The challenge of keeping private water supply records up to date – a joint local authority and water company task
This case study concerns a farm premises comprising the farm and three other properties, one of which is a holiday let. The premises was connected to the mains and therefore recorded on the local water company customer records. In October, a sample was collected from one of the properties as part of the water company’s random sampling programme in the water supply zone. The sample contained E.coli and coliform bacteria. The water company immediately advised the occupiers to boil their water and commenced an investigation. From this it was established that while the farm premises was connected to the mains, all water used for both domestic and non-domestic purposes on the farm was derived from a spring. The farm owner indicated that the mains supply was being kept solely as a backup. The water company checked their meter readings and these confirmed that no mains water had been used in the past year.
The water company contacted the local authority and from this it was found that the private supply was not on their register. Although local authorities are required to keep and maintain records of all private water supplies in their area (Regulation 12) there is no statutory requirement for premises owners to notify the local authority of an intention to use a private supply for domestic purposes. Once aware of the situation, the local authority wrote to the owner of the supply informing them about the private supply regulations and to arrange to carry out a risk assessment and monitoring.
Meanwhile, the water company took investigatory samples and carried out a fittings inspection. This revealed that the mains water supply and the spring supply were separated by a stop valve which appeared to be secure, and posed no immediate risk of cross contamination. However, because the spring derived water is pumped to a reservoir on high ground that then gravity fed to the farmhouse and animal troughs, there was insufficient protection from contamination of the mains supply through the back pressure. This risk was verified by the investigational samples, which also contained E.coli and coliform bacteria. The company therefore served a fittings regulations Notice requiring a double stop valve to be installed. The owner took prompt action to install the double check valve, he also repaired the tank and put in treatment.
Figure 20: Spring collection chamber
Figure 21: Treatment arrangements showing filter and UV tube
In November, the local authority carried out its risk assessment and sampling. By this stage the supply configuration comprised the spring chamber from where water was pumped to a reservoir and then filtered and disinfected with UV before passing on to the properties. At the holiday let there was a point of use UV unit as a further barrier. The risk assessment revealed gaps in the record keeping and documentation regarding management of the supply. It also documented hazards in relation to the source and storage arrangements; however, it was concluded these risks were adequately mitigated by treatment. The sampling verified the risk assessment although it revealed that the pH was just below the standard.
This case study highlights how the maintenance of private supply records is a challenge that is shared jointly by water companies and local authorities. Like other case studies published by the Inspectorate, it points to the need for awareness-raising measures to be taken to ensure that premises owners know how to make their water supply arrangements safe. For its part, as mentioned in the earlier hospital case study, the Inspectorate has recommended to Defra that the private supply regulations are revised to include a duty on owners to notify the local authority.