Pressure testing, disinfecting and commissioning is required for private supply pipes and mains pipes before they are allowed to be connected to the public water supply. This is done for two main reasons: to ensure a safe standard of water quality for all, and to maintain an acceptable level of public health standard.

Testing and disinfecting should always be performed on pipes that are over 100 metres in length, as well as any pipes that have been compromised in any way. This is especially so if the pipes in question have suffered an ingress due to damage. This could be from flood water, for example, or of considerably more concern, from sewage perhaps. Any pipe that has been damaged and repaired, or even replaced, should be tested thoroughly to ensure the complete integrity and safety of the whole system.

Private supply pipes, or private water mains pipes, are normally classed as those pipes attached directly to a property. They usually remain within the boundary of the property and connect to the local authority infrastructure water mains pipe system through a boundary stop tap. These pipes are normally the responsibility of the individual customer of the local authority who receives water from the public mains supply.

Because private mains and supply pipes are not under the direct control of the local authority, it is essential that they thoroughly and properly undergo pressure testing, as well as disinfecting before being commissioned by the local authority and deemed as being suitable for inclusion in the overall water mains system.

Before any testing through pressure can commence, the pipes have to be properly cleaned of all debris and dirt that may be present. This is done by flushing at a high enough rate of flow to remove whatever sediment there may be. If the pipe is badly contaminated, it may require a mechanical means of cleaning to remove any stubborn sediment deposits.

Following the flushing procedure, the pipe should be dosed with a solution of chlorine at a strength of at least 50 milligrams per litre. The solution should be contained within the pipe for a minimum period of one hour for maximum effect. Further flushing should then take place to thoroughly clean out the pipe.

Pressure testing can then commence. The pipes should be tested at one and a half times the pipes’ pressure rating. Naturally, all safety procedures should be  properly observed, and the entire operation should only be performed by operators who are fully trained and experienced.