Well Water Testing in West Amwell Township, NJ

Rural landscape in the Sourlands region of West Amwell Township, Hunterdon County, NJ.

West Amwell Township was created in 1846 when the original Amwell Township was divided, taking its name from Great and Little Amwell in Hertfordshire, England. The Delaware River forms its western border with Pennsylvania, and the township spans two landscapes, the Amwell Valley to the north and the rockier Sourlands region to the south. About 3,000 people live across nearly 22 square miles, nearly all on private wells. Its test record is smaller than its neighbors', 406 tests since 2002, but it contains the highest gross alpha rate of any Hunterdon township and one of the highest PFAS rates.

What well tests in West Amwell Township have found

NJDEP's Private Well Testing Act summary (September 2002 to December 2024) covers 406 untreated wells.

Gross alpha: 16.6% of 362 wells exceeded the limit, nearly three times the county's 5.8% and the highest of any Hunterdon township with a large sample. None of 69 wells exceeded the uranium limit, though uranium's sample is smaller.
PFAS: 17.3% of 52 wells tested since late 2021, or 9 of 52, exceeded a PFAS limit, against 4.4% countywide.
Iron and manganese: 26.6% and 20.9%, both well above the county's 16% and 10.9%.
Arsenic: 17.2% exceeded the limit (county: 15.7%).
pH: 17.8% outside the optimum range (county: 28.1%).
Bacteria: total coliform in 23.4%; E. coli in 3.7%.
Nitrate and solvents: 1.5% and 0.2%.

The rock beneath West Amwell

The NJ Geological Survey's generalized map puts about 74% of the township on Triassic sedimentary rock of the Newark Basin and 26% on Jurassic diabase, the dark igneous rock associated with the Sourlands. That is more diabase than any other Hunterdon township. Research on the Newark Basin ties elevated arsenic and radioactivity to its red mudstone and siltstone, but the diabase and the sedimentary rock meet in a complicated way. The result is a township where a wide range of results is plausible, and a neighbor's result is only a rough guide.

What the PFAS numbers do and do not say

PFAS joined the required panel in December 2021, so the sample behind West Amwell's figure is small, 52 wells. Nine flagged wells is a real finding, but it is not a rate to forecast a specific property with. What it does justify is not skipping the PFAS line on a West Amwell report and, if a result is flagged, asking the lab about the specific compound and concentration. PFAS chemistry covers thousands of compounds, and the required panel checks three of them. See PFAS testing for wider screens and our PFAS overview.

Public water or a private well?

NJDEP's 2017 purveyor map shows about 1.9% of the township inside a mapped public service area, an edge of the Lambertville water system. Nearly every home is on a private well. Lambertville, the neighboring city, is a different case, with nearly all of it on a public system.

Buying or selling in West Amwell Township

Sellers should not expect a routine report.

Watch gross alpha and PFAS. Both are flagged here more often than the county norm, and both can extend the timeline.
Iron and manganese are common. Ask about softeners and filters.
Ask for treatment quotes early. If more than one line is flagged, the equipment may need to address several issues.

Both parties must receive and review the results before closing, and the contract decides who pays. See the PWTA page and the treatment referral page.

Renting out a property in West Amwell Township

Landlords on private wells retest at least every five years and give each tenant a copy within 30 days of the results. Since PFAS entered the panel in December 2021, any test on file from before then has no PFAS result, and a retest is the first chance to see one. See landlord testing.

How this compares with neighboring towns

Percent of tested wells above the limit for arsenic and gross alpha, or outside the optimum pH range, with the number of wells behind each figure:

Delaware Township: arsenic 21.7%, pH 24%, gross alpha 11.7% (700 wells)
East Amwell Township: arsenic 42.5%, pH 11.2%, gross alpha 6.9% (616 wells)
Lambertville: arsenic 10.7%, pH 23%, gross alpha 1.8% (122 wells)

Questions from West Amwell homeowners

Is a PFAS result a reason not to buy?

Not by itself. It is a reason to understand the compound, the concentration and the treatment options. Treatment for PFAS exists, and the decision depends on the actual numbers.

Why are the Sourlands different?

The Sourlands are underlain by diabase, an igneous rock that behaves differently from the sedimentary rock around it. Diabase covers about 26% of West Amwell, and the mix of the two rocks is why results here can vary widely from one property to the next.

What does a high gross alpha result mean?

It is a broad screen for naturally occurring radioactivity. An elevated result usually leads to more specific analysis to identify the cause. See how to read your test report.

If I am not selling, how often should I test?

The New Jersey Department of Health encourages well owners to test every year for total coliform, nitrate and pH, and at least once for arsenic, mercury, gross alpha and uranium. Given the gross alpha and PFAS results locally, an owner who has never tested for either has particular reason to do so once.

Does the uranium requirement apply?

Yes, for a well. See why Hunterdon requires it.