Water quality testing: who to contact and what to ask
A useful test starts with a specific question. A hardness result and a drinking-water investigation answer different questions.
For a mains-water concern
Contact your drinking-water supplier first and describe the problem, when it started and which taps are affected. Ask for relevant results and whether sampling is appropriate. DWI advises this as the first step for concerns about mains tap water.
For a private supply
Contact your local authority for advice about testing a private water supply. Do not assume a neighbouring mains-water report describes a private well or borehole.
If you arrange independent testing
Discuss the concern with an accredited laboratory before collecting a sample. Ask which parameters, sampling method, bottles, transport and timing are needed, and whether those activities are covered by its accreditation. A sample collected incorrectly can give an unreliable result.
Keep the right records
Keep the laboratory report, sample date, sampling location, method and units together. Compare like-for-like results. An area average cannot establish the condition of plumbing in an individual property.
Check your published area information
Sources and review
Sources checked 6 September 2026. Prepared by WaterGrade.
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