or a heater in a rarely used kitchen, may hold stagnant water.
- Showerheads and hoses. Scale and biofilm build up in heads and flexible hoses. See our guide to cleaning and descaling shower heads.
- Storage heaters. Small under-sink units that store water may not reach a high enough temperature, or may be set low to save energy. Our post on energy saving and hot water temperatures explains the balance.
- Cold feed. The cold supply to the unit may come from a tank, so the condition of that tank matters too.
Practical steps
- List them. Make sure every electric shower and point-of-use heater is identified in your legionella risk assessment.
- Clean and descale showerheads and hoses regularly. Quarterly is a common frequency, more often in hard water areas, but your risk assessment should set it.
- Flush little-used units. Run showers and taps that are not used regularly, typically weekly, to keep water moving. Read more on dead legs and little-used outlets.
- Check storage temperatures. Where small heaters store water, make sure they are set and working as your risk assessment recommends.
- Replace worn parts. Hoses and heads that cannot be cleaned properly should be replaced.
- Record it. Log cleaning, flushing and temperature checks in your legionella logbook.
- Think about vulnerable users. In settings with older people or people with health conditions, take extra care with showers.
These frequencies are typical practice, not legal rules.
Your duties
Section 19 of the Safety, Health and Welfare at Work Act 2005 requires employers to identify hazards and assess the risks to health. The HPSC National Guidelines for the Control of Legionellosis in Ireland (2009) set out practical guidance on controlling legionella in water systems, including showers.
We can help
A legionella risk assessment from Safer Solutions will cover every part of your hot and cold water system, from tanks to the smallest shower. We also provide legionella sampling, with samples analysed by an independent accredited laboratory. Call 086 275 9728, email info@safersolutions.ie or contact us online. See our legionella services.