How to Organise Private Water Supply Laboratory Results

1. Why organise laboratory results carefully?

A water test is evidence about a particular sample, collected at a particular place and time. It is not a permanent certificate for the whole supply. Good organisation preserves the context needed to understand what was sampled, why it was sampled, what the laboratory reported and what happened next.

That matters when several reports build up over years, when a supply has more than one sampling point, when treatment changes, or when an abnormal result triggers an investigation. A useful record lets you move from the original report to the affected supply, sampling location, investigation, corrective action and follow-up evidence without guessing.

2. Regulation 14: whose statutory record is it?

In England, Regulation 14 of the Private Water Supplies Regulations requires the local authority to maintain a record of every private water supply in its area. DWI says those local-authority records must be kept for a minimum of 30 years. That is not the same as a blanket requirement for the owner or operator to retain every invoice, note or laboratory PDF for 30 years.

Schedule 4 information recorded by the authority includes the monitoring programme and, for sampling and analysis, the date, result, location and reason for taking the sample. The reason may include routine Group A or Group B monitoring, monitoring arising from the risk assessment, investigation of a failure, an owner/occupier request, a complaint or an operational incident. The authority also records investigation outcomes, relevant notices, agreed actions and significant changes.

3. What owners and relevant persons should keep

There is no need to invent a duplicate regulatory database. The operator's priority is to preserve the evidence that makes each result usable. As a practical minimum, keep the original laboratory report, correspondence that explains any outcome or required action, and a clear operational index that connects the sample to the correct supply and sampling point.

• Original laboratory report or certificate in its original form.
• Sample date and sampling point/location.
• Reason for the sample: routine, Group A, Group B, risk-assessment monitoring, investigation, complaint or other operational reason.
• Laboratory and report/reference number.
• Any parameters identified as requiring action, using the wording and units on the report.
• Local-authority or laboratory communications that explain the reported outcome.
• Investigation, corrective-action and follow-up sample references where applicable.
• Relevant treatment, maintenance or change records that may explain the result.

Do not copy a value into a spreadsheet and then discard the report. Analytical reports can contain units, reporting limits, qualifiers, methods, accreditation scope and sample-identification information that a summary field cannot reproduce safely.

4. What to record for each sample

If you manage several supplies or sampling points, use consistent names. “Kitchen tap - Cottage 2” is more useful than “tap”; “post-UV outlet” is different from a consumer point downstream of a long distribution branch. Consistency makes trends and investigations easier to follow.

5. Original report versus workspace summary

The original accredited laboratory report is the primary analytical document. A workspace summary is valuable because it makes the result searchable and connects it to operational work, but it is deliberately a smaller record. Treat the two as complementary: original report for analytical detail; workspace entry for workflow and chronology.

This is particularly important if a result is later questioned. The original report may contain analytical qualifiers, detection/reporting limits, sample receipt information or method details that were never intended to be manually retyped into an operational dashboard.

6. Group A, Group B and sample reason

For Regulation 9 supplies, the local authority must carry out Group A and Group B monitoring at the frequencies specified by the Regulations and supply volume, together with additional monitoring shown necessary by the risk assessment. The purpose of the two groups differs, and each individual parameter should be recorded under the reason for which it was monitored.

DWI's current guidance makes an important administrative point: one physical water sample can be analysed for a combination of Group A and Group B parameters, but for reporting purposes each parameter still needs the correct monitoring reason. That is why recording only “annual sample” is often too vague.

Operational or private samples taken outside the statutory monitoring programme should also be labelled honestly. Do not turn a private check into “Group A compliance” merely because some of the same parameters were analysed.

7. Sampling points and multi-property supplies

Regulation 12 requires regulatory samples to represent water where it is consumed. DWI says this is usually a suitable point of use such as a kitchen tap, but the correct location depends on the supply. On a multi-property supply, the local authority does not normally need to sample every building on every visit.

The chosen point should represent the water consumed and the risks identified. Where there are several buildings, DWI notes that locations may sometimes be alternated over time. Additional points can be justified where distribution hazards, complaints, separate treatment devices or an investigation require them.

8. Failed results, investigation and repeat sampling

A result outside a prescribed standard or indicator value is not something to close simply because a later sample is satisfactory. DWI says a breach must be followed by a timely Regulation 16 investigation to establish the cause. Repeat testing may be part of that investigation, but resampling alone is not an investigation.

Your record should therefore preserve the chain: original result → who was informed → investigation → immediate controls/advice → cause → corrective work → follow-up sampling → outcome. If the issue is potentially dangerous to health, use the specific local-authority/public-health advice provided for that incident rather than applying a generic boil-water or do-not-drink rule yourself.

The same principle applies to indicator parameters. A value may require investigation even where it is not itself a direct health-based parameter, because the objective is to understand the cause and whether the supply controls are adequate.

9. Using trends without over-interpreting them

Historic results can reveal recurring seasonal changes, deteriorating treatment performance or patterns following rainfall, but trends only make sense when you compare like with like. A source sample, post-treatment sample and consumer-tap sample are not interchangeable. Nor is a result taken during an investigation automatically comparable with a routine compliance sample.

Record treatment changes, source changes, major maintenance and sampling-point changes alongside the result history. A run of satisfactory results is useful evidence, but it does not guarantee present-day safety and does not replace risk assessment or current monitoring.

10. Link results to actions and changes

A laboratory result is most useful when it sits in the wider operating record. If a result leads to service work, create or link the relevant corrective action. If treatment or distribution is materially altered, record the change in the change-management record. If the result exposes a new or changed hazard, the local authority's Regulation 6 risk assessment may need review.

Likewise, treatment servicing belongs in maintenance records, the original PDF belongs in the document store, and the supply layout belongs in the schematic. That separation keeps the evidence clear without duplicating every detail in every record.

11. Using the Monitoring workspace

Private Water Supply Manager's Monitoring workspace is deliberately an operational summary, not a laboratory interpretation engine. A real sample record stores the supply, sample date, monitoring/reason, sample point, laboratory, laboratory/authority reference, reported outcome, any parameters requiring action and notes.

The outcome choices are “Awaiting result”, “Reported satisfactory” and “Action required”. They record the outcome reported to you; the software does not calculate compliance from numbers. When “Action required” is saved, the current workspace automatically creates a linked review action so the result is not left without follow-up.

12. Documents, evidence packs and export

Use the Documents area for the original laboratory report. The Evidence Pack then includes the monitoring summary and a document index so a reviewer can see what evidence exists. The structured JSON export also includes the monitoring records and document metadata, but uploaded file binaries are intentionally not embedded in that JSON file.

This is why the safest workflow is to keep original reports as documents and use the Monitoring record as the searchable index. See the Evidence Pack guide for the wider record set and the sampling records guide for planning and field-record context.

13. England and the other UK nations

This guide uses the England Private Water Supplies Regulations and England regulation numbers. Wales, Scotland and Northern Ireland have separate private-water-supply legislation and administrative arrangements. Do not copy England's Regulation 7, 12, 14 or 16 numbering into records for another UK nation without checking the applicable regime.

14. Frequently asked questions