Somers Homes on Well Water Can't Skip This Test. They Can't Do It Early, Either.

Most advice about selling a house on a private well says the same thing: test the water before you list, so you know what you're dealing with before a buyer's inspector finds it first. In Somers, that advice doesn't hold. Westchester County has its own law governing well water testing in a real estate sale, and it doesn't care what your water tested like six months ago. It only cares what happens after a contract is signed.

That single fact catches out-of-area buyers and even some local sellers off guard, because it runs against what every national buying guide tells you to expect.

The test is mandatory, not optional

Under Westchester County's Private Well-Water Testing Law, Local Law 7 of 2007, any home in the county served by a private well triggers a water test the moment both parties sign a contract of sale. The seller arranges it. The seller pays for it. Neither the buyer nor the seller can write it out of the contract, because the testing laboratory is required to send results directly to the Westchester County Department of Health regardless of what the two parties agree to privately.

The mechanics run on a strict clock:

• Within 10 days of contract execution, the seller must give the buyer written confirmation that the test has been ordered.
• Within 5 days of getting results back from the lab, the seller must hand them to the buyer.
• Both parties then have to certify in writing that they received and reviewed the results.

None of this is negotiable. A purchase agreement that tries to waive the testing requirement doesn't hold up against the county code.

Why your pre-listing test doesn't count

Sellers who had their well tested before putting the house on the market, following the standard advice to get ahead of surprises, often assume that test satisfies the county requirement. It doesn't. Westfair Water says homeowners have to be in contract before the test can be submitted for county compliance, and that a result is only good for one year from the date it's drawn under the law. A test run during listing prep, before any contract exists, doesn't start that clock in a way the county recognizes for the sale.

That means the sequence a national guide recommends, test early, list with confidence, gets replaced in Somers by a sequence where the real test can't even be scheduled until you're already under contract with a buyer.

Who's allowed to collect the sample

The law also specifies who can and can't take the water sample. Sterling Home Inspections says it has to be an employee or authorized representative of a laboratory certified by the New York State Department of Health. A homeowner can't collect it. Neither can a real estate agent, even one holding the listing. This isn't a matter of preference. The county's own guidance on the law states plainly that a real estate agent may not collect samples unless that agent also happens to be an employee of a certified lab, which in practice means never.

That detail matters for timeline planning, because it means the sample collection has to be scheduled as its own appointment with a lab, not folded into a general home inspection visit the way a buyer might expect.

What actually gets tested, and what a failure means

The panel covers primary contaminants: total coliform bacteria, nitrate, arsenic, lead, a set of primary organic compounds under Part 5 of the New York State Sanitary Code, vinyl chloride, and methyl-tertiary-butyl-ether. Alongside those, the test also covers secondary parameters that affect taste and appearance rather than health: pH, iron, manganese, sodium, and chloride.

The distinction between primary and secondary matters. For arsenic specifically, the current maximum contaminant level is 0.010 milligrams per liter, and Westchester County Department of Health says a result above that threshold obligates the property owner to install treatment after other remedial steps have been tried.

Until a primary contaminant issue is resolved, the property owner has to keep providing potable water to anyone occupying the home. The county backs this up with real penalties: Dolgetta Law says violations can draw a fine, and a property that isn't providing potable water after a failed test can be fined an additional amount for every day the condition goes uncorrected.

The timeline math nobody budgets for

Here's where the friction actually lands on a closing date. Stack the required steps end to end:

A well that's been sitting unused for three weeks or more, common with an estate sale or a long-vacant property, needs chlorination before the sample can even be drawn, and the test can't happen until a week after that treatment. Add that to the standard turnaround and a buyer expecting a 30-day close can watch the well-water piece alone eat two to three weeks of it, independent of anything else moving on the file.

Why this isn't abstract in Somers

Somers isn't a town where private wells are a rare exception. Town water service runs through the Somers Consolidated Water District No. 1, which the town board reorganized in 2021 after folding in the former Amawalk Heights Water District. The Heritage Hills community runs on a separate system entirely, the Heritage Hills Water Works Corporation, maintained not by the town but by Veolia Water. Outside those service areas, a meaningful share of Somers households draw drinking water from private wells.

The Somers Land Trust's work protecting the aquifer beneath Rhinoceros Creek Reservation makes the stakes concrete rather than theoretical. The trust's own mapping shows homes and small businesses pressing against the edges of that aquifer, many served by private septic systems sitting close to the same groundwater that feeds nearby wells, with portions of the New York City watershed layered on top of the same water table. Failing septic systems, along with lawn fertilizer and pesticide runoff, can work their way into that aquifer over time. That's the backdrop the county law is actually responding to. It's why the testing requirement isn't paperwork for its own sake in a town like Somers.

What this means if you're on either side of a Somers contract

If you're selling a well-served home, the practical move is to line up a certified lab before you're deep into contract negotiations rather than after, so the 10-day clock doesn't catch you flat-footed. If the house has been vacant, plan for the chlorination step from the start rather than discovering it mid-contract. And treat any pre-listing water test as informational for your own peace of mind, not as something that satisfies the county requirement once you have a signed contract in hand.

If you're buying, build the lab lead time and possible remediation cycle into your expectations for the closing date before you sign, rather than assuming the well test is a quick formality that clears in a few days. A 30-day contingency period that looks generous on paper can get consumed almost entirely by lab scheduling and chlorination waiting periods if the timing runs against you.

A few questions that come up often

Can a buyer and seller just agree to skip the test? No. The law requires the laboratory to report results directly to the Westchester County Department of Health, which is precisely what makes the requirement unwaivable between private parties.

If the seller already installed a whole-house filtration system, does the well still need testing? Yes. The county's guidance is direct on this point: a well with treatment installed still has to be tested under the law.

What if the well has been sitting unused because the house is vacant? It still has to be tested, and in most cases it will need chlorination first, followed by a mandatory waiting period before the sample can be drawn. Vacant properties are exactly where this timeline tends to run long.

A well water test sounds like a small line item next to inspections, appraisals, and mortgage underwriting. In Somers, it's one of the few pieces of a transaction with its own legal clock, its own required vendor, and its own paper trail to the county health department. Getting the sequence right from the day a contract is signed is the difference between a closing date that holds and one that slides by weeks.

If you're weighing a purchase or a sale on a well-served property in Somers and want to map out what this timeline actually looks like for your situation, Marcie Nolletti can walk through it with you before you're under contract, not after.

This article is general information, not legal, tax or financial advice. Consult a qualified professional about your situation.