Specialty Testing Guide › Heavy Metals Testing
If your home runs on a private well, no agency checks your water for you. In Pennsylvania, testing a private well is the owner's job, and two metals worth knowing about are arsenic and manganese. Both occur naturally in rock and groundwater, and neither has a reliable taste or smell at levels that matter for health.
The answer to "am I exposed?" starts with a water test, not a body test. Once you know what is in your water, you can decide whether treatment, a different water source or a medical test makes sense.
Key takeaways
- Pennsylvania does not require private well owners to test, so many wells have never been checked for metals.
- Arsenic is common enough in Pennsylvania groundwater that a one-time test is worth doing for any drinking water well.
- Manganese often shows up as black staining, but it also has a health advisory level, with extra caution for infants.
- A certified lab test of your well water should come before any urine or blood test for these metals.
Private wells in Pennsylvania are your responsibility
More than one million homes in Pennsylvania are served by private water supplies such as wells, springs and cisterns.1 Public water systems must meet federal drinking water standards and test regularly. Private wells do not.
Penn State Extension puts it plainly: private water supply testing is the voluntary responsibility of the homeowner. The Pennsylvania Department of Environmental Protection does not regulate private wells, though it does keep a list of accredited labs. Penn State's general advice is to test every year for coliform bacteria and every three years for basics such as pH, with extra tests based on nearby land uses and anything you notice, like staining or a metallic taste.
Arsenic and manganese are not on that yearly list by default. You usually have to ask for them.
Arsenic: invisible and naturally occurring
The federal limit for arsenic in public drinking water is 10 micrograms per liter, also written as 10 parts per billion. Private wells are not held to it, but it is the sensible benchmark.
A US Geological Survey analysis of state well data found that nearly 8% of Pennsylvania groundwater samples had arsenic at or above that level.2 Most of it comes from the local geology. Less often, the source is mining or old orchards where arsenic pesticides were once used.
Long-term drinking water exposure is the main concern. Drinking or breathing low levels of inorganic arsenic for a long time can darken the skin, and swallowing it raises the risk of skin, liver, bladder and lung cancer.3 These effects build over years and rarely cause early symptoms, which is why testing the water matters more than watching for signs.
Manganese: more than a stain problem
Many well owners know manganese as the cause of black or brown stains on sinks and laundry and a bitter, metallic taste. The EPA's secondary standard for manganese is 0.05 milligrams per liter. That standard is about appearance and taste, not health, and it is not enforced.
Manganese is also an essential nutrient, and food is the main way most people take it in. At higher levels in water, health is the concern. The EPA's lifetime health advisory for manganese in drinking water is 0.3 milligrams per liter, and the agency advises using that same level even for short exposures in infants younger than 6 months.4
The research behind the infant and child caution is still developing. In one Quebec study of 362 children in communities served by groundwater, higher manganese in home tap water was associated with lower IQ scores.5 It was a cross-sectional study, so it shows a link, not proof of cause. Still, if you mix infant formula with well water, a manganese test is worth doing.
How to test your well
- Use a certified lab. Penn State Extension and DEP both point to accredited drinking water labs.
- Ask for arsenic and manganese by name. Add lead if you have older plumbing.
- Follow the lab's sampling instructions about which tap to use and whether to let the water run first.
- Compare results to the benchmarks: 10 micrograms per liter for arsenic, 0.3 milligrams per liter for manganese.
- If a result is high, get advice from more than one water treatment professional before choosing a system, and retest after treatment is installed.
When body testing makes sense
For arsenic, the urine test is the most reliable way to measure arsenic exposure over the last few days. If your well is high, the most useful result is often a water test after treatment, not a urine test. A urine test can make sense if you have been drinking from a high-arsenic well and want a baseline, or if you have symptoms and a clinician wants to check.
One catch: seafood contains a form of arsenic called arsenobetaine, which is much less harmful but can raise a total urine arsenic result. A lab that separates the forms, or skipping seafood before the test, avoids a false alarm.
For manganese, body tests are much less helpful. The body normally contains manganese and clears extra within days, so blood and urine tests do a poor job of showing past exposure.6 The well test is the real answer.
Your next step
If a well test comes back high and you want to understand body testing, read arsenic urine tests and seafood and blood vs urine vs hair metal testing. The heavy metals testing hub brings the whole series together.
Frequently asked questions
Does boiling well water remove arsenic or manganese?
No. Boiling does not remove metals and can concentrate them as water evaporates. Treatment that is matched to your test results is the fix.
How often should I test my well for arsenic?
A first, baseline test is the key step, since many wells have never been checked. Retest after any treatment is installed, and ask a certified lab or Penn State Extension how often to recheck your well.
Is it safe to shower in water with arsenic?
The main risk from arsenic is swallowing it, not skin contact. Treating or replacing drinking and cooking water addresses most of the exposure.
Can I use well water with high manganese for baby formula?
If your well is above the advisory level, use a different water source for formula and talk with your child's pediatrician.
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.
