Guidance documents

Information note on Regulation 6

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 (see Annex A). 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 take action to control those risks using 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 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, which is welcomed. The most up to date version of the Inspectorate’s 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 Inspectorate’s 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’s 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 appropriately trained, accredited and competent to perform risk assessments.2

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.

The primary objectives of a risk assessment in ensuring good drinking water supply practices are set out in annex A:

Each local authority is required to carry out a risk assessment of every private water supply every five years. The only exception is under regulations 6(2) and 10(3) 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(3)). Several factors determine the priority that the risk assessments should be arried 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.

Regulation 6(4) states that a risk assessment is to establish whether there is a risk of supplying water that would constitute a potential danger to human health. Local authorities must also use the risk assessment to establish whether there is a risk of non-compliance with any of the standards or indicator parameter values in schedule 1 to the Regulations.

In order to comply with regulation 6(5)(c), local authorities must take into account any data collected for the purposes of the monitoring conducted under the Water Framework Directive 2000/60/EC including that collected by the Environment Agency 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). 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. A review of a risk assessment should be undertaken whenever it considers the current risk assessment is inadequate or circumstances have changed significantly, such as the deterioration of raw water quality orinstallation of new treatment process.

A risk assessment must be completed as soon as is reasonably practicable once any new private water supply has been commissioned. (For further information see information note for regulation 13.)

Under regulation 6(6), local authorities must, within 12 months of carrying out a risk assessment, send a summary of the outcome of that assessment to the Drinking Water Inspectorate (acting on behalf of the Secretary of State). See information note for regulation 14.

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 (the 1999 Regulations). Enforcing the requirements of the 1999 Regulations is the duty of supplying water company. In such circumstances the local authority should contact the local water undertaker for assistance.

Breaches of the 1999 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 to achieve compliance will be with the water fittings regulations. The water company will be responsible for fittings enforcement and inspection, but the local authority is responsible for ensuring the risk has been mitigated with appropriate control measures. Please note that the water fittings regulations only apply to regulation 8 private water supplies.

It should be noted that monitoring requirements (analysis parameters and sampling frequency) for regulation 8 supplies should be based on the risk assessment. The regulations do not make any provision for Group A and Group B monitoring of regulation 8 supplies.

Temporary events

There is no regulatory 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 BS 8551 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 BS 8551.

It is the duty of water companies to regulate and enforce where necessary the Water Supply (Water Fittings) Regulations 1999 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.

Annex A – The principles of Risk Assessment.

The World Health Organisation (WHO) in its latest guidelines3 suggests:

  • Identify the risks in the catchment that affect, or could affect, the quality of the source of the private water supply and any control measures that are practical to reduce the risk (for example fencing to prevent animals contaminating surface water sources and protection to avoid surface water entering a borehole by means of a diversion ditch). In many cases, control measures in the catchment or at the source will not minimise the risks sufficiently.
  • For catchment risks associated with the application of organic and manmade fertilisers, local authorities should familiarise themselves with the requirements of The Reduction and Prevention of Agricultural Diffuse Pollution (England) Regulations 2018. These regulations set out minimum distances from surface and groundwater supplies whereby the application of organic and man-made fertilisers should be restricted. For further information refer to;
  • Identify the hazards that need to be controlled by treatment and, if appropriate treatment is not present (this may be the case for many supplies, particularly small supplies), install and maintain appropriate treatment processes to remove or reduce the concentrations of contaminants.
  • Identify the risks of contamination entering the distribution network (for example, through defective tanks and pipework) and take appropriate action to control those risks (inspections, repairs and maintenance).
  • Identify the risks of contamination within premises (for example from poor maintenance of pipes and fittings, particularly kitchen taps, and pick up of metals from older plumbing systems (for example, lead)) and take action to minimise these risks (often by providing advice to the owners/occupiers of the properties).
  • Establish the required control measures and the operational monitoring needed (for example operational sampling and analysis for key parameters against warning/alarm limits that are tighter than the standards in the Regulations and routine checks/inspections).
  • Establish standard operating protocols with appropriate records for treatment and distribution under normal circumstances and protocols for timely remedial action when the monitoring of control measures indicates an operational problem.
  • Identify any security risks associated with the source, treatment works and distribution network so that measures can be taken to avoid deliberate contamination.
  • Verify drinking water quality by establishing routine checks and inspections with appropriate records (for example, source protection is in place and operating effectively and that disinfection is operational) and by monitoring compliance with the standards and indicator parameter values in the Regulations.

Use of contractors

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 Private Water Supplies (England) (Amendment) 2018. 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’s 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 Regulations 2016 (as amended) v.4, February 2021