Lead water testing means sending a sample from your own tap to a laboratory, because lead is picked up from service lines, solder and fixtures inside the property rather than from the source water. How you take the sample matters as much as which lab you use, since the same faucet can give very different results depending on how long the water sat in the pipe beforehand.
First draw and flushed samples answer different questions
A first-draw sample is taken after water has been standing in the plumbing for several hours, typically overnight, straight into the bottle with no running first. It shows the worst case, which is what you would drink if you filled a glass on waking. A flushed sample is taken after running the tap for a set period and reflects what the service line and the main are delivering once the stagnant water is gone. A big gap between the two points at your own fixtures and interior plumbing; similar high results in both point further upstream toward the service line. Labs that only offer one type are answering only half the question.
Choosing a laboratory and following its instructions exactly
Use a laboratory accredited for drinking water analysis, which most state environmental or health departments list publicly. The lab supplies its own bottles, preserved and prepared for metals, and the instructions that come with them are part of the test method: sample volume, whether to remove the aerator, how long to stagnate, how to store the bottle and how fast to return it. Deviating from any of that produces a number that is not comparable with the benchmark it is being judged against. Do not use a mail-order kit that arrives with a plain bottle and vague directions, since metals testing is unforgiving of contaminated sampleware.
What the utility report tells you and what it does not
Every community water system publishes an annual Consumer Confidence Report and the EPA maintains a finder for them. That report shows what the system found at its own compliance sampling sites and how it treats water to control corrosion. It is worth reading, and it is not a result for your house. Your service line material, your solder and your fixtures are outside the utility's sampling program. Households on private wells have less again: the EPA notes that private wells are not federally regulated under the Safe Drinking Water Act, so no report exists at all. Our local well testing page covers ordering a full panel where that applies.
Home test strips, and what they are good for
Instant lead strips and color-change kits are useful as a rough screen and nothing more. They are far less sensitive than laboratory methods, they are easy to misread, and a negative result on a strip should not be taken as an all clear at the levels that matter for lead. Where they earn their place is in checking whether a filter is doing something, or in screening several taps to decide which one is worth sending to a lab. Any result that concerns you, and any decision about replacing a service line or a fixture, should rest on a laboratory number.
Questions people ask about lead water testing
How much does lead testing cost?
It varies by laboratory and by whether lead is bundled into a wider metals panel. Ask about a panel rather than a single analyte, since arriving at a lab twice costs more than testing once.
Where in the house should I sample?
The tap you actually drink from, usually the kitchen cold tap. If you want to isolate a fixture, sample that fixture first-draw and then sample after a long flush.
Do I need to remove the faucet aerator before sampling?
Follow the lab's instructions. Some methods want it left in place because particulate lead trapped there is part of what you drink, others want it removed. The method decides, not the plumber.
How often should I retest?
After any plumbing work, after a service line replacement, after moving into an older house, and whenever a filter certified for lead reaches the end of its rated life.