Using a Private Water Supply

Relevant Person

The relevant person is defined in Section 80 (7) of the Water Industry Act 1991 as;

  • The owner or occupier of the premises supplied; and
  • The owner or occupier of the premises where the source of the supply is situated even if the source lies outside the local authority's area; and
  • Any other person who exercises powers of management or control in relation to that source

These definitions are intended to provide sufficient flexibility to take account of the wide variety of arrangements by which people access private water supplies and therefore it is likely that there may be more than one relevant person for a single supply.

The implications to the relevant person(s) are dependent on the type of private supply (PDF 90KB) used.

Ensuring the supply complies with the Regulations

The local authority has a duty under the Regulations to conduct a risk assessment of all private water supplies within its area (except for single domestic dwellings). The main purpose of the risk assessment is to identify any hazards that present a contamination risks to the supply and ensure appropriate measures are put in place to mitigate against these risks.

If the risk assessment identifies any actions or improvement work that is required to mitigate risks to the supply then the local authority will provide an action plan to the relevant person(s) to facilitate the improvements outlined within the risk assessment to an appropriate risk based deadline. The Inspectorate has produced guidance that outlines some key measures that relevant persons can undertake to protect the supply (PDF 78KB) against the main forms of contamination.

In the event that the relevant person(s) fails to secure the necessary improvement work in accordance with the action plan provided, local authorities are duty bound to use enforcement powers, where applicable, to ensure the supply meets the requirements of the Regulations. Furthermore where a local authority is unable to obtain information from relevant persons, or is unable to gain access to premises of relevant persons in order to undertake its regulatory duties, it is afforded additional powers to act under sections 84 and 85 of The Water Industry Act 1991, as it sees fit.

The risk assessment must be conducted by a competent person, which is the local authority or someone approved as competent by the local authority.

Local Authorities can charge the relevant person(s) in order to cover their costs for conducting their duties. In Wales, maximum charges for each service are outlined in Schedule 6 of the Regulations. In both England and Wales, the charge should only cover the reasonable cost of conducting each service. Details of charges for these services should be available on local authority’s websites, or they can be otained by contacting the local authority directly.

However to save time and potentially costs, the relevant person(s) can collate relevant information (PDF 433KB) regarding the supply and provide this information to the local authority in advance of their visit. Dependent on the type of supply a local authority may ask for this pre-assessment to be completed as a matter of course.

Sampling and Analysis (Monitoring)

Analysing samples of water from the point of consumption on a supply can be useful to verify the presence of actual or potential contaminants, or to determine whether any treatment systems are operating in accordance with the manufacturer's instructions. It can also verify whether or not the measures in place to control risks are effective and suitable to ensure the water is safe to consume. However, the assessment of water quality from a sample is limited to the parameters being tested at the time.  Furthermore water quality may be variable over time for a number of reasons (e.g. seasonal changes) and consequently a sample will only be representative of the quality of the water in the snapshot of time it was taken. The monitoring of a supply is nevertheless an important and necessary regulatory requirement (excluding supplies to untenanted single dwellings), the results of which should be used in conjunction with risk assessments to judge the safety of a supply.

The frequency of sampling a private water supply will be dependent on the supply type (e.g. Regulation 8,9 and 10, and in Wales 11).

Sufficiency of the Supply

The relevant person(s) is responsible for ensuring the sufficiency of the supply at all times and therefore should have plans in place to deal with insufficiency, drought (PDF 107KB) or contamination. Having a contingency plan in place to will reduce the time it will take to respond to and manage any issue and it may help reduce costs. These plans should include procedures for the provision of an alternative supply to all consumers of the supply during the period of insufficiency, or whilst any remedial action to mitigate contamination risk is being carried out..

These procedures should include as a minimum:

  • The total number of consumers supplied
  • Typical amounts of alternative water required for each consumer
  • The type of alternative water arrangements (e.g. provision of bottled water, bowsers or tankers)
  • Plans to cope with a long (e.g.a prolonged drought) and short (e.g. during minor repair work) duration of insufficiency
  • Communication arrangements during the period

The Water Industry Act 1991 gives local authorities, if required, the power to serve a Section 80 Notice on a relevant person(s) to take appropriate action to address actual or potential insufficiency.


Communication with Users

Person(s) exercising control over a private water supply, when necessary, should ensure that every user on the supply is made aware of any water quality or potential insufficiency issues associated with the supply (and must do so in accordance with any notice served by the local authority). In these instances they should use appropriate methods of communication to inform users, including those where any required interim restriction measures are required, for example, boiling the water before use, using bottled water only etc whilse longer term control measures are put in place.. Some local authorities will do this on behalf of the relevant person(s).


Page reviewed: 11 March 2019
Page modified: 11 March 2019

Drinking Water Inspectorate