Nitrate Water Test Results Guide

What this test measures

This test measures nitrate, which mostly reaches water from farming and fertiliser run-off. It’s one of the most important checks for wells and boreholes in rural areas — and in aquariums, rising nitrate is the classic sign it’s time for a water change.

The UK standard

The UK drinking water standard is 50 mg/l for nitrate. The limit exists mainly to protect bottle-fed babies, so it’s set with plenty of caution. Mains supplies are blended and treated to stay below it; private supplies in farming areas are where high readings usually appear.

Reading your strip

Dip a strip into your sample for two seconds, hold it level and wait 30 seconds. Match the nitrate pad against the colour chart on your instructions card and read off the closest band. Strips give you a clear range rather than a lab-precise number — exactly what you need for spotting problems and tracking changes over time.

What to do next

• Confirm it first. One strip is a snapshot — re-test with a fresh strip and a fresh sample before acting on a result.
• If a private supply reads high and a bottle-fed baby drinks the water, use an alternative source for feeds until an accredited lab has confirmed the level.
• If a reading on a mains supply stays above the standard after re-testing, contact your water supplier — they investigate quality concerns free of charge.
• On a private supply (well, borehole or spring), your local council’s environmental health team can arrange accredited lab testing.
• Thinking about a filter? Test before and after fitting it so you can see exactly what it changed.