Every new or modified service must be thoroughly flushed with wholesome water to remove debris and organic matter that could foster biofilms.

It provides improved guidance on the control of Legionella and expanded details on calculating hot water storage capacity. Accessing the BS 8558 PDF

The standard is structured to provide specific "how-to" advice aligned with the parts of BS EN 806:

For larger systems or those where contamination is suspected, chemical disinfection (usually chlorination) is required. BS 8558 specifies contact times and residual chlorine levels (typically between 0.1 mg/L and 0.3 mg/L free chlorine after completion). 3. Hygiene and Legionella Control

The current version is , which superseded the 2011 edition.