Guidance documents

Information note on Regulation 11 (Wales)

For a printable copy see: Regulation-11-Walesv3-final-1.pdf (

Regulation 11 (Other private supplies including supplies as part of a domestic tenancy)

Regulation 11 applies to private supplies that are intended for human consumption that do not fall within the scope of regulations 8, 9 or 10. These include:

  • Supplies to all premises that are rented to tenants as a long-term dwelling, where the water is intended for human consumption, and where the volume consumed for those purposes is <10m3 per day.
  • Supplies serving more than one premises (for example neighbouring privately owned cottages or workshops) from a single source via a common supply pipe (ie a shared supply), where the combined consumption from the properties served for domestic purposes is <10m3 per day.

If the volume consumed is 10m3 or more per day, irrespective of whether the supply is used as part of a domestic tenancy, then regulation 9 applies. If the supply is serving a single dwelling that is not being rented for accommodation and/or is not used as part of a commercial or public activity, then regulation 10 applies. Supplies to short term tenancy accommodation, such as a bed and breakfast premises or holiday lets, whether single dwellings or not, fall with the scope of regulation 9.

Risk assessment

Regulation 6 requires that local authorities must carry out a risk assessment for all private water supply in its area where the water is intended for human consumption. These must be reviewed and updated every five years. The exception is where a supply serves only a single dwelling that is not used as part of a commercial or public activity or a domestic tenancy (unless it is requested). Therefore regulation 6 is applicable to all regulation 11 supplies, including those to single dwellings where the water is consumed as part of a domestic tenancy.


Local authorities are required to monitor regulation 11 supplies at least every five years and more frequently if the risk assessment shows this to be necessary, for the following parameters:

• Escherichia coli (E. coli); Enterococci
• Conductivity; Hydrogen ion (pH value); and Turbidity

Any parameter in part 1 or 2 of schedule 1 identified in the risk assessment as being at risk of not complying with the concentrations or values in those parts of that schedule.

Anything else identified in the risk assessment as a potential danger to human health.

PWS (Wales) Regulations 2017 v.3, February 2021