Three different questions need separate answers: Can it measure accurately? Can its wetted materials be used for this water? Is it accepted for this specific billing or regulated application?
Request the applicable certificate or listing for the exact make, model, size, configuration and use. A brochure stating “ISO,” “MID,” “ISI,” “CGWA compliant” or “approved” is not the complete evidence package.
For India, BIS publishes standards information and an order referencing IS779 domestic and IS2373 bulk water meters. Use these as verification starting points; confirm the current standard, amendments, licence scope and applicability to the offered product through official records. Do not treat this guide or an old catalogue as a definitive current compliance determination. BIS standards portal, BIS-published water meters order
Drinking-water component certification and lead-content certification are distinct from measuring accuracy. NSF maintains separate listings for NSF/ANSI/CAN61 drinking-water components and NSF/ANSI/CAN372 lead content. Verify the relevant listing rather than relying on a general logo. NSF certified-products directories
A serial-number calibration report, model/type approval, factory test report and material declaration are different documents. Specify which you need, the required test points and traceability, and who accepts them. For a utility, abstraction permit, fire-service or environmental-reporting project, match the actual project requirements before purchase.