Well water in Clarion County, Pennsylvania
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Testing strongly recommended
tested well samples in Clarion County exceeded the EPA limit for arsenic (10 ug/L), based on public data from USGS Water Quality Portal.
The strongest signal is total coliform: 53% of 120 local wells tested were above the EPA limit, too few samples to carry the headline but first on the test list below.
120 private wells tested 2007 to 2025 in state summaries; 7,376 test results across 13 contaminants from at least 158 wells, 1969 to 2025; manganese has the most at 1,261. Data refreshed September 16, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
These are samples homeowners paid to send to the Penn State lab, often because of a suspected problem, so shares above the limit run higher than a random survey would find.
An estimated 22,073 people in Clarion County get their drinking water from a private well, per USGS 2015 county water use. That is about 56% of residents.
Separately, the USGS national arsenic model estimates that 1% of the 22,073 people on private wells in Clarion County draw water above 10 ug/L (the model's range is <1% to 1%), from geology and well depth rather than local tests.
What homeowner tests found
Penn State Agricultural Analytical Services Lab drinking water summaries: private wells tested and reported to the state, 2007 to 2025. Shares are against the level the state applies to each contaminant, named in the last column; several are stricter than EPA.
| Contaminant | Above state level | Wells tested | Median | 95th pct | Highest | State level |
|---|---|---|---|---|---|---|
| Manganese | 22 | 260 | 4,700 | 50 ug/L | ||
| Total coliform | 120 | 1 | 201 | 0 MPN/100mL | ||
| Iron | 17 | 100 | 52,300 | 300 ug/L | ||
| E. coli | 120 | 201 | 0 MPN/100mL | |||
| Lead (first draw) | 95 | 238 | 15 ug/L | |||
| Copper | 63 | 0.02 | 1.42 | 1.3 mg/L | ||
| Nitrate + nitrite as N | 91 | 0.4 | 9.6 | 10 mg/L | ||
| Arsenic | 80 | 5 | 10 ug/L | |||
| Chloride | 10 | 4.5 | 116 | 250 mg/L | ||
| Sodium | 23 | 36.2 | 154 |
What individual samples found
Each row summarizes every public sample for that contaminant inside Clarion County. Above limit means above the EPA maximum contaminant level; where EPA has no enforceable limit, the row shows a health guideline or nuisance level instead.
| Contaminant | Above limit | Samples | Detected | Median | Highest | Limit |
|---|---|---|---|---|---|---|
| Arsenic 1986 to 2025 | 758 | 44% | 0 | 1,000 | 10 ug/L EPA limit | |
| Lead 1973 to 2025 | 782 | 26% | 0 | 1,800 | 15 ug/L EPA limit | |
| Copper 1971 to 2025 | 793 | 71% | 0.03 | 5 | 1.3 mg/L EPA limit | |
| Fluoride 1971 to 2025 | 59 | 73% | 0.2 | 7.4 | 4 mg/L EPA limit | |
| Nitrate 1971 to 2025 | 795 | 30% | 0 | 40 | 10 mg/L EPA limit | |
| Manganese 1969 to 2025 | no limit | 1,261 | 98% | 42,000 | 800,000 | 300 ug/L health guideline |
| Iron 1969 to 2025 | no limit | 1,250 | 100% | 140,000 | 3,200,000 | 300 ug/L nuisance level |
| Chloride 1969 to 2025 | no limit | 851 | 96% | 3 | 857 | 250 mg/L nuisance level |
| Sodium 1969 to 2025 | no limit | 807 | 99% | 5.6 | 340 | 20 mg/L health guideline |
Sampled fewer than 10 times, too few to summarize: Uranium (8), Radium (226 + 228) (2), E. coli (2), Radon (8).
Closer than the county
See the sampled wells near your address
The same records, drawn around one point: which wells within a few miles were sampled and what they found, how deep the wells next to you were drilled, and any leaking tank or cleanup site within a mile.
Check my addressWhat this means
Among homeowners in Clarion County who sent a sample to the state lab, the health-based limits most often exceeded were total coliform (53% of 120 wells), E. coli (26% of 120 wells), and lead (16% of 95 wells). These are ordinary wells tested by their owners, so the shares are the best available picture of a typical well here, with one caveat: people test more often when they suspect a problem.
Manganese and iron exceed the state's advisory level in a sizable share of wells; these are mostly a taste, staining or diet issue rather than a toxicity one.
What to test for in Clarion County
- 1Total coliform53% of 120 local wells tested were above the EPA limit.
- 2Arsenic36% of 758 local samples were above the limit.
- 3E. coli26% of 120 local wells tested were above the EPA limit.
- 4Lead16% of 95 local wells tested were above the EPA limit.
- 5Copper2% of 793 local samples were above the limit.
- 6Fluoride2% of 59 local samples were above the limit.
- 7Nitrate<1% of 795 local samples were above the limit.
- 8Manganese59% of 22 local wells tested were above the EPA secondary standard.
Test your Clarion County well for total coliform, arsenic and E. coli
Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.
Order the Tap Score well water test kit, from $209Already tested? Upload the report
Just want bacteria checked first? Tap Score coliform and E. coli test, $99. Coliform and E. coli are the tests every well needs every year.
Want a quick look before paying for a lab? Home well water test strips on Amazon check hardness, iron, pH and nitrate in minutes. They are a screen, not a result: arsenic, bacteria, uranium and PFAS need a certified lab.
Affiliate links: the merchant pays us a commission and the price is the same for you. It does not change what the data above says. As an Amazon Associate we earn from qualifying purchases.
Where to get a well tested in Pennsylvania: certified labs, state programs and prices.
Already have results back? Get your lab report read against the Clarion County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
Wells in Clarion County
1,388 domestic wells in Clarion County are on record with the state. 100% are drilled into bedrock, and the typical well is 90 feet deep (one in ten goes past 200 feet).
In a typical Clarion County well, bedrock starts about 14 feet down, the median yield is 10 gallons per minute, 6% of wells yield under 3 gallons per minute and usually need a storage tank.
Bedrock wells are where arsenic, uranium and radon come from: the water sits in fractures in granite and metamorphic rock and picks up whatever the rock carries. That is why testing for those three matters more here than in a dug or gravel well.
Find your own well's report
The state keeps the driller's report for most wells drilled since 1984. It tells you how deep your well is, where bedrock starts, and how much water it makes, which decides what treatment can work.
- Open PaGWIS (Pennsylvania Geological Survey) and choose Water Well.
- The record lists depth, depth to bedrock, yield and use; drillers have reported new wells to the state since 1966.
Pennsylvania has no private well construction standard and does not require testing, so many older wells have no record at all.
The rock under Clarion County
Pennsylvanian aquifers
Sandstone. Sandstone wells draw from pore space in the rock and tend to be dependable. Iron, manganese and hardness are common, and some sandstones carry arsenic or radium, so a first test should include both.
Classification from the USGS Principal Aquifers of the United States (national map, 2003 edition, GIS release 2015), read at the county centroid. A single well can sit in a different unit, especially near a boundary.
Official help in Pennsylvania
Two places to start that are not selling anything: the state program that answers private well questions, and its list of labs certified to run drinking water tests. A certified lab is the difference between a result you can act on and a number.
- Private Wells, PA DEP
- Laboratory Accreditation Program, PA DEP
Treatment that fits the local profile
Total coliform
Inspect and repair the well cap and casing, then shock chlorinate and retest; UV disinfection whole-house; Chlorination system
E. coli
Shock chlorination and fix the well cap or casing; UV disinfection whole-house; Chlorination system
Lead
Point-of-use reverse osmosis; Certified lead-removal carbon filter; Neutralizing filter to raise pH and stop leaching
Manganese
Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
Iron
Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
Arsenic
Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
Systems we would look at first
Some links below are affiliate links. If you buy through one, the merchant pays us a commission at no extra cost to you. It does not change which products we list or what the data says.
For total coliform
Aquasana Rhino Well Water with UV
whole-house, at the point of entry, about $2,871
Whole-house system built for wells: sediment pre-filter, KDF and carbon, and a UV lamp rated to kill 99.99% of bacteria and viruses. It does not remove arsenic, nitrate, uranium or radon.
For E. coli
UV disinfection system
whole-house, at the point of entry, about $900
Fix the well cap and casing first; UV keeps bacteria from returning.
For lead
Under-sink reverse osmosis system
under-sink or countertop, about $300
Look for NSF/ANSI 58 certification listing the contaminant you need removed.
For lead
Acid neutralizing filter
whole-house, at the point of entry, about $1,200
Raises pH so plumbing stops leaching lead and copper.
For lead
Aquasana SmartFlow reverse osmosis
under-sink or countertop, about $225
Certified to NSF/ANSI 58 and 53 to reduce arsenic (96%, pentavalent), fluoride (90%), lead (99%), nitrate, nitrite and PFOA/PFOS at the kitchen tap, with a remineralizer.
For manganese
Iron and manganese oxidizing filter
whole-house, at the point of entry, about $1,800
Air-injection or greensand media; fixes staining at the source.
Free, no obligation
Get on the list for a free in-home water test in Clarion County
No water treatment company serves Clarion County through Well Water Nerd yet. We are signing licensed companies on county by county: they test at your tap for free, walk you through the numbers, and quote treatment only if something needs fixing. Leave your details and you are first in line. Nothing is shared until a company joins for Clarion County, and you get an email naming it first.
Common questions
How deep are wells in Clarion County?
The typical domestic well in Clarion County is 90 feet deep, based on 1,388 wells reported to the state. One in ten is deeper than 200 feet. 100% are drilled into bedrock.
Is there arsenic in well water in Clarion County?
Arsenic was detected in 44% of 758 public well samples in Clarion County, and 36% were above the EPA limit of 10 ug/L. Arsenic has no taste or smell; a lab test is the only way to know your level.
How often should I test a private well in Clarion County?
Test for bacteria and nitrate every year. Test once for arsenic, uranium, radon, fluoride, manganese and PFAS, then again every three to five years or after any change in taste, color, or plumbing.
Towns in Clarion County
33 towns have fewer than 30 public samples and are included in the Clarion County totals above rather than shown separately: Ashland township, Beaver township, Brady township, Callensburg borough, Clarion borough, Clarion township, East Brady borough, Elk township, Emlenton borough, Farmington township, Foxburg borough, Hawthorn borough, Highland township, Knox borough, Knox township, Licking township, Limestone township, Madison township, Millcreek township, New Bethlehem borough, Paint township, Perry township, Porter township, Redbank township, Richland township, Rimersburg borough, Salem township, Shippenville borough, Sligo borough, St. Petersburg borough, Strattanville borough, Toby township, Washington township.
Counties near Clarion County
Closest first. Groundwater does not stop at a line on a map, so the next county over is a fair second opinion.
Want the numbers themselves? Download the Pennsylvania dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 7,376 samples in Clarion County. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
- Penn State Agricultural Analytical Services Lab drinking water summaries: summaries for 10 contaminants in Clarion County, up to 120 wells each. County summaries of private water samples tested by the Penn State Agricultural Analytical Services Laboratory since 2007, published by the College of Agricultural Sciences. Counts are samples, not distinct wells. Shares are against the standard the lab prints: the EPA maximum contaminant level, or the secondary standard for iron, manganese and chloride. Lead is the first-draw result. Medians printed as 0.00 are stored as null because the lab rounds to two decimals. Retrieved September 16, 2026.
- USGS national arsenic model (Ayotte 2017): estimated share of 22,073 people on private wells in Clarion County above 10 ug/L of arsenic, from geology, well depth and land use. County estimates of domestic well users with arsenic above 10 ug/L from the USGS national logistic regression model (Ayotte, Medalie and Qi, 2017), with private well population from the USGS 2015 county water-use compilation (Dieter and others, 2018). Retrieved September 15, 2026.
- Pennsylvania Groundwater Information System (PaGWIS) wells: 1,991 well records in Clarion County, 1,388 domestic. Water well records from the Pennsylvania Groundwater Information System, Pennsylvania Geological Survey (DCNR). Only aggregates are shown; owner names and addresses are never stored. Retrieved September 16, 2026.
Non-detects count as samples and are treated as zero when computing medians. Exactly at the limit counts as not above it. A sample belongs to the town containing the well's reported coordinates.