Testing for lead is mostly a question of sampling technique, because lead almost never comes from the source. It leaches out of service lines, older solder and brass fixtures while water sits still in the pipe, so the sample you take decides the answer you get. A first-draw sample after the water has stood overnight tells you what your household actually drinks; a sample taken after a long flush tells you very little.
Understand where the lead is coming from
Lead in a household supply is a plumbing problem rather than a water source problem. The usual suspects are a lead service line between the main and the house, lead solder at copper joints in older work, and brass fittings and faucet bodies that legally contained some lead when they were made. That is why the level rises the longer water stands in contact with the metal, why the kitchen tap and the bathroom tap can give different answers, and why replacing one fixture can change the result. Knowing which of these you have narrows what to sample and what to do about a positive result.
Take the sample the way the lab expects
Use a certified laboratory kit rather than a colour strip, because lead matters at levels a strip cannot resolve. The standard protocol is a first-draw sample: no water used anywhere in the house for at least six hours, usually overnight, then fill the bottle from the cold tap you drink from without running it first and without removing the aerator. Do not use hot water for any sample. If you want to know whether the service line is the culprit, the lab can also take a sequential set: several bottles filled back to back, so the results trace the water from inside the house out toward the main.
What your utility report does and does not cover
Every community water system publishes an annual Consumer Confidence Report on what it detected, and the EPA maintains a finder for them, so start by reading yours. It will tell you about the treatment and about lead sampling done across the system, but it cannot tell you about your service line or your fixtures, which is exactly where household lead comes from. Private wells are not federally regulated under the Safe Drinking Water Act and produce no report at all, so a well owner has only their own laboratory results to work from. Our well water testing guide covers how to build a full panel around a lead sample.
Acting on a positive result
If lead comes back detectable, the interim measures are simple and worth starting the same day: use only cold water for drinking and cooking, run the tap until it turns noticeably colder before drawing water that has been standing, and clean the aerator screens, which trap loosened particles. For a lasting fix, a certified point-of-use filter on the kitchen tap is the fastest reliable barrier, and replacing the service line is the permanent one, which many utilities now share the cost of. Retest after any change, because a filter that is not certified specifically for lead reduction has not been shown to help.
Questions people ask about test for lead in water
Can a test strip detect lead in tap water?
Not reliably. Lead is a concern at levels far below what colour chemistry can resolve, so a certified laboratory analysis is the only result worth acting on.
Should I flush the tap before taking the sample?
No. For a first-draw lead sample you want the water that has been standing in the pipe overnight, because that is what shows how much the plumbing is contributing.
Does boiling water remove lead?
No. Boiling removes water as steam and leaves the lead behind, so the concentration in what is left rises slightly. Filtration or line replacement is the answer.
Do well owners need to test for lead?
Yes, if the house has older plumbing or brass fixtures, because the lead comes from the pipework rather than the aquifer, and no agency reports on a private well.