Who is responsible for arranging drinking water quality testing?

Responsibility for drinking water quality testing is based on who controls the premises, the water system and the relevant legal duties. The accountable organisation must decide whether testing is needed, define the scope, appoint a competent provider where appropriate, review the findings and take action if results identify a risk.

The party responsible will vary according to the type of property and the way it is occupied. Typical arrangements include:

• Building owners: Owners of offices, factories, shops, schools, healthcare premises and other commercial buildings may need to establish how water quality is controlled throughout the site, particularly where the internal system is complex or water is stored, treated or distributed over a large area.
• Landlords: A landlord may retain responsibility for water quality within rented premises, especially where the landlord controls the incoming supply, storage tanks, shared services or maintenance arrangements. The tenancy agreement should clarify which duties are delegated to the tenant and which remain with the landlord.
• Employers and occupiers: An organisation using a building is responsible for the welfare of people affected by its activities and should understand the condition of the water supplied to staff, visitors, contractors or service users. This can apply even where the organisation does not own the property.
• Managing agents and facilities managers: These parties often arrange sampling, maintenance and contractor access on behalf of an owner or occupier. Their role should be defined in writing, including authority to commission tests and responsibility for escalating unsatisfactory results.
• Private water supply operators: Where drinking water comes from a private source rather than a public mains supply, additional duties may apply. The local authority can advise on the applicable regulatory requirements, sampling arrangements and any required remedial action.

The water company is generally responsible for the quality of water it supplies up to the point where it enters the premises. That does not automatically cover deterioration caused by the building's own pipework, tanks, outlets, treatment equipment or operating practices. The person controlling the premises therefore needs to consider what happens to the water after it enters the site.

Responsibility can become unclear where a building has several occupants or shared water services. A written responsibility matrix can identify who controls each part of the system, including incoming mains, tanks, calorifiers, point-of-use filters, vending equipment, outlets and sampling access. It should also state who receives laboratory reports, who decides whether a result is acceptable and who funds corrective work.

A responsible organisation does not necessarily need to collect samples itself. Sampling and laboratory analysis require suitable methods, correctly selected locations, appropriate containers, chain-of-custody records and interpretation against the relevant requirements. These activities can be delegated to a competent water hygiene provider, but the organisation commissioning the work should still check that the provider understands the building, the intended use of the water and the reason for testing.

Good governance normally involves the following process:

1. Identify the person or organisation with control of the premises and water system.
2. Review the building's water arrangements, including supply source, storage, treatment, occupancy and any higher-risk uses.
3. Decide which parameters require analysis and where samples should be taken.
4. Use a suitable laboratory and competent sampling personnel.
5. Record results with sample locations, dates, methods and relevant site conditions.
6. Have a nominated person review the report and assign actions where results are outside the required criteria.
7. Keep evidence of decisions, remedial work, follow-up samples and any changes to the testing programme.

Testing is only one part of the duty. Results should be considered alongside maintenance records, water temperature and turnover, changes to occupancy, complaints, alterations to pipework and any history of contamination. A single result may require investigation rather than an isolated pass-or-fail decision, while repeated adverse findings may indicate a wider problem with the system or its management.

Blue Fish Water Management Ltd can support the responsible organisation with risk-based sampling plans, UKAS-accredited water testing, compliance reviews and practical advice on follow-up actions. The duty holder remains responsible for making sure that testing is arranged, findings are understood and necessary controls are maintained.