Manganese and arsenic are widespread in Lake County wells.

2 widespread, 1 worth checking, 3 rare out of 6 health checks.

From 47 wells tested in Lake County since 2000; your own well needs its own test. How to read this

Tested wells over the limit LakeIndiana

Manganese57%21 of 37 Arsenic42%13 of 31 Nitrate5%2 of 37 Uranium0%0 of 31 Lead0%0 of 31 Fluoride0%0 of 34

GermsTest every year, whatever the chart says

E. coli0%0 of 10

StainsNot a health risk

Iron stains89%33 of 37

Not charted, because fewer than 10 wells were tested: radon (3).

Rare: under 5%Worth checking: 5 to 15%Widespread: 15%+

Lab results: Water Quality Portal (USGS and EPA)

Show bacteria and iron

Who drinks from a well here

About 1 in 17 people 29,518 people

Nobody else tests these wells. Only you do.

People on wells: EPA researchers' 2020 estimate

How deep wells go here

Middle depth: some shelter from the surface, not complete.

Well depths: US Groundwater Well Database

Radon risk (a gas from rock)

LowMiddleHigh

Possible here. A home air test is inexpensive.

Radon zones: EPA map

Here's how Lake County compares with Indiana and the counties around it.

Each result puts Lake County next to the 6 counties that border it, on the chart's 0 to 50% scale.

These 2 are widespread in Lake County wells.

Manganese21 of 37 wells over

About 6 in 10 wells tested here from 2000 to 2023 were over the EPA health advisory of 0.3 mg/L, against about 1 in 4 across Indiana. Half the results were under 0.33 mg/L, and the top 1 in 10 were 1.1 mg/L or more. That's the highest share among the 6 Indiana counties with 10 or more tested wells.

Lake and its neighbors

Lake57%

Cook, IL27%

Jasper16%

Newton6%

Too few tested to show: Kankakee, IL, Porter, Will, IL.

Manganese guide

Arsenic13 of 31 wells over

About 4 in 10 wells tested here from 2000 to 2023 were over the EPA limit of 10 µg/L, against about 2 in 10 across Indiana. Half the results were under 4.0 µg/L, and the top 1 in 10 were 24 µg/L or more. That's the highest share among the 5 Indiana counties with 10 or more tested wells.

Lake and its neighbors

Lake42%

Newton6%

Jasper5%

Too few tested to show: Cook, IL, Kankakee, IL, Porter, Will, IL.

Arsenic guide

This one is worth checking in Lake County.

Nitrate2 of 37 wells over

2 of 37 wells tested here from 2000 to 2023 were over the EPA limit of 10 mg/L, against about 1 in 13 across Indiana. At least half the results were too low for the lab to measure, and the top 1 in 10 were 6.7 mg/L or more. That's a bigger share than in 3 of the 6 other Indiana counties with 10 or more tested wells.

Lake and its neighbors

Kankakee, IL29%

Newton12%

Lake5%

Jasper5%

Porter4%

Too few tested to show: Cook, IL, Will, IL.

Nitrate guide

These 3 are rare in Lake County.

Uranium0 of 31 wells over

None of the 31 wells tested here from 2000 to 2023 were over the EPA limit of 30 µg/L, against none across Indiana. At least half the results were too low for the lab to measure, and the top 1 in 10 were 3.9 µg/L or more. Lake County had none, and neither did any of the 4 other Indiana counties with 10 or more tested wells.

Lake and its neighbors

Jasper0%

Lake0%

Newton0%

Too few tested to show: Cook, IL, Kankakee, IL, Porter, Will, IL.

Uranium guide

Lead0 of 31 wells over

None of the 31 wells tested here from 2000 to 2023 were over the EPA action level of 15 µg/L, against none across Indiana. Lake County had none, and neither did any of the 4 other Indiana counties with 10 or more tested wells.

Lake and its neighbors

Jasper0%

Lake0%

Newton0%

Too few tested to show: Cook, IL, Kankakee, IL, Porter, Will, IL.

Lead guide

Fluoride0 of 34 wells over

None of the 34 wells tested here from 2000 to 2021 were over the EPA limit of 4 mg/L, against none across Indiana. Half the results were under 0.51 mg/L, and the top 1 in 10 were 1.0 mg/L or more. Lake County had none, and neither did any of the 4 other Indiana counties with 10 or more tested wells.

Lake and its neighbors

Cook, IL0%

Jasper0%

Lake0%

Newton0%

Too few tested to show: Kankakee, IL, Porter, Will, IL.

Too few Lake County wells were tested for this one.

Radon in water3 wells tested

Only 3 wells here were tested in 2000, too few to say how common it is. Across Indiana it's none.

Radon guide

Every well needs a bacteria test every year.

E. coli0 of 10 wells had it

None of the 10 wells tested here from 2017 to 2018 had E. coli, against about 1 in 33 across Indiana.

E. coli means human or animal waste is getting in, so if a test of your Lake County well finds it, boil drinking water until the well is fixed.

Bacteria guide

Iron reached staining levels in 33 of 37 tested wells, and it isn't a health risk.

Iron stains33 of 37 wells had it

About 9 in 10 wells tested here from 2000 to 2023 had enough iron to stain (0.3 mg/L), against about 5 in 10 across Indiana.

Lake and its neighbors

Lake89%

Newton59%

Cook, IL55%

Jasper47%

Too few tested to show: Kankakee, IL, Porter, Will, IL.

Iron guide

About 4 in 10 of the 47 wells tested in Lake County have a test from 2020 or later.

11 wells had a test in the 2000s, 18 in the 2010s and 21 since 2020.

With 21 wells tested since 2020, age matters less here than who did the testing and why.

Most Lake County wells in these records were tested for research or because someone suspected a problem, which can push the shares above what a typical home well would show (how we read the numbers).

One mail-in lab test covers the 4 things to check in Lake County.

Bacteria
Nitrate
Manganese
Arsenic

What Indiana offers well owners

Free testingIDEM's Groundwater Monitoring Network offers free well water testing to eligible private residential wells (2026 announcement at events.in.gov/event/gwmn-welltesting-2026). See the program
Certified labsIndiana's list of certified labs
Well recordsIndiana's well record search

Half the household wells here are shallower than 60 feet.

That comes from 34 household wells in Indiana's drilling records. Most wells of every kind here are 59 to 102 feet deep. Wells as deep as Lake County's are usually better protected from fertilizer and bacteria at the surface, but they can pick up more of what's in the rock, like arsenic and uranium. That's the shallowest typical depth for household wells among the 4 Indiana counties with enough drilling records.

Look up your own well's depth in Indiana's well record search, or see how to find it.

Well depths: US Groundwater Well Database

Here's what we know about radon and PFAS in Lake County.

Lake County is in the EPA's middle radon zone. An indoor air test is cheap and tells you whether to look at your water. Radon guide

Between 2023 and 2025 the EPA had 17 town water systems in Lake County test for PFAS. None found any. No well in Lake County has public PFAS results, so the town systems are the best clue to what's in the groundwater nearby. PFAS guide

Radon zones: EPA Map of Radon Zones. PFAS: EPA tests of town water systems, 2023 to 2025

Next door to Lake County

Cook, IL Jasper

Elsewhere in Indiana

Hancock Wayne Montgomery

All of Indiana

Questions people ask about well water in Lake County

Is well water in Lake County safe to drink?

21 of 37 wells tested in Lake County had manganese over the limit, about 6 in 10. Across Indiana it's about 1 in 4. That's the highest share among the 6 Indiana counties with 10 or more tested wells. So test your own well for manganese before you count on it.

Can I get my well tested for free in Lake County?

IDEM's Groundwater Monitoring Network offers free well water testing to eligible private residential wells (2026 announcement at events.in.gov/event/gwmn-welltesting-2026). If not, use a lab Indiana has certified for drinking water. Ask for bacteria, nitrate, manganese and arsenic, the tests that matter most in Lake County.

How deep are wells in Lake County?

Half the household wells here are shallower than 60 feet. That's the shallowest typical depth for household wells among the 4 Indiana counties with enough drilling records.

How does Lake County compare with the counties around it?

For manganese, the share of tested wells over the limit: Lake County, at 57%, had a higher share than all 3 neighboring counties with data. Groundwater doesn't stop at county lines, so Cook, IL's 27% is worth knowing about if you live near it.

How often should I test my well in Lake County?

Lake County has no public bacteria results for wells, so follow the CDC's advice: test for bacteria and nitrate every year, and right away after a flood, a repair, or any change in taste or smell.

By the Tested Water teamData from the USGS, EPA and Indiana Department of HealthUpdated November 8, 2026

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Where the Lake County numbers come from

People on wells: 29,518 in Lake County, from EPA estimates built on the 2020 Census (Murray et al.).
Lab tests: 456 well water samples from 47 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2023.
Well depths: 34 Indiana drilling records for Lake County, gathered in the US Groundwater Well Database (Lin and others, 2024).
Neighboring counties: the 6 counties that share a border with Lake County, from the Census Bureau's county adjacency file.
PFAS: EPA tests of 17 town water systems in Lake County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
Radon: Lake County is zone 2 on the EPA Map of Radon Zones.
State programs and links: Indiana Department of Health, checked November 1, 2026.

Download this county's data (CSV)How we read these numbers Report an error