How to test water quality at home: kits, labs and private supplies

Step 1: decide what you need to know

Different questions need different tests. Hardness affects limescale and appliance settings. Lead, bacteria and other drinking-water parameters need a specific test with the right sampling method. A general “water quality” score cannot answer all of these, and a hardness reading says nothing about safety.

How to test water hardness at home · Check your area’s published hardness

Step 2: for mains water, ask your supplier first

DWI says that if you have concerns about your tap water you should first contact your water supplier and explain the problem. Companies normally take a sample in response to a complaint, depending on its nature, and will give you the results of their routine testing free of charge on request. Describe what you notice, when it started and which taps are affected. Follow any current supplier advice for your address.

Where UK water quality data is published · How to read a water quality report

Step 3: what a home drinking water test kit can tell you

Water testing kits, strips and meters are sold for hardness, pH, chlorine, nitrate and a few other parameters. They can be useful for a quick check, such as setting an appliance, but read the limits before relying on one:

• Check exactly which parameters it measures, its range and its units.
• Colour strips usually give a band, not a precise figure; record the band rather than a single number.
• A TDS or conductivity meter measures dissolved solids in general, not hardness, lead or bacteria.
• Follow the kit’s sampling, timing and reading instructions exactly, and note the date, tap and result.
• A home result is not an accredited laboratory result. If it suggests a problem, contact your supplier or a laboratory.

Step 4: use an accredited laboratory for a reliable result

DWI directs people to the UKAS website to find an accredited laboratory. Before collecting a sample, ask the laboratory which parameters, bottles, sampling method, transport and timing you need, and whether those tests fall within its accreditation. For example, a first-draw sample (the first water out of the tap after it has stood, often overnight) and a flushed sample (taken after running the tap) answer different questions about lead from plumbing. A sample collected incorrectly can give a misleading result. Keep the report, sample date, location, method and units together.

Private wells, boreholes and springs

A private water supply is any supply not provided by a water company, whether from a well, borehole, spring, stream or lake. The rules differ from mains water:

• England and Wales: local authorities regulate private supplies under the Private Water Supplies Regulations 2016 (England) and 2017 (Wales), including risk assessment and monitoring. In England, a supply to a single private dwelling with no commercial or public use is excluded from monitoring unless the owner requests it. DWI supervises local authorities and publishes guidance.
• Scotland: local authorities regulate private supplies, supervised by the Drinking Water Quality Regulator for Scotland (DWQR).
• Northern Ireland: the Drinking Water Inspectorate within DAERA regulates registered private supplies; supplies to a single private dwelling are not required to be monitored.
• Everywhere: contact your local council’s environmental health team first. They can advise on testing, charges, and risk assessment for your supply.

Which areas WaterGrade covers

Do not use an area report as a test of a private supply

WaterGrade reports describe public supplies from published supplier data for a named supply area and period. They do not describe a private well or borehole, even one close to a mains supply area, and they cannot certify the plumbing in an individual property. For the published mains information near you, use the postcode checker below.

Hard water areas in the UK · Water quality in London · Water quality in Birmingham · Water quality in Leeds

Related questions

• How to test water hardness at home
• How to read a UK tap-water quality report
• Cloudy tap water: what to check