Guidance documents

Information note on Regulation 6 (Wales)

Regulation 6 (Requirement to carry out a risk assessment)

The key principles of the current Regulations are risk assessment and mitigation. This is a whole system approach for the lifetime of a private water supply and its operation. The Regulations have now moved beyond a simplistic compliance-based philosophy focussing at the end point of use. Risk assessment is a proactive approach to identify the risks (potential failures of standards and risks to human health) and to act to control those risks through a multi-barrier approach.

Point of use sampling is still an important requirement of the Regulations but in keeping with the risk assessment and mitigation principles, sampling and analysis alone cannot always provide assurance about the safety of a private water supply.

Each local authority must carry out a risk assessment of each private water supply system in its area1 at least every five years.

The Drinking Water Inspectorate (DWI) has developed set of risk assessment tools to help local authorities comply with their duties under regulation 6. Each has explanatory notes and a link to a training video on its use.

These tools are dynamic and have been updated from the feedback from users. The most up to date version of the Drinking Water Inspectorate risk assessment tool, must be used. If a local authority chooses to use an alternative methodology, to complete the risk assessment, they must ensure it complies with the standard BS:EN15975-2.

There are four versions of the Drinking Water Inspectorate risk assessment tool.

Risk assessors should select the most appropriate on a case by case basis:

  1. A tool which covers a comprehensive range of private water supply arrangements.
  2. A tool for common small supplies that employ simple treatment methods, known as the ‘Risk assessment Lite’ tool.
  3. A tool specifically for risk assessing supplies used exclusively for toilet flushing.
  4. A tool for supplies that originate from mains water and are classified as regulation 8.

A local authority may commission an external organisation or individuals to carry out the risk assessments on their behalf. They should use the Drinking Water Inspectorate tools for this purpose, on the proviso that these will not be used by any external organisation for any commercial gain outside the contract that has been agreed. The external persons must be able to demonstrate they are appropriately trained, accredited and competent to perform risk assessments2.

For supplies which have previously been risk assessed and were found to be low risk and well managed, any further assessments may be completed through correspondence with the relevant person(s) to confirm there have been no significant changes. In the absence of any updates, however, a site visit will be required.

Each local authority is required to carry out a risk assessment of every private water supply every five years. The only exceptions are under regulations 6(2) and 10(2) where water is a supplied to a single dwelling and is not used as part of a commercial or public activity. In this situation a risk assessment is not required, unless requested by the owner or occupier of the dwelling (regulation 6(3) and 10(2)).

Several factors determine the priority that the risk assessments should be carried out and these could include:

  • the number of people supplied;
  • the extent to which the water is used as part of a commercial or public activity;
  • the nature of the source (variable quality surface water, constant quality ground water);
  • the amount of treatment; and
  • the management and operation of the supply.

Where a risk assessment identifies an actual or potential risk to human health, or a risk of non-compliance with any of the standards or indicator parameter values in Schedule 1 to the Regulations, regulation 18(5) must be applied. The risk assessment must be used as part of the information to enable local authorities to consider whether it can exclude parameters from the monitoring requirements and include any other relevant parameters in addition to those specified in schedule 1, as informed by the risk assessment (see information note for regulation 7).

Local authorities must consider, as part of their risk assessments, any data collected for the purposes of the Water Framework Directive including that collected by Natural Resources Wales and by water companies as part of their raw water monitoring programmes.

If the water supplying the single dwelling is being used by the owner for a commercial activity or being provided to the public, the supply must be risk assessed under regulation 9 (see information note for regulation 9), excepting where this is as a part of a domestic tenancy agreement where regulation 11 applies.

Where water is a supplied to a single dwelling that is not used as part of a commercial or public activity or as part of a tenancy agreement, a risk assessment is not required, unless requested by the owner or occupier of the dwelling.

Where a private water supply serves premises in more than one local authority’s area, all authorities should agree a lead to prepare the risk assessment and share the outcome with the others (normally the local authority where most of the premises supplied are situated).

Local authorities should keep a full record of each risk assessment, including those carried out on its behalf. Review of risk assessments should be undertaken whenever it considers the current risk assessment is inadequate or circumstances have changed significantly for example, such as the deterioration of raw water quality or installation of new treatment process.

If any monitoring failures have occurred since the previous risk assessment then it should be updated to reflect the conclusion of the investigation carried out at the time, together with any action taken because of the investigation for example advice or notices. Evidence that remedial actions have been completed may be obtained through a site visit or other robust evidence such as photographs showing completed works or invoices from suppliers or installers. The type of evidence needed will depend on the type of work completed and the confidence that the local authority has in the relevant persons. In any case, the local authority should be satisfied that the work has been completed satisfactorily.

If a local authority becomes aware of a private supply that is to be, or is being used for the first time, a risk assessment must be completed as soon as is reasonably practicable (for further information see information note for regulation 15).

Local authorities should send a summary of the outcome of that assessment within 12 months to the Drinking Water Inspectorate (Acting on behalf of the Welsh Ministers. See Information Note for regulation 16).

Risk assessments of Regulation 8 supplies (See information note on regulation 8)

Water supplied to all regulation 8 supplies will originate from public supplies. The assets (pipes, tanks etc.) through which this water is supplied to consumers of regulation 8 supplies must be compliant with the Water Supply (Water Fittings) Regulations 1999. Enforcing the requirements of the 1999 Regulations is the duty of the supplying water company. In such circumstances the local authority should contact the local water undertaker for assistance.

Breaches of the Fittings Regulations should be recorded as hazards in the supply risk assessment and therefore contribute to the supply risk rating and development plan of that assessment. Where a potential danger to human health is identified, enforcement under regulation 18 will be required, but very often the mitigation required will be to achieve compliance with Fittings Regulations. The water company is responsible for Fittings Regulations enforcement and inspection; but the local authority is responsible for ensuring the risk has been mitigated with appropriate control measures. Please note that the fittings regulations only apply to regulation 8 supplies.

Monitoring requirements (analysis parameters and sampling frequency) for regulation 8 supplies should be based on the risk assessment. The regulations make no provision for Group A and B monitoring of regulation 8 supplies.

Temporary events

There is no requirement for local authorities to carry out a regulation 6 risk assessment on a supply for a temporary event that is fed from a public supply – either through pipes or via tankers, unless it is a regulation 8 supply, or supplied by other sources such as borehole, wells, springs etc.

However, as part of their general duties in protecting public health at all temporary events, local authorities should encourage that any supply intended for domestic purposes is provided in accordance with BS8551 and that those responsible apply a risk-based approach with respect to water supplies. Local authorities are advised to liaise with their colleagues in planning and licensing departments to ensure that any conditions of approval for temporary events stipulate requirements to adhere to BS8551.

It is the duty of water companies to regulate and enforce where necessary the 1999 Water Fittings Regulations at temporary events where there is a physical connection to a public mains supply. Local authorities should alert water companies to any pending temporary events in a timely manner.

Use of contractors

Notwithstanding the use of a third-party contractor, the ultimate responsibility for carrying out a risk assessment lies with the local authority as the regulator of private supplies under the Regulations.

If a contractor is used to undertake a risk assessment it is the responsibility of the local authority to specify that risk assessment must meet the requirements of European standard EN 15975-2 entitled “Security of Drinking Water Supply – Guidelines for Risk and Crisis Management – Risk Management.” This is a requirement of the Regulations, therefore the local authority must be satisfied that those requirements are met.

The local authority must decide on what regulatory action to take (or not to take) in reaction to the risk assessment or sample results, the third party cannot be the decision maker (the local authority must be able to prove that they considered the information to inform their decision).

1 Excluding those to single dwellings or on request from the supply owner.
2 Local authorities using external persons should conduct an audit of the risk assessments to be satisfied that they have been carried out competently and in accordance with the explanatory notes. An external organisation contracted to carry-out risk assessments on behalf of a local authority may be authorised by that local authority to use the Drinking Water Inspectorate tools for this purpose, on the proviso they will not be used by that external organisation for any commercial gain outside the contract that has been agreed.

PWS (Wales) Regulations 2017 v.5, February 2021