Southampton, NY Water Quality Testing

Buying a Home on a Private Well: Suffolk County Chapter 840

Suffolk County Code Chapter 840, in effect since 2000, requires a water test before the sale of a home on a private well:

• The buyer must obtain written certification from a New York State-approved laboratory, based on an analysis of the untreated raw water, that the well meets the Suffolk County Department of Health Services water quality requirements for new residential construction.

• The certification is exchanged between buyer and seller at closing.

• If the water does not meet the standard, the buyer notifies the seller within 15 days. The seller can correct the problem or cancel the sale and return the deposit. If the seller will not correct it, the buyer can still agree in writing to close.

• The requirement can be waived only by a provision in the contract of sale, signed by both parties, that specifically waives the buyer's right to the test.

This is a summary of the county law, not legal advice; your attorney handles the contract terms, including any waiver.

The county's own private well program is slow for a sale. In most cases the county collects the sample within six weeks of receiving payment, results take at least eight weeks after that, and the department suggests a commercial laboratory for homes being resold. We collect the raw-water sample from a tap ahead of any treatment, the laboratory runs the panel for the county requirement, and we can add PFAS, 1,4-dioxane, or pesticides where the location warrants them. If the home has a treatment system, a second sample after treatment shows whether it is working. The sample can be collected during the home inspection visit.

What We Test Private Wells For

The panel depends on the property: its location, its history, and what is nearby. The core tests and the New York limits they are read against:

• Bacteria. Total coliform indicates the sanitary condition of the well; E. coli indicates fecal contamination. The New York State Department of Health recommends testing a private well for coliform bacteria at least once a year.

• Nitrate. The limit is 10 milligrams per liter as nitrogen. Suffolk County identifies nitrogen from cesspools and septic systems as the single largest cause of degraded water quality in the county. Those systems discharge to the same groundwater private wells draw from, which is why nitrate belongs on every well test here.

• Iron and manganese. The New York limit is 0.3 milligrams per liter for each, and 0.5 for both combined. Both cause staining and taste problems, and U.S. Geological Survey models predict manganese is more likely in Long Island's shallow upper glacial aquifer and along the south shore.

• Volatile organic compounds, including petroleum compounds and solvents.

• PFAS. New York's limit for public water systems is 10 parts per trillion each for PFOA and PFOS. The federal standard adopted in 2024 is 4 parts per trillion each; public systems do not have to meet it until 2029, EPA has proposed extending that to 2031, and the rule is under challenge in federal court. We compare private well results against both.

• 1,4-dioxane. New York's limit for public water systems is 1 part per billion.

• Pesticides, on properties that were once farmed. The county's 2015 water resources plan reports that 6.5% of East End private wells exceeded pesticide limits, which it attributes to past farming.

• Lead and copper, at the tap, where plumbing materials are the source.

PFAS in the Town of Southampton

PFAS have been found in private and public wells in the western part of the Town. The Air National Guard base at Gabreski Airport in Westhampton was declared a state Superfund site in 2016 for PFOS from the historic use of firefighting foam, after county sampling found contaminated private wells nearby, and the Hampton Bays Water District added carbon filtration after PFAS was detected in one of its well fields. SCWA reported in June 2025 that all of the treated water it supplies meets the federal PFOA and PFOS standards.

New York State's private well PFAS pilot, which opened in Suffolk County in August 2026, offers free PFAS testing to owners and renters of properties on private wells, and rebates for treatment or connection to public water where PFOA or PFOS is at or above 10 parts per trillion. The program is open to current owners and renters, its funding is limited, and it tests for PFAS only. For a sale, or for a complete panel, we collect the sample for a commercial laboratory.

Testing a Home on Public Water

On SCWA water, testing at the tap looks at what happens after the water reaches the home:

• Lead and copper from plumbing and fixtures. The federal lead-free requirement for pipe and solder dates to 1986, and older homes in and around the Village can have plumbing that predates it. A first-draw sample shows what sits in the plumbing overnight; a flushed sample reflects the supply.

• Treatment equipment such as softeners and filters, which can add problems of their own when they are not maintained.

• Homes that sit empty. Water that stands in the plumbing through the off-season should be flushed before the home is used; EPA recommends flushing after periods of disuse, and CDC notes that stagnant water can increase the risk of Legionella growth.

How Sampling Is Done and Results Are Read

Samples are collected in the laboratory's own bottles, with gloves, and kept cold under chain of custody. Well samples come from a raw-water tap ahead of any treatment; lead and copper samples come from the kitchen tap with the aerator left in place. Sampling on site takes 30 to 60 minutes. Bacteria results usually arrive within a few days of the laboratory receiving the samples; chemical results take longer, and PFAS and 1,4-dioxane take the longest.

We go through the results with you against the New York limits, explain what a non-detect or a flagged value means, and, where treatment is warranted, describe the treatment types that address the problem. Certified carbon, ion exchange, and reverse osmosis systems reduce PFAS when they are maintained. 1,4-dioxane is harder to treat: ordinary carbon filters remove little of it, home options are limited, and the long-term solution is connection to treated public water where a main is available. We sell no equipment.

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