Private Water Supplies
Private water supplies need a different decision route from mains water because the source, treatment, storage and tap are part of the same risk picture. This page helps households, farms, holiday lets, rentals and shared rural supplies screen, understand and act without relying on taste, smell or one test alone.
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Source to tap: where problems can enter
For private supplies, the useful route is Source -> Treatment -> Storage -> Tap -> Result -> Next action. A borehole, well or spring can be affected by rainfall, land use, geology, treatment failure, tanks, pipework and sampling technique. Testing should start with the risks most likely to change the decision you need to make.
- Source: well, borehole, spring, surface influence, heavy rain, flooding or nearby land use
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- Treatment: filters, UV, chlorination or maintenance gaps
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- Storage: tanks, lids, sediment, stagnation and shared supply arrangements
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- Tap: kitchen tap sampling, pipework and point-of-use changes
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- Result: screen first, then interpret before deciding whether confirmation is needed
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- Next action: retest, service treatment, contact the council or confirm with a lab
What to test first
Bacteria and E. coli are often the first safety-action checks because clear-looking private supply water can still be contaminated. A broader chemical screen is useful when the source, geology, pipework, treatment or history is unclear. Arsenic becomes more relevant where groundwater and geology make it a plausible concern.
- Test E. coli/bacteria after heavy rain, flooding, source disturbance, tank concerns or treatment failure
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- Use a broader Complete Kit when several issues may be present or the supply has not been reviewed recently
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- Consider arsenic where groundwater/geology or local history makes it relevant
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- Do not use taste, smell or clarity as proof that a private supply is safe
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- Follow sampling instructions carefully because poor sampling can mislead
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- Use council or lab routes where results affect guests, tenants, business use or treatment decisions
How to act on private supply results
A home screen can help you decide what to check next, but it is not a full private-water-supply risk assessment. Use the Result Interpretation Centre to understand what the result can and cannot tell you, then decide whether to retest, service treatment, contact the local council or arrange formal laboratory confirmation.
- Escalate quickly for positive E. coli, illness concerns, sewage-like odour or flooding context
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- Contact the local council where a private supply serves others or formal advice is needed
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- Use the map for local context, source protection and nearby community submissions only
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- Keep records of source conditions, treatment maintenance, sampling point and results
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- Retest after treatment changes or remedial work rather than assuming one result settles the issue