Specialty Testing Guide › Heavy Metals Testing
Lead gets into drinking water from the pipes and fixtures it passes through, not from the river or reservoir. In Pennsylvania the main risk is an old lead service line, the pipe that connects a house to the water main, along with lead solder and older brass faucets inside the home.
You cannot tell by looking or tasting. The way to know is to find out what your service line is made of, test your water, and, if there is a reason to, ask about a blood lead test. Each answers a different question.
Key takeaways
- Lead in tap water comes mostly from lead service lines, solder and brass fixtures in older homes.
- Philadelphia residents can look up their service line material online and ask the water department for a free water test.
- A water test finds the source, while a blood test shows how much lead is in your body.
- Cold water, flushing the tap and a filter certified for lead cut exposure while you sort out the pipes.
How lead ends up in tap water
Treated water usually leaves the plant without lead. It picks lead up on the way, when plumbing that contains lead corrodes. That happens more with water that sits in the pipes for hours, and with water that is more corrosive.
According to the US Environmental Protection Agency, lead service lines are more likely in older cities and in homes built before 1986.1 In homes without a lead service line, the most common problems are brass or chrome-plated brass faucets and plumbing joined with lead solder. Pennsylvania has a lot of both: older cities and towns, and a large share of homes built before 1986.
You cannot see, taste or smell lead dissolved in water. A clear, good-tasting glass of water tells you nothing about lead.
Lead service lines in Philadelphia
The city estimates that approximately 20,000 Philadelphia homes may have a lead water service line.2 The Philadelphia Water Department has built a public map of service line materials, where you can look up your address. Where the material is unknown, the city explains how to check yourself.
- Find the pipe. Locate the water meter, usually in the basement, and look at the pipe coming through the wall from outside.
- Scratch test. Gently scratch the pipe with a key or coin. Shiny silver could mean lead or steel.
- Magnet test. If a magnet sticks, the pipe is steel, not lead.
The city also lists ways to replace a lead line, including a zero-interest loan for homeowners and free replacement, with your permission, when the city replaces the water main on your street.
Elsewhere in Pennsylvania
Outside Philadelphia, your water utility is the place to start. Ask what its records show for your address, whether it offers water testing, and whether it has a replacement program.
Change is coming. In 2024 the EPA issued a final rule requiring water systems across the country to identify and replace lead pipes within 10 years.3 Replacement will take time, so knowing your own line now still matters.
If your home is on a private well, the utility rules do not apply to you, and testing is your responsibility. See arsenic and manganese in Pennsylvania private wells.
Water testing vs body testing
These two tests answer different questions, and people often mix them up.
| Question | Water test | Blood lead test |
|---|---|---|
| What it measures | Lead in a sample of your tap water | Lead in your blood right now |
| What it tells you | Whether your plumbing is a source | How much lead your body has absorbed recently, from any source |
| Who arranges it | Your water utility or a certified lab | Your clinician or your child's pediatrician |
| When it fits best | Lead line, older plumbing, or a new baby in the home | A known exposure, symptoms, or pregnancy planning in a high-risk home |
For most adults, the water test comes first. If water is the problem, fixing it is the treatment. A blood test is worth discussing when you have had a real exposure, such as years of drinking unfiltered water from a confirmed lead line, especially alongside other sources like old paint or work exposure.
Keep the risks in proportion. The Pennsylvania Department of Health notes that aging water infrastructure matters for lead poisoning, but more so for children.4 Infants who drink formula made with tap water, young children and pregnant people are the priority.
Lowering exposure now
While you work out your plumbing, a few steps reduce what you drink:
- Use cold water for drinking, cooking and baby formula. Boiling does not remove lead.
- Flush your pipes after water has sat for hours, by running the tap or doing a load of laundry or dishes. Ask your utility how long to run it.
- Use a filter certified to remove lead, and replace the cartridge on schedule.
Your next step
If you have reason to think lead has reached you, read adult blood lead levels explained to see what a result means, and blood vs urine vs hair metal testing for why blood is the test for lead. The heavy metals testing hub has the full series.
Frequently asked questions
Does a water filter remove lead?
Some do. Look for a filter certified to remove lead, install it as directed, change the cartridge on time, and do not run hot water through it.
Is bottled water necessary if I have a lead service line?
A certified filter or bottled water are both reasonable while you wait for replacement, especially for formula and for pregnant people. Ask your utility what it recommends.
Who owns the service line in Philadelphia?
Rules on ownership and replacement differ by town and can change. The Philadelphia Water Department can tell you what applies to your property and which replacement options you qualify for.
Should I get a blood test if my water had lead?
If young children or a pregnant person drank the water, talk to their doctors first. For other adults, it is reasonable to ask your clinician, especially if exposure lasted a long time or you have other lead sources.
Related reading
This article is for general education and is not medical advice. Decisions about testing and treatment should be made with your clinician. If you have severe symptoms, call 911. For a suspected poisoning, call Poison Control at 1-800-222-1222.
