Read the Water Test Report Before You Choose a Provider: Units, Tests and Gaps

A test report decides which equipment is worth discussing, so check its units, its list of tests and its sample point before you compare any recommendation.

Most home water treatment decisions start with a report. A provider walks in with a test result, or asks you to hand over the one your utility publishes, and every recommendation that follows is only as good as the numbers on that page. Before you compare providers or equipment, spend a few minutes checking the report itself.

Check the units first

Hardness is the classic trap. Labs often report it in milligrams per liter as calcium carbonate, while many equipment specifications and sales sheets use grains per gallon. To convert, divide milligrams per liter by 17.1 to get grains per gallon. If the report and the salesperson quote different units, do the conversion yourself before accepting either number. The same applies to iron and manganese: confirm whether a figure is total or dissolved, because the treatment that fits dissolved iron is not always the one that fits particulate iron.

Confirm which tests were run

A short list of tests is not a full picture. Look for hardness, iron, manganese, pH, and any contaminant the provider cites as the reason for a specific product. If a recommendation depends on something that is not on the page, ask for that test or treat the recommendation as unverified. Also note where the water was sampled. Water taken from a utility main, an outdoor hose bib, or a kitchen faucet behind an older filter can differ from the water at the tap you actually use.

Ask where the sample came from

Ask who collected the sample, where it was taken, and which laboratory analyzed it. A page with no lab name, no collection point and no way to trace the results back to a source is a sales document, not a test. Use it for ideas about what to ask, not for sizing equipment.

Hold the report next to each proposal

Put the report beside every written proposal. The equipment named should address the problems shown on the page. If one quote treats iron, another ignores it, and the report shows iron, you have a question to put to both companies. Our review methodology page explains how this site weighs test results and recommendations, which may help you judge the claims you are given.