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Built with researchers at Imperial College London

How it works

How do I test my tap water?

You can test your tap water at home in about five minutes. Order a kit and it arrives in one working day. Fill two bottles with the first water out of your tap, post them back free in the prepaid box, and get your results online within 3 working days of them reaching our lab.

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From £49, with free postage both ways

The WaterGraph test kit: a box and two sample bottles

From start to finish: four easy steps

  1. Order a test

    You can choose how many taps to test: 1, 2 or 3. Your kit arrives in one working day with a returnable prepaid box.

    The two sample bottles in a WaterGraph home water test kit

  2. Fill two bottles

    First thing in the morning, before anyone uses the tap, fill both bottles with the first water out of it, so we can see what's in your pipes. Fill until they're overflowing, then seal the lids very tightly. It takes about five minutes.

    Water running from a kitchen tap: the first water out of the tap is your sample

  3. Post them back

    Pack the bottles back in the box and post it straight away, so your sample is accurate. And before you worry about the postage: don't. That one's on us.

    WaterGraph kit boxes with their Royal Mail labels: the kit comes to you and goes back to our lab by post

  4. Results in 3 working days

    Within 3 working days of your sample reaching our lab, you get a summary of your results and a Care Plan, guiding you through any issues that might need fixing and how to fix them. Always in plain, jargon-free English.

    A WaterGraph water test report on a phone: the verdict, a Water Health Score of 87 out of 100, and the water supplier

What you get

  • Your Water Health Score. One number for your water, scored against UK limits and typical UK levels, with our method published.
  • Every reading in plain English. Each of the 8 key things, with its UK limit and what it means for your home.
  • A personalised Care Plan. Exactly how to improve your water's health, based on what you're interested in, and what not to waste money on.
See an example report
The Care Plan in a WaterGraph report, with Nitrate open: the reading set against the UK limit and the local average

Good to know

From us to you

Everything is done by post, anywhere in the UK: we send you a kit, you post your water sample back, and we test it in our lab. We don't test in person.

Test more than one tap

Each tap needs its own kit: choose 1, 2 or 3 taps on Test, Guard or Premium and everything arrives in one order. For example, compare the kitchen tap against the bathroom, or the same tap with and without your filter. Premium's PFAS (forever chemicals) test covers one tap.

Keep Guard

WaterGraph Guard, £59 a year. Two tests six months apart, plus alerts all year if something goes wrong on your water network.

About Guard

Test your tap

A lab test of your tap water, your Water Health Score and a Care Plan, posted UK-wide. From £49.

Get a Test