Buying a business in Suffolk County, New York

The size of the market, in numbers

Suffolk and Nassau are usually described as one market. On the measures that decide whether you can buy something, they are not.

About these figures. Establishment counts and size bands come from Census County Business Patterns for 2023 ^[1] ; wages come from the BLS Quarterly Census of Employment and Wages for 2024 ^[2] . The two series count slightly differently — CBP counts establishments with paid employees in a March reference period, QCEW counts covered employment across the year — so their establishment totals do not match, and we show each for what it measures rather than blending them. Both are published as an open dataset on our New York market data page, where you can compare any county to any other.

The band you can actually buy

Establishment counts flatter every market. The distribution is the useful part.

9,014 Suffolk establishments sit in the 10–49 employee range, against 7,811 in Nassau. If your criteria require a business with staff who can run it without you, Suffolk is the deeper of the two counties — which is the opposite of what its more rural reputation suggests.

The usual cautions: these are establishments rather than firms, so multi-site operators are counted more than once, and an establishment existing does not make it available.

Seasonality is the whole underwriting question

This is the single most important thing to understand before pricing a Suffolk business. Nassau-Suffolk leisure and hospitality employment ^[4] :

That is a metro-wide figure, and the East End concentration is sharper still. Three consequences for a buyer:

1. A trailing-twelve-month number tells you almost nothing on its own. Ask for monthly revenue, monthly payroll and monthly card settlement for 36 months. If the seller cannot produce them, that is your answer about the books.
2. Working capital is not optional. A seasonal business must carry fixed costs through the quiet half of the year. A buyer who spends every dollar on the injection and closing costs has bought a business they cannot operate in February. Size the requirement with the working capital calculator.
3. Debt service is tested against the trough, not the mean. Run the DSCR calculator on your worst quarter annualised as well as on the year. If only the annual figure works, the deal is thinner than it looks.

The corollary is that seasonality is also an opportunity: it is systematically mispriced by buyers who only look at annual totals, and a buyer who underwrites the trough properly can be confident where others are guessing.

Labour and wages

Average annual pay in Suffolk’s private sector is $75,653, or $1,455 a week ^[2] — within $500 of Nassau, so the two counties are not meaningfully different on cost of labour. What differs is availability: Suffolk's workforce is spread over a much longer geography, and seasonal employers compete for the same summer staff.

Across the metro division, education and health services (322.9 thousand jobs) and trade, transportation and utilities (251.1 thousand) dominate, with professional and business services (192.0 thousand) the only supersector growing meaningfully year over year ^[4] . Construction runs 83.6 thousand and is negative year over year — relevant if you are buying a home-services business whose demand assumptions were set in a stronger market.

Use the county average, not the seller's own draw, when you test the owner-compensation add-back. Our SDE guide explains why, and the owner earnings calculator does the arithmetic.

Suffolk is several markets

Tax

Publication 718, effective 1 March 2025, puts Suffolk at 8¾% (8.75%), against Nassau's 8.625% ^[3] . Both include the 3/8% MCTD component. Verify the jurisdiction using the Department's Sales Tax Jurisdiction and Rate Lookup Service rather than by ZIP code — Publication 718 warns that ZIP-based lookups produce "a high degree of inaccurate tax reporting."

No New York City taxes apply: no Business Corporation Tax, no Unincorporated Business Tax, no Commercial Rent Tax. Property taxes are high and reach you through the rent. The state bulk-sale process applies at closing — notify at least 10 days before taking possession or risk inheriting the seller's unpaid sales tax ^[5] . See the bulk-sale guide.

The aquifer rule, and the word that decides whether it bites

Suffolk sits on what Article 6 of its Sanitary Code calls Long Island's "Federally-designated sole source aquifer", and the county regulates sewage disposal accordingly ^[8] . For a buyer the whole question is whether a purchase pulls you into that regime, and the answer turns on one word.

The trigger is a change of use, not a change of ownership. Article 6 defines a "New Other Construction Project" to include "the change of use of an Other Construction Project which requires the installation of new Sewage disposal facilities or increased capacity of the existing Sewage disposal facilities" ^[8] . Section 760-604 then prohibits engaging in one without prior Department approval of the water supply and sewage disposal facilities.

What happens once you are in the process

This is the part that costs money. Section 760-613 provides that where an application is made for approval, an I/A OWTS — an innovative and alternative onsite wastewater treatment system, meaning nitrogen-reducing treatment rather than a conventional septic arrangement — shall be required as the method of sewage disposal for a project that existed before 1 January 2018, where the section's conditions are met ^[8] .

Those conditions turn on the density load established by any previous approval, whether the structure is habitable under current building codes, and which Groundwater Management Zone the site falls in — Zones III, V and VI are treated differently from the rest of the county.

The practical consequence: a conversion that looked like a fit-out budget can acquire a wastewater capital cost, and it surfaces at the approval stage rather than at the LOI. On a site where the existing system predates 2018, that is a question to answer before you price the deal.

What to do about it

1. Establish the approved use and the approved density load for the site, from the Department's own records rather than the seller's account of them.
2. If you intend any change of use or expansion, get a design professional in early. Whether it requires new or increased sewage capacity is an engineering question, and it determines whether you are in the regime at all.
3. Find out which Groundwater Management Zone the site is in. It changes the test under §760-613.
4. Price an I/A OWTS as a contingency on any pre-2018 site where a change of use is part of your plan. If it turns out not to be required, you have a better deal than you underwrote.
5. Make approval a closing condition where the business case depends on the change of use. Closing first and applying afterwards puts the risk entirely on you.

Scope note. This is Article 6 only. Article 19, the Department's residential and commercial construction standards, the I/A OWTS approval list and any applicable State Pollutant Discharge Elimination System permit all sit alongside it, and a sewage treatment plant serving a larger site is a different regime again. Treat the above as the map, and take the specific question to counsel and a design professional.

Suffolk-specific diligence

• 36 months of monthly figures, before anything else. In a seasonal market this is the diligence — run them through the seasonality stress test to find the trough and the cash low point.
• A working-capital target that survives February, not one calculated on an annual average.
• Summer staffing plan and cost. Ask who the seller hires, from where, at what rate, and whether housing is part of it.
• Lease term against season. An East End lease that expires in March is a very different asset from one that expires in October.
• Water and wastewater. Suffolk sits on a sole-source aquifer and county sanitary rules govern discharge and septic systems. For any food service, laundry, car wash or vehicle-service target, confirm the existing approvals and whether a change of ownership triggers review before you sign. This is a county-administered regime and we have not yet published a sourced guide to it — treat it as a specialist question for counsel.
• Sales-tax filings reconciled to revenue at 8.75% ^[3] , and the bulk-sale notice filed on time ^[5] .
• Workers' compensation, disability and Paid Family Leave coverage from day one ^[6] ; UI registration via the NYS 100 ^[7] .
• Town and village permitting. Suffolk has ten towns and dozens of villages with materially different rules on signage, hours, outdoor seating and short-term rental. Verify locally, not at county level.
• Trade licensing. Suffolk Consumer Affairs licenses over 15,000 vendors across 28 categories, and over half of all licences issued or renewed each year are home improvement licences — a definition that catches landscapers, tree services, exterminators, pool and driveway contractors. The county states that unlicensed contractors are subject to arrest and prosecution. The downstate licensing guide covers what transfers and what does not.

Where else to look

Nassau is the same size with a thinner mid-band, slightly lower sales tax and less seasonality. The Long Island regional guide covers both counties together. The Hudson Valley offers a comparable mix of commuter and seasonal markets at lower entry prices. The data page compares all 62 counties on the same measures.