- England uses three main private-supply categories under Regulations 8, 9 and 10; the correct category depends on how water is supplied, used and distributed.
- Regulation 9 covers supplies of 10 m³/day or more for domestic purposes and supplies used as part of a commercial or public activity, irrespective of volume.
- Risk assessment and monitoring are related but separate: sampling is a snapshot, while risk assessment considers the whole supply from source to tap.
- Local authorities carry out statutory functions; operators still need good day-to-day records, maintenance evidence and corrective-action history.
What counts as a private water supply?
A private supply is water supplied other than by a water undertaker or water supply licensee. In practice this can include water abstracted from a spring, borehole, well or surface source, and it can also include some arrangements where mains water is further distributed through a private network. The legal category matters because it affects risk assessment and monitoring duties.
The first operational job is therefore not to guess the category from the source type. A borehole can serve a private house, a holiday-let business or a large commercial site; those situations can fall into different regulatory categories even though the physical source looks similar. Keep a clear record of who uses the water, how it is used, how much is supplied and who controls each part of the system.
Regulation 8: private distribution systems
Regulation 8 concerns onward distribution of water from a water company where one or more consumers receive that water indirectly through a third party rather than directly as water-company customers. DWI revised its Regulation 8 guidance in 2024 and stresses that classification can require local-authority judgement; a shared or common supply pipe is not automatically a Regulation 8 arrangement.
For an operator, the private distribution network is the key evidence trail: pipework, tanks, fittings, points of use, maintenance and alterations. Keep a current schematic and record changes. For the narrower classification issues, see the Regulation 8 private distribution systems guide.
Regulation 9: large, commercial and public supplies
Regulation 9 applies where a private supply provides an average of 10 m³ or more per day for domestic purposes, or where water is supplied as part of a public or commercial activity. DWI gives examples including hotels, guest houses, restaurants, cafés, B&Bs, holiday accommodation, caravan sites and campsites. Commercial or public activity can bring a supply within Regulation 9 irrespective of volume.
Regulation 9 supplies are subject to Group A and Group B monitoring at frequencies set by the Regulations, principally according to the volume supplied, with the risk assessment also informing the monitoring programme. Keep sample dates, locations, laboratory reports, investigations and close-out actions together. See the dedicated Regulation 9 operator guide for the detailed commercial/public-use intent.
Regulation 10: other private supplies
Regulation 10 applies to private supplies outside Regulations 8 and 9. It includes smaller shared non-commercial supplies below 10 m³/day and a subset serving a single dwelling. Shared Regulation 10 supplies are risk assessed and monitored by the local authority at least every five years; DWI specifies E. coli, Enterococci, conductivity, pH and turbidity, plus other parameters indicated by the risk assessment.
Single-dwelling Regulation 10(3) supplies are different: routine regulatory risk assessment and monitoring are not required unless requested by the owner or occupier, although the local authority can act where it suspects a health risk. If use changes — for example to holiday accommodation or another commercial/public activity — classification must be reconsidered. See the Regulation 10 guide for the narrower small-supply intent.
Risk assessment: the source-to-tap view
Regulation 6 places risk assessment at the centre of the system. DWI describes a proactive, whole-system approach: identify hazards and control them through multiple barriers rather than relying only on a compliant sample at the tap. Local authorities must carry out or review risk assessments for qualifying private supplies at least every five years, with the single-dwelling exception described above unless an assessment is requested.
An operator cannot substitute their own checklist for the statutory assessment. They can, however, make the assessment more useful by maintaining a current schematic, source details, treatment specifications, service history, monitoring data, incidents, changes and evidence that corrective actions were completed.
Monitoring and sampling
Monitoring provides evidence about water quality at the time and place sampled; it is not a substitute for risk assessment. Regulation 9 uses Group A and Group B monitoring, with frequencies specified by the Regulations and linked to supply volume. Regulation 8 monitoring is determined from the risk assessment. Shared Regulation 10 supplies are normally monitored at least every five years for the core parameters described above, with extra parameters or frequency where the risk assessment requires it.
Avoid building a home-made statutory calendar from memory. Record the monitoring programme set or confirmed by the local authority, the exact sampling point, laboratory report and any follow-up. DWI expects samples to represent water as consumed, and risk-assessment findings can affect what else needs monitoring.
Record commissioning, source and treatment details, the risk assessment, monitoring requirements and any remedial work before use. This is particularly important for seasonal or long-closed premises where an old operating history does not establish that the reinstated supply is currently suitable.
Regulation 13 covers new private supplies and supplies brought back into use after at least 12 months of non-use, as well as previously abandoned or disused sources brought into domestic use. DWI says a qualifying supply should not be put into use until the local authority has completed the Regulation 6 risk assessment and determined the appropriate monitoring requirements.
New and reinstated supplies (Regulation 13)
When water quality or risk is a problem
If a local authority suspects a private supply is unwholesome, Regulation 16 requires investigation to establish the cause. Where the water constitutes a potential danger to human health, Regulation 15 requires consumers to be informed and advised, and Regulation 18 requires the local authority to serve a notice on the relevant person or persons to protect health and specify necessary action.
Not every failed parameter has the same enforcement route or health significance. Keep the laboratory result, authority advice, consumer communications, investigation, restrictions, remedial work and verification evidence together. See the Regulation 18 notices and action-record guide for the detailed notice workflow.
Fees and local-authority charges
Under Regulation 21, local authorities may recover the actual costs of specified activities such as risk assessment, sampling visits, investigations and authorisations. The 2018 amendments removed the old maximum amounts for England, so council charges can vary.
For budgeting, separate regulatory charges from laboratory costs, treatment servicing, consumables, electricity, contractor call-outs and capital replacements. That gives a more useful annual cost of operating the supply.
Records that make a private supply easier to manage
- Current source-to-tap schematic and site plan.
- Supply category and local-authority correspondence.
- Risk assessments, reviews and resulting actions.
- Sampling plan, sample records and laboratory reports.
- Treatment asset list, manuals, serial numbers and service history.
- Filter, lamp, chemical and consumable changes.
- Incidents, complaints, investigations and corrective actions.
- Changes to occupancy, business use, source, treatment, storage or distribution.
Good records do not prove that water is safe, but poor records make it much harder to demonstrate what was operated, maintained and investigated. Treat the record system as part of operational control, not as paperwork assembled only before an inspection.
Practical checklist
- Confirm the current supply category with the local authority rather than assuming it.
- Keep one current source-to-tap schematic.
- Record every sampling visit and attach the laboratory report.
- Log maintenance against the actual treatment asset.
- Create corrective actions when results, alarms or inspections identify a problem.
- Review classification whenever use, occupancy, distribution or treatment changes.
How the regulatory pieces fit together in practice
The easiest way to understand the Regulations is to separate four questions that are often mixed together. First, what type of supply is it? Second, what hazards exist from source to tap? Third, what monitoring programme applies? Fourth, what actions are needed when the risk assessment, monitoring or an incident identifies a problem? Classification, risk assessment, monitoring and enforcement are connected, but they are not the same process.
For an operator, the advantage of keeping those threads separate is clarity. The supply record can contain a classification note from the local authority, a current risk assessment, the sampling schedule and a corrective-action log. When one changes, the others can be reviewed without rewriting the whole history.
Common private-water-supply scenarios
A house supplied by its own spring or borehole
An owner-occupied single dwelling with no commercial use may sit within the Regulation 10 framework, but DWI explains that the single-dwelling provisions differ from shared Regulation 10 supplies. If the property is later rented, used as holiday accommodation or connected to additional premises, do not assume the old position still applies.
A holiday cottage or B&B
DWI lists holiday lets, B&Bs and guest houses as examples of commercial use under Regulation 9. The commercial-use test matters even when the daily volume is much lower than 10 m³. This is one of the most important practical points for rural property owners because a change of business model can change the regulatory position without changing the source at all.
A village or estate receiving mains water through private pipework
Where water from a water company is further distributed through a private network, Regulation 8 may apply. The water may have entered the private network meeting mains standards, yet storage tanks, old pipework, dead legs or fittings can introduce hazards downstream. A private distribution schematic is therefore central to the evidence.
What should happen when the supply changes?
Private supplies are rarely static for decades. Buildings are converted, pumps are replaced, new treatment is installed, businesses expand and properties change hands. Each material change should be recorded against the supply and considered against the existing classification, risk assessment and monitoring plan.
A disciplined change record should state what changed, why, who designed or installed it, when it was commissioned, which documents were updated and whether the local authority was informed. This is particularly important when a change affects the number of consumers, commercial/public use, source, treatment barriers, storage or distribution.
How to build a defensible operational history
The regulatory documents are only part of the evidence. Day-to-day operation creates a second layer: lamp changes, filter servicing, tank inspections, alarm events, contractor visits, complaints, power failures, sampling logistics and repairs. When these records are dated and linked to the correct supply or asset, they show how the system was actively managed between statutory visits.
That history is useful not only during inspection. It makes contractor handover faster, reduces dependence on one person’s memory, supports property transactions and helps identify recurring faults. A private water supply should be managed as a living system with a traceable history, not as a folder that is opened every few years.
Frequently asked questions
Do all private water supplies need the same testing?
No. Monitoring depends on the supply category, risk assessment and, for Regulation 9, factors including volume. Use the schedule set or confirmed by the local authority.
Is a holiday let normally Regulation 9?
DWI guidance lists holiday-let accommodation as an example of commercial use within Regulation 9. Confirm the specific arrangement with the local authority.
Does a good sample mean the supply is safe for years?
No. Sampling is a snapshot. DWI emphasises a source-to-tap risk-assessment and mitigation approach.
Can the council charge for private-water-supply work?
Yes. Regulation 21 allows recovery of actual costs for specified activities.
Does software replace the statutory risk assessment?
No. Software can organise evidence and actions, but the statutory role remains with the local authority or body it accepts as competent.
Keep the records behind this work together.
Use the free tools or start a 7-day trial to see how sampling, maintenance, actions and documents can sit in one source-to-tap record.
- DWI: Types of private supplies in England
- DWI: Regulation 6 risk assessment
- DWI: Regulation 7 monitoring
- DWI: Regulation 9 commercial and public supplies
- DWI: Regulation 10 other private supplies
- DWI: What sampling is required?
- DWI: Regulation 21 fees
- DWI: Regulation 8 revised guidance
- DWI: Regulation 13 new and reinstated supplies
- DWI: Regulation 15 consumer information
- DWI: Regulation 18 notices
- DWI: Private supply legislation
Regulatory guidance can change. Check the current DWI material and your local authority for the position applying to your supply.