How to test your tap water for lead: a step-by-step guide for homeowners
11 min read · updated 2026-04-10
Certified labs, flushing procedures, first-draw vs running samples, and what the numbers on the report actually mean.
Should you bother?
If your utility's inventory shows your service line as lead, galvanized requiring replacement, or unknown, yes — a home test is the only way to put a number on what comes out of your tap. If your line is classified non-lead, the bigger risk is usually inside-the-house plumbing (brass fittings, old solder, faucets that haven't met the 2014 NSF/ANSI 61 low-lead standard), and a test still tells you something real.
A proper laboratory test costs $20–$50 and takes 5–10 minutes of your time. It is dramatically more accurate than a drugstore strip — strips detect free lead at far higher thresholds than the EPA action level and will miss most residential exposures.
Step 1: get a certified lab kit
Call your water utility first. Many utilities — including Chicago, NYC DEP, and DC Water — offer free or subsidized lead testing kits to customers. It's their cheapest way to satisfy LCRR sampling obligations and it's free to you.
If your utility doesn't have a program, get a kit from a lab certified by your state's drinking water program. EPA publishes a list of state certification officers at epa.gov/dwlabcert. Any lab certified for "lead in drinking water" will do. Nationally available options include LabCorp, Eurofins, and Pace Analytical — all have mail-in kits.
A proper kit ships you two small bottles (usually 250 mL each) labeled first draw and flushed, written instructions, and a prepaid return mailer. Do not use any other container. Lead adsorbs onto glass and metals; the kit bottles are nitric-acid-rinsed so the sample isn't contaminated.
Step 2: don't use the tap for 6 hours before sampling
This is the most-skipped instruction and the one that most changes results. Lead leaches from pipes into stationary water; the longer water sits, the more lead it picks up. A "first draw" sample after an overnight rest of 6–12 hours reveals the worst-case your plumbing produces. If you flush the line right before sampling, the number will look falsely low.
Plan to sample first thing in the morning, before showering, flushing the toilet, or doing laundry. Don't use even the kitchen tap for a drink of water; write a sticky note on the faucet the night before if you're forgetful.
Step 3: take the first-draw sample
Use the cold-water kitchen tap, not the bathroom. The kitchen is where most drinking and cooking water comes from, and it's typically the closest fixture to the main service line. Remove any aerator or filter first — they can trap lead particles and bias the sample.
Open the cold tap to a gentle stream and immediately fill the first draw bottle to the fill line. Cap it. Write your start time on the bottle.
Step 4: flush for 2 minutes, then take the flushed sample
Leave the tap running at the same flow rate for 2 full minutes. Then fill the flushed bottle to the fill line and cap it. This sample tells the lab what comes out of the service line itself, after the water sitting in your interior plumbing has cleared.
The comparison matters. If your first-draw result is 25 ppb and your flushed result is 4 ppb, your plumbing fixtures are the problem (replace taps; keep flushing). If both samples come back high, the service line is in play and you should escalate to the utility. If both are under 5 ppb, breathe.
Step 5: ship the kit within 24 hours
Lead can slowly stick to bottle walls over time. Drop the kit at the carrier the same day or the next morning. Most results come back within 1–3 weeks, either by email or through the lab's portal.
Reading the report
Lab reports use micrograms per liter (µg/L), which is identical to parts per billion (ppb). Here's what the numbers mean:
- < 5 ppb — below EPA's new trigger level. Low concern, though the health goal is zero.
- 5–10 ppb — above trigger, below action level. Flushing and a certified filter are reasonable precautions; consider inspecting plumbing.
- 10–15 ppb — at or above the LCRI action level (10 ppb as of October 2024). Use a NSF/ANSI 53 certified filter for all drinking water and cooking water immediately. Escalate with your utility.
- > 15 ppb — elevated. Stop drinking unfiltered tap water. Contact your water utility and local health department. If you have young children or a pregnant household member, request a blood lead test from your pediatrician or primary care doctor.
What a filter actually does
Certified point-of-use filters — look for NSF/ANSI 53 "lead reduction" on the label, not just 42 or 42/53 for "taste and odor" — remove 99%+ of lead when used correctly. Pitcher filters like Brita Longlast+, PUR Plus, and ZeroWater, along with many under-sink systems, carry the 53 certification.
Filters only work if the cartridge is changed on schedule. A spent cartridge can increase lead by releasing what it has adsorbed. Set a calendar reminder the day you install a new one.
Boiling water does not remove lead — it concentrates it by evaporating water without evaporating the metal.
Children under 6 and pregnancy
Lead's worst effects — neurodevelopmental — happen in young children and fetuses. The CDC's blood lead reference value is 3.5 µg/dL; above that level, public health action is recommended. A blood test is the only way to know. If your drinking water results are elevated and you have a child under 6 or a pregnant household member, ask your pediatrician or OB for a blood lead draw. It's a standard lab test and usually covered by insurance.
Next steps for residents
- Call your utility today and ask if they have a free testing kit program.
- If not, order a kit from any state-certified lab for $20–$50.
- Sample at the kitchen cold tap after a 6+ hour rest. Follow the two-bottle (first-draw + flushed) protocol.
- While you wait for results, run the cold tap for 30 seconds before drinking or cooking; that clears the worst of any sitting-water lead.
This article links to primary sources (EPA, CDC, utility portals) throughout. If you find a broken link or a factual error, please email [email protected].