Chlorination of Water Systems, Mains Water Pipework and Water Tanks

The cleaning, disinfection and chlorination of water systems is an essential activity that helps maintain good standards of water hygiene, especially in domestic water systems where microbial contamination can lead to serious problems. Cleaning and chlorination activities involve the addition of chlorine, a cost efficient but very effective disinfectant, to a water supply at a specific concentration, and for a specified period in order to clean and disinfect the water system, pipework and water tanks.

Chlorination of water systems

Chlorination of a water system in this way is tried-and-tested way of disinfecting water systems and their constituent parts, helping to kill dangerous waterborne pathogens including Pseudomonas and Legionella bacteria that may have contaminated the water system including its outlets, distribution pipework, water storage tanks etc.

Learn more about Legionella bacteria

Water treatment using chlorine has been used to clean and disinfect water systems successfully in the UK for over one hundred years and now forms an important disinfection process identified in a number of key standards including BS EN 806-5:2012, BS 8558:2011 and BS PD 855468:2015. These British Standards deal with the design, installation, testing, operation, cleaning, disinfection and maintenance of drinking water services inside buildings.

When is water chlorination required?

There are several circumstances when the chlorination of water systems, either new or existing, should be carried out and these include:

Contamination of water systems

If contamination of the water tanks or wider water systems is suspected, or water sampling and testing results indicate microbial contamination then full cleaning and chlorination of water systems should be carried out immediately. Full system chlorination should also be undertaken if an outbreak or suspected outbreak of Legionnaires’ disease is linked to the water system.

Legionella risk assessment recommends cleaning & chlorination

If a Legionella risk assessment report recommends chlorination of the water system should be carried out. This could include cleaning and chlorination of the water systems, distribution pipework, water tanks etc.

New, refurbished & modified water systems

Chlorination is required before a new or refurbished hot and cold water services installation is brought in to service, new components are added or the water system is substantially modified.

The procedures for flushing, disinfection and chlorination of water systems were originally dealt with under BS 8558, however they are now included in the 2015 British Standards document PD 855468.

It is also important to note that in the UK water utility companies impose strict standards for the cleaning and disinfection of mains water systems before they can be connected into their network.

Water system inactivity & stagnation

Cleaning, disinfection and chlorination of water systems should be carried out when the water services have not been used regularly, flushed or the water treatment control measures have been inactive for some time. This is because there is the potential for dangerous waterborne pathogens including Pseudomonas and Legionella bacteria to contaminate the water system and its components.

Additionally, situations that allow water to stagnate can also be problematic and these can include the use of over sized water tanks, deadends and deadlegs.

Expert water chlorination & disinfection solutions

Water Treatment Services is a leading independent UK water treatment, air, energy and environmental services company offering expert water management solutions including disinfection, cleaning and chlorination of water systems, pre-commission cleaning, boiler and cooling water treatment, energy efficiency and engineering support services.

With offices in London serving the South and South East England, Manchester (North West), Birmingham (Midlands), Bristol (South East England and Wales), Leeds (North and North East) and Glasgow (Scotland), supported by regional teams of specially trained engineers, site service specialists and technical experts we can offer water management solutions across the whole of the UK.