Well water testing in Suffolk County, New York (2026)

WellTestList · Sunday, October 25, 2026 · county page · back to the New York page

Suffolk County has an estimated 70,000 households on private wells by EPA’s 2020 model, more than any other county in New York. The county health department puts its own count at 40,000 to 45,000 wells serving over 200,000 people, mostly on the East End and in Brookhaven. Every one of them draws from a shallow sole-source aquifer, and Suffolk is one of the few places in the country where you must have a lab test the well before you buy the house. Here is the county’s own testing program, what it costs, the local labs, and what Long Island groundwater calls for.

The short version

1. The county will test your well for $100. The Suffolk County Department of Health Services (SCDHS) private well program sends staff to sample and runs bacteria, inorganic chemicals, VOCs and petroleum compounds, plus carbamate pesticides in farm areas. It’s $350 if the well never got final approval or the house has no valid certificate of occupancy. Expect a visit within about 6 weeks and results by mail about 8 weeks after that.
2. Buying a house with a well? The county requires a lab test before closing. Suffolk County Code Chapter 840 says the buyer must get a certification from a New York State approved lab that the raw water meets SCDHS new-construction standards. It can only be waived in the signed contract.
3. Don’t count on the county program for a closing. SCDHS itself says to use a commercial lab for a resale, because its results may not arrive in time.
4. PFAS testing is free right now. The New York State private well PFAS pilot covers Suffolk. If PFOA or PFOS comes back at 10 ng/L or higher, the state offers rebates for treatment or a public-water hookup.
5. New wells have a set test list. The county standards list 66 parameters (bacteria, nitrate, metals, and dozens of VOCs including MTBE) on untreated water, at a state-approved lab, before final approval.
6. Test bacteria every year, and the wider chemistry every 3 to 5 years. That’s the New York State Department of Health’s advice. On Long Island, include nitrate and VOCs.

Who to call

• SCDHS Bureau of Drinking Water: (631) 852-5810. It runs the private well water testing program, approves new wells, and answers questions about results. Offices are at the H. Lee Dennison Building, 100 Veterans Memorial Hwy, Hauppauge, and the Riverhead County Center, County Road 51, Riverhead.
• PFAS pilot help line: 800-616-9275 or PrivateWellPFAS@hrpassociates.com, per the state’s Suffolk flyer.
• Renting? SCDHS notes that a landlord may be responsible for the water supplied to tenants.

The SCDHS program, step by step

• Fee: $100 for an existing well the department previously approved, or one serving a house with a valid certificate of occupancy. $350 for new construction, a well without final approval, or a house without a valid CO. Households with income under $25,000 can ask for a fee exemption with a notarized form. There’s no fee for an aldicarb (Temik)-only test in farm areas where Temik was used.
• How to request: mail the request form, including your tax map number, with a check payable to “Suffolk County Department of Health Services.” The form asks for your doctor’s name.
• Sampling: department staff collect the sample. You can’t drop off your own bottle. An outside tap is fine, so you don’t have to be home.
• Limits: only the primary drinking-water well is tested (not irrigation wells), and the county may limit how often one well is tested.
• Privacy: SCDHS says results may be released under New York’s Freedom of Information Law.
• The lab behind it: the Suffolk County Public and Environmental Health Laboratory in Hauppauge (ELAP ID 10528), which is also on the state’s list of labs accredited for PFAS testing.

The county’s 2015 water resources plan called the $100 fee “much lower than the cost of analyses performed by commercial laboratory testing.” It also found fewer than 600 owners a year were using it, under 1% of the county’s wells.

ELAP-certified labs in Suffolk County

New York requires a lab certified by the state’s Environmental Laboratory Approval Program (ELAP) for any result you’ll hand to a buyer, lender, or the county. We checked tonight for in-county labs that take homeowner samples and post prices. None of the commercial labs post homeowner prices, so call for a quote.

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The Suffolk County Water Authority lab in Hauppauge (ELAP 10311) is a utility lab for public water and isn’t a homeowner drop-off. Other Long Island labs appear on third-party lists, but we couldn’t confirm their certifications or prices tonight, so they’re not listed. New York’s online ELAP lab search was down when we checked. We leave out any lab that sells water treatment or belongs to a pump or treatment company.

What’s in Suffolk County groundwater

• Nitrate. It comes mostly from cesspools, septic systems, and fertilizer. Nitrate was over the 10 mg/L drinking-water standard in about 7% of the private wells SCDHS sampled from 2007 to 2013 (Comprehensive Water Resources Management Plan, 2015, section 4). The plan notes that private wells here are typically screened only about 40 feet into the water table, which makes them very susceptible to what happens at the surface.
• VOCs. Solvents and fuel compounds were over the 5 µg/L threshold in 19% of the private wells SCDHS sampled from 1997 to 2013 (same plan). That’s why the county program, and the new-well list, include a long VOC panel. Most basic mail-in kits don’t.
• Pesticides on the East End. In 834 private and non-community wells SCDHS sampled with the state DEC in 2000–01, pesticide compounds or their breakdown products turned up in 50.6%, and a pesticide drinking-water standard was exceeded in 6.5% (NYSDEC Long Island pesticide data, 2014). Aldicarb (Temik), once used on potato fields, is the best-known example. SCDHS tests carbamate pesticides in farm areas and may add aldicarb or dacthal to a new-well test.
• PFAS and 1,4-dioxane. New York’s drinking-water limits are 10 ppt each for PFOA and PFOS and 1 ppb for 1,4-dioxane. New York was the first state to set a 1,4-dioxane limit (NYSDOH; SCDHS emerging contaminants). Those limits legally apply to public water, but they’re the numbers the county and the PFAS pilot use. SCDHS has investigated PFAS in groundwater near the Air National Guard base in Westhampton and in Yaphank (SCDHS water facts). See our PFAS Method 533 / 537.1 guide.
• Salt water. Near the shore, wells can hit the saltwater interface. The county standards allow shallower screens there, and chloride over 250 mg/L is on the county’s treatment table.

Free PFAS testing: the state pilot

The NYSDOH private well PFAS pilot is taking testing applications from Suffolk, Dutchess, Orange, Putnam, Ulster, and Westchester. The state may pause applications while it tracks funds. Testing is free using EPA Method 537.1 v2, and results take about 2 to 6 weeks after sampling. If PFOA or PFOS is 10 ng/L or higher, the pilot offers rebates of up to $5,000 for whole-house treatment, $1,000 for a single-tap system when whole-house isn’t feasible, or $10,000 to connect to public water. SCDHS private well results dated January 1, 2025 or later can also qualify you for a rebate. The follow-up test after treatment must use Method 533 or 537.1 v2 at a New York-accredited lab. Find your own installer. Don’t buy from anyone who shows up offering to “qualify” you.

New wells and home sales

New wells. The SCDHS Standards for Private Water Systems (issued under Sanitary Code Article 4, §406.4, revised through July 1992 per its cover, and still the version the county posts) require approval before you build a well. If a public water main is close enough, you have to connect instead. For a single-family house, that means a main within 150 feet of the property line, or within 250 feet if the well can’t meet the separation or depth rules or the untreated water fails. New wells must be at least 50 feet deep, screened at least 40 feet below the water table, and at least 150 feet from leaching pools. Before final approval, the water must be tested at the owner’s cost by a New York State approved lab, on raw untreated water, for the 66 parameters in the standards’ Table 5. Those are total coliform, pH, conductivity, nitrate, ammonia, chloride, iron, manganese, zinc, copper, lead, MBAS (detergents), and a long VOC list including MTBE. The department may add aldicarb or dacthal. Results must be less than a year old. Treatment is only allowed when deepening or moving the well won’t work, and it needs a covenant filed with the County Clerk.

Buying a house. Under Suffolk County Code §840-3 (Local Law 7-2000, amended later in 2000), no purchase of a house served by a private well can close until the buyer has a written certification from a New York State approved lab. The certification has to show that the untreated water meets SCDHS standards for new residential construction, and buyer and seller exchange it at closing. If the water fails, the buyer must tell the seller within 15 days. The seller then fixes it or cancels and returns the down payment, unless the buyer agrees in writing to go ahead anyway. The test can be waived only by a clause in the signed contract (§840-4), and the rule doesn’t apply to gifts or transfers by operation of law. Because the county program is slow, plan on a commercial ELAP lab. More detail is on our home purchase / lender page.

Mail-in kits that email a PDF

For routine testing between county visits, independent mail-in labs ship to Long Island. Listed prices checked October 25, 2026:

• Tap Score / SimpleLab Essential Well: $209. It covers metals, minerals, nitrate and nitrite, and coliform bacteria including E. coli. It doesn’t test VOCs.
• Tap Score / SimpleLab Advanced Well: $399. It adds VOCs and common petroleum compounds and includes overnight shipping to the lab. It’s the closer match for Suffolk’s VOC problem.
• National Testing Laboratories WaterCheck Basic: $220. It covers bacteria, 22 metals and minerals, and 7 inorganic chemicals. Next-day return shipping isn’t included, so budget for it on the bacteria bottle.

All of these cost more than the county’s $100 visit, which also covers VOCs. Mail-in kits make sense when you want a result in weeks, not months. Don’t use one for the Chapter 840 sale certification or a new-well approval unless you’ve confirmed that the lab is New York ELAP-certified for every required parameter. For a sale, a local ELAP lab that samples on site is the safe choice. None of these kits covers PFAS. Use the free state pilot for that.

Side by side for a Suffolk County well

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Related: New York well testing · Worcester County, MA · Fairfield County, CT · Rockingham County, NH · Chester County, PA · Oakland County, MI · How to read a well water report · PFAS 533 / 537.1 · Home purchase / lender · back to the directory.