Well water in Franklin County, Pennsylvania

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Testing recommended

tested well samples in Franklin County exceeded the EPA limit for nitrate (10 mg/L), based on public data from USGS Water Quality Portal.

The strongest signal is total coliform: 40% of 242 local wells tested were above the EPA limit, too few samples to carry the headline but first on the test list below.

242 private wells tested 2007 to 2025 in state summaries; 2,024 test results across 15 contaminants from at least 72 wells, 1925 to 2026; nitrate has the most at 373. 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 52,824 people in Franklin County get their drinking water from a private well, per USGS 2015 county water use. That is about 34% of residents.

Separately, the USGS national arsenic model estimates that <1% of the 52,824 people on private wells in Franklin 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	Highest	State level
Total coliform	40%	242		201	0 MPN/100mL
Manganese	27%	81	10	3,640	50 ug/L
Iron	22%	74	100	14,800	300 ug/L
Nitrate + nitrite as N	17%	119	2.3	15.4	10 mg/L
E. coli	12%	242		201	0 MPN/100mL
Lead (first draw)	12%	43		66	15 ug/L
Copper	0%	80	0.01	0.47	1.3 mg/L
Arsenic	0%	46		5	10 ug/L
Chloride	0%	8	45.9	220	250 mg/L
Sodium		6	157	199

What individual samples found

Each row summarizes every public sample for that contaminant inside Franklin 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
Nitrate 1925 to 2026	10%	373	55%	0.075	179	10 mg/L EPA limit
Fluoride 1957 to 2026	0%	214	97%	0.21	1.6	4 mg/L EPA limit
Copper 1957 to 2026	0%	214	45%	0	0.11	1.3 mg/L EPA limit
Arsenic 1978 to 2026	0%	202	50%	0	6.5	10 ug/L EPA limit
Lead 1978 to 2026	0%	189	19%	0	5.6	15 ug/L EPA limit
Uranium 1993 to 2024	0%	22	68%	0.332	0.8	30 ug/L EPA limit
Manganese 1957 to 2026	no limit	233	86%	150	3,600	300 ug/L health guideline
Iron 1925 to 2026	no limit	224	71%	110	45,000	300 ug/L nuisance level
Chloride 1925 to 2026	no limit	222	95%	3.4	178	250 mg/L nuisance level
Sodium 1925 to 2026	no limit	89	99%	9.48	187	20 mg/L health guideline
Radon 1993 to 2019	no limit	15	93%	420	1,000	2,000 pCi/L health guideline

Sampled fewer than 10 times, too few to summarize: PFOS (9), PFOA (9), E. coli (7), Radium (226 + 228) (2).

Over time

Share of samples above the limit by period. A cell needs ten samples to show; a comparison needs twenty in each period. Later periods sample fewer wells, and often the ones already known to have a problem.

Contaminant	before 2000	2000s	2010s	2020s
Nitrate	33%76 samples	17%24 samples	3%124 samples	3%149 samples
Copper	0%14 samples	n/a	0%88 samples	0%107 samples
Fluoride	0%40 samples	n/a	0%80 samples	0%87 samples
Arsenic	0%19 samples	0%11 samples	0%85 samples	0%87 samples
Lead	0%17 samples	n/a	0%80 samples	0%87 samples

Nitrate, copper, fluoride, arsenic, lead have held within a few points between the two most recent periods with enough samples.

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 address

What this means

Among homeowners in Franklin County who sent a sample to the state lab, the health-based limits most often exceeded were total coliform (40% of 242 wells), nitrate (17% of 119 wells), and E. coli (12% of 242 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 Franklin County

1
Total coliform
40% of 242 local wells tested were above the EPA limit.
2
Nitrate
17% of 119 local wells tested were above the EPA limit.
3
E. coli
12% of 242 local wells tested were above the EPA limit.
4
Lead
12% of 43 local wells tested were above the EPA limit.
5
Radon
Median local reading is 420 pCi/L.
6
Manganese
27% of 81 local wells tested were above the EPA secondary standard.
7
Iron
22% of 74 local wells tested were above the EPA secondary standard.
8
PFOS
Above the limit in 2 of 9 local samples; too few to quote a rate.

Test your Franklin County well for total coliform, nitrate 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 $209 Already 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 Franklin County numbers, $29. Every line explained, ranked by what matters, with the fix for each.

Wells in Franklin County

7,225 domestic wells in Franklin County are on record with the state. 100% are drilled into bedrock, and the typical well is 195 feet deep (one in ten goes past 430 feet).

In a typical Franklin County well, bedrock starts about 30 feet down, the median yield is 15 gallons per minute, 9% 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 Franklin County

Valley and Ridge aquifers

Sandstone and carbonate-rock. Layered sandstone and limestone means a well may draw from either. Hardness and iron are routine, and the limestone layers can carry bacteria and nitrate from the surface quickly, so test for both yearly.

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

Nitrate

Point-of-use reverse osmosis; Anion exchange; Distillation

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

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 nitrate

Under-sink reverse osmosis system

under-sink or countertop, about $300

Look for NSF/ANSI 58 certification listing the contaminant you need removed.

For nitrate

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 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

Aquasana Claryum 3-Stage under-sink filter

under-sink or countertop, about $175

Certified to NSF/ANSI 53 to reduce 99% of lead and 99.7% of PFOA and PFOS at the tap. Not a fix for arsenic, nitrate or bacteria.

For lead

Acid neutralizing filter

whole-house, at the point of entry, about $1,200

Raises pH so plumbing stops leaching lead and copper.

Free, no obligation

Get on the list for a free in-home water test in Franklin County

No water treatment company serves Franklin 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 Franklin County, and you get an email naming it first.

Common questions

How deep are wells in Franklin County?

The typical domestic well in Franklin County is 195 feet deep, based on 7,225 wells reported to the state. One in ten is deeper than 430 feet. 100% are drilled into bedrock.

Is there arsenic in well water in Franklin County?

Arsenic was detected in 50% of 202 public well samples in Franklin County, and 0% 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 high is radon in well water in Franklin County?

The median radon level across 15 public samples in Franklin County was 420 pCi/L, with a high of 1,000 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.

How often should I test a private well in Franklin 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 Franklin County

20 towns have fewer than 30 public samples and are included in the Franklin County totals above rather than shown separately: Antrim township, Chambersburg borough, Fannett township, Greencastle borough, Guilford township, Hamilton township, Lurgan township, Mercersburg borough, Metal township, Mont Alto borough, Montgomery township, Orrstown borough, Peters township, Quincy township, Shippensburg borough, Southampton township, St. Thomas township, Warren township, Washington township, Waynesboro borough.

Counties near Franklin 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: 2,024 samples in Franklin 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 Franklin County, up to 242 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 52,824 people on private wells in Franklin 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: 9,515 well records in Franklin County, 7,225 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.