How often should cold water storage tanks be cleaned?
Cold water storage tanks should be inspected annually and cleaned/disinfected as needed to control Legionella risk, per HSE ACoP L8 guidance.
Cold Water Tank Cleaning Frequency
Under HSE's ACoP L8 guidance, cold water storage tanks should be inspected at least annually, with cleaning and disinfection carried out whenever inspection reveals sediment, biofilm or contamination risk.
What's Involved
- Draining and physically cleaning the tank interior
- Disinfecting with an approved chlorine-based treatment
- Flushing the system thoroughly before refilling
- Checking tank covers, insulation and overflow pipework
This is particularly important for older London properties with loft-based tanks, and mandatory for managed/commercial buildings. RARE provides tank cleaning and Legionella prevention services across London.
Reviewed by RARE Plumbing London Engineering Team — Gas Safe registered engineers serving prime London since 2013.
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Tank Cleaning & Legionella Prevention
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