Lead testing is the one household water test where technique matters more than the laboratory. Lead enters water from the pipes and fittings it stands in, not from the source, so a sample drawn after the tap has been running measures almost nothing, and a sample drawn correctly measures what the household actually drinks.
Draw a first draw sample
Take the sample from a tap that has not been used for several hours, typically first thing in the morning, and draw it cold without running the tap first. That captures the water that has been standing in contact with pipework, solder and brass, which is precisely what a household drinks before anyone thinks about it. Do not remove or clean the aerator beforehand unless the laboratory's instructions say to, since scraping it changes what is in the first water through.
Sequential samples locate the source
One bottle tells you whether lead is present. Several bottles filled one after another trace it back through the plumbing: the first represents the tap and its fittings, later ones the internal pipework, and later still the service line to the street. That matters because the remedies differ enormously. A brass fitting is an afternoon's work; a lead service line is a shared job with the utility, and one that raises questions about partial replacement which are worth asking about before starting.
Consumer kits and what they can do
Test strips and colour based home kits do not resolve lead at the concentrations that matter, and a negative result from one should not be treated as reassurance. What a kit purchased for this purpose should contain is bottles from an accredited laboratory, written stagnation instructions, and a return label with a holding time. That is the meaningful product. Before buying, ask your utility: the EPA notes every community water system publishes an annual report, and many utilities run free or subsidised lead testing programmes.
What to do while you wait, and afterwards
Use cold water for drinking and cooking, since hot water dissolves lead more readily, and run a tap that has stood overnight before drinking from it. If the result shows lead, fit a filter certified specifically for lead reduction, confirmed in the certifier's own listing rather than on the packaging, and use it on cold water only. Replacing the source of the lead is the durable answer. Our water testing kit guide covers laboratories and what a full panel should include.
Questions people ask about lead testing kit for water
Should I run the tap before taking a lead sample?
No. A first draw sample from a tap that has stood several hours is what represents the water a household actually drinks.
Can a home test strip detect lead?
Not at the concentrations that matter. A negative result from a consumer strip is not reassurance.
What do sequential samples show?
Where the lead is coming from: the tap and its fittings, the internal pipework, or the service line to the street.
What should I do while waiting for results?
Use cold water for drinking and cooking, and run a tap that has stood overnight before drinking from it.