Chlorinating Mains Water

Under the Water Supply (water fittings) Regulations 1999 (SI 1999, 1148), you will be required to disinfect your pipe work prior to connection. The disinfection must be carried out to ‘BS8558:2015’. This is to ensure there is no detriment to public health.

New supplies should be:

• Flushed and where possible swabbed to remove any contamination that has been introduced during installation.
• The water main will then be filled with a disinfecting solution (hypochlorite solution) to at least 50 ppm for at least an hour, ensuring that the strength is maintained throughout the disinfection process.
• After the disinfection period the water mains must then be flushed with good quality, potable water, until the chlorine residual measurements show that the chlorine concentration of the water leaving the mains is no higher than that generally prevailing in the distribution system.
• Bacteriological samples to be taken and sent to a UKAS accredited laboratory to ensure the disinfection has been successful.
• The water mains must be left in a sealed state to ensure the sterile condition.