Private Water Supplies - Case Study 2010/03

Spring supply to rented property – risk assessment and Notice

This water supply serves six dwellings; five of which are rented out and the sixth is occupied by the landlord. The source is a lowland shallow spring with no treatment. Spring water is pumped from a collection chamber to a relatively new storage tank serving all of the properties. A risk assessment was carried out which documented the following uncontrolled hazards:

  • wildlife and grazing of livestock around the source;
  • storage tanks not adequately protected due to deterioration of the structure;
  • septic tank discharge in the vicinity and uphill from the source;
  • no screens to prevent access by vermin;
  • no treatment;
  • an oil tank with no spillage bunding.

The risk assessment provided compelling evidence that the supply posed a potential danger to human health. Even though past testing had been satisfactory, it was clear that harmful material in the immediate local environment (fuel oil and faecal matter potentially containing pathogens) could gain direct access to the water supply due to the lack of safeguards and inadequate maintenance. Hazards were present from source to tap; in the catchment, from livestock and wildlife close to the source, direct ingress into water storage tanks and indirect seepage of oil or faecal matter through the ground into the source or by migration through plastic pipes or leaking joints. The lack of any treatment meant that the risk of water drawn from taps containing harmful contaminants was high.

The risk assessment enabled the local authority to issue a Regulation 18 Notice. The Notice documented the risk and restricted the supply (so that all users were made aware of how to safeguard their health by boiling water before use or using bottled water). The Notice required the owner to undertake maintenance so that the storage tank was sealed and water tight, to install effective treatment and put in place a written procedure for the maintenance and monitoring of the disinfection equipment. A timescale was set stating the time by which the owner should provide a proposal for permanent improvements to the supply to enable unrestricted use. There was no appeal by the owner in relation to this Notice.

This case study illustrates how the risk assessment approach in the new private water supply regulations can provide robust evidence as to whether or not a supply poses a risk to human health and warrants action. It should be noted that those renting the properties were ignorant of the risk and therefore unable to safeguard their health. Also, when the landlord was making improvements in respect of sufficiency (quantity) by means of installing a storage tank, he lacked the knowledge to understand the need for quality improvements, such as protection of the collection chamber or installation of treatment. This case therefore shows how putting reliance on very infrequent testing, under the previous 1991 regulations, resulted in a false sense of reassurance about the security of a supply. Testing on its own does not make water safe, whereas risk assessment empowers local authorities to encourage health-based action.