A buyer moving to Tewksbury Township from a town with municipal water and sewer usually hits the same wall about three weeks into contract: someone mentions the well test. New Jersey's Private Well Testing Act requires it, the seller's attorney has a checklist for it, and the closing timeline has a line item for it. The instinct, understandably, is to treat that mandated test as the full picture of what's in the water and move on to the next inspection.
That instinct is where the trouble starts. The state's required panel is real and it does catch a lot. But it was written to cover New Jersey as a whole, and Tewksbury sits on bedrock that behaves differently than most of the state. Knowing exactly where the required test stops, and what Hunterdon County's own geology adds to the list, is the difference between a clean closing and a renegotiation two weeks before you're supposed to have keys.
Why Nearly Every Tewksbury Address Comes With Two Systems You Own
Tewksbury's zoning was built around keeping lots large and development light, with village districts reserved for hamlet centers and larger farmland-preservation districts covering most of the township. That pattern is also why public water and sewer lines never got extended across most of the town the way they did in denser Hunterdon and Somerset communities. If you're buying a home on several acres here, you are very likely buying a private well and a private septic system along with it, and both of those systems become entirely your responsibility the day you close.
There's one meaningful exception worth knowing if you're looking at property in the historic village center. Oldwick has its own small sewer system, separate from the septic reality that covers most of the rest of the township. The township's own code spells out what happens when a property connects to it: any existing septic tank, cesspool, or seepage pit has to be pumped and properly filled within 45 days of the sewer hookup. If you're comparing a home just inside the village against one a half mile out on farmland-preserved acreage, you're not just comparing architecture. You're comparing two entirely different utility situations with two different due-diligence paths.
What the State Actually Requires You to Test
New Jersey's Private Well Testing Act became law in 2002 and applies to almost every residential sale where the home draws drinking water from a private well. The seller is responsible for having the water tested at a certified lab and sharing results with the buyer, generally within 30 days of closing. Here's what that mandatory panel actually covers:
| Category | What gets tested |
|---|---|
| Bacteria | Total coliform, and E. coli if coliform is detected |
| Core chemistry | Nitrate, lead, arsenic |
| Radioactivity | Gross alpha particle activity |
| Organic compounds | 26 volatile organic compounds, plus select synthetic organics |
| PFAS (added December 2021) | PFOA, PFOS, PFNA |
| Not required anywhere in the state | Radon in water |
That last row is the one worth sitting with, because it's not a minor gap in Tewksbury's case. It's a gap sitting directly on top of the geology that makes it matter most.
The Gap That Matters More Here Than Almost Anywhere in New Jersey
Hunterdon County falls within the Reading Prong, a uranium-bearing rock formation running through northwestern New Jersey, and within the broader Highlands region where wells draw from fractured Precambrian bedrock rather than the sand and soil aquifers found elsewhere in the state. Water moving through fractured rock doesn't get the natural filtering that a soil aquifer provides, and radon dissolves readily into that groundwater as it moves.
The EPA's suggested cap for radon in water is 4,000 picocuries per liter, and New Jersey has discussed a stricter limit closer to 800. In the Reading Prong region, water tests exceeding 10,000 pCi/L aren't unusual, and some wells have measured above 50,000. None of that shows up on the mandatory PWTA report, because radon in water isn't part of the required panel anywhere in the state. A buyer who assumes the state-mandated test is comprehensive will never see this number unless they specifically request it as an add-on test, at their own cost, before closing.
What Local Wells Actually Turn Up
Radon isn't the only regional pattern worth knowing about. Raritan Headwaters Association, the nonprofit watershed group covering Hunterdon, Somerset, and Morris counties, has tested private wells across its service area and found more than half showed detectable arsenic, with roughly 12 percent above New Jersey's Maximum Contaminant Level. Arsenic occurs naturally in the Piedmont-region bedrock underneath much of the county, and it's colorless and tasteless, so there's no way to notice it without testing. Boron often turns up alongside it in Hunterdon wells specifically, another naturally occurring element tied to the same rock formations.
Arsenic is part of the required PWTA panel, so a well that's failing on that front will show up in the mandatory results. Boron and radon won't, because neither is part of the required list. If you're under contract on a Tewksbury property, asking your lab to add both to the standard panel is a small cost against a large blind spot.
Disclosure Is Not the Same as a Fix
Here's the part that catches even careful buyers off guard. The Private Well Testing Act is a disclosure law, not an enforcement mechanism. If a test comes back with arsenic above the state limit or a PFAS compound over the threshold, the seller has to hand you the results. Nothing in the law requires anyone to treat the water or reduce the price. Local health departments get notified automatically when a primary standard is exceeded, but they aren't required to intervene.
That means the negotiation over a bad water test happens entirely at the contract level. If you want treatment installed, a price credit, or an escrow holdback for remediation, that has to be something you or your attorney raises as a condition of the deal. A test result alone doesn't obligate anyone to act on it.
The Septic Side: No Statewide Mandate, but the County Still Checks
Septic works differently than well testing in one important way: there's no single New Jersey law requiring an inspection before every home sale. It's decided municipality by municipality, and lenders and buyers typically require one anyway to avoid inheriting a failing system. When an inspection does happen, it follows a specific state protocol.
For Tewksbury specifically, Hunterdon County's Office of Environmental Health handles site inspections, design review, and final certification for septic systems in the township, and the county keeps a browsable record of septic design approvals by municipality. That's a useful, verifiable resource if you want to see what's on file for a specific parcel before you're deep into attorney review.
Age matters more than most buyers expect here too. New Jersey's own technical guidance for septic inspections is direct about this: systems older than 20 years generally don't meet current standards and are likely to need repair or replacement even if they're functioning normally at the moment of inspection. A system can pass its inspection and still be a five-figure liability within a few years of your purchase.
A Due-Diligence Timeline Built for Tewksbury, Not for a Municipal-Served Town
If you're used to buying in a town with public water and sewer, the timeline here needs more runway than you'd expect:
- Roughly 8 weeks before your target closing: order the PWTA-required well test through a certified lab, and ask for radon and boron to be added to the standard panel given the county's bedrock.
- 2 to 3 weeks later: expect lab results. If something needs treatment, this is your window to negotiate before the closing date gets tight.
- For sellers, 30 to 45 days before listing: schedule the septic inspection so a failed result doesn't collide with a buyer's own clock later.
- Anytime during attorney review: check whether the property's septic design approval is on file with Hunterdon County, and note that a standard septic inspection is generally considered valid for about two years, so a recent report on an older home may already be aging out.
None of this is complicated once you know it's coming. It's only a problem when a buyer discovers the radon add-on exists after the inspection contingency has already expired.
A Few Questions Worth Asking Directly
Does every Tewksbury home need both a well test and a septic inspection? If the property uses a private well, the PWTA test is required by state law regardless of the township. Septic inspection requirements are set locally, but lenders and most purchase contracts require one in practice, and Hunterdon County reviews and certifies septic designs directly.
What if the well test finds something the seller didn't know about? The result still has to be disclosed to you. What happens next, whether that's a price adjustment, an escrow credit, or a request for treatment before closing, is negotiated through the contract, not required by the testing law itself.
Is a home in Oldwick different from one on the surrounding farmland? Yes. Oldwick's village center has its own small sewer system, separate from the septic systems that serve most of the rest of the township, which changes the due-diligence questions you'd ask about that specific property.
Tewksbury's rural character and its farmland preservation are exactly what draws people here, and they're also the reason the utility questions look different than they would in a town ten minutes away with a sewer main under the street. Working through a well and septic transaction correctly the first time protects both the timeline and the number on the closing statement.
If you're weighing a purchase or preparing to list a property in Tewksbury and want a clear read on what a specific parcel's well and septic history actually looks like, Berly Young has spent two decades guiding buyers and sellers through exactly this kind of due diligence across Hunterdon County. Let's Connect.
