Most Park Slope multifamily buildings never touched rent stabilization. Not because an owner fought it off, not because of a tax abatement quirk, but because of a number written into state law decades ago: six units. Park Slope's classic stock, the three-story brownstone with a parlor duplex over one or two rental floors, almost never reaches that threshold. For as long as anyone buying one of these buildings has been alive, that has meant full discretion. Set the rent the market will bear, decline to renew a lease at the end of its term, no explanation required.
That discretion changed on April 20, 2024, when New York's Good Cause Eviction law took effect automatically across New York City. It does not turn a three-family brownstone into a rent-stabilized building. But for most owners of that exact building type, it does something adjacent: it requires a recognized reason to end a tenancy and it puts a ceiling on what counts as a reasonable renewal increase. If you're underwriting a Park Slope multifamily purchase, or pricing one to sell, the gap between "never regulated" and "not regulated the way you assumed" is exactly where the surprises live.
The Building Type That Was Built to Sit Outside Rent Stabilization
Rent stabilization in New York generally applies to buildings with six or more units constructed before 1974, a rule the NYC Mayor's Public Engagement Unit and the Rent Guidelines Board both confirm. Park Slope has plenty of buildings on the wrong side of that line for tenants and the right side for owners: two-family, three-family, and four-family brownstones, often a parlor-floor duplex sitting above one or two rental units, are the neighborhood's most common income-producing property type. They sit below the six-unit threshold, which has meant they sit outside rent stabilization entirely.
The neighborhood also has the other kind of building: prewar elevator apartment houses with six or more units, some of them already carrying rent-stabilized leases that predate any current owner. Those two building types have operated under genuinely different rules for decades. A buyer comparing a small brownstone to a stabilized walk-up wasn't comparing two flavors of the same asset. They were comparing an asset with full rent and renewal discretion to one governed by the Rent Guidelines Board's annual increase caps.
That distinction is why small multifamily brownstones became a favorite entry point for Brooklyn investors and owner-occupants who wanted rental income without a regulated ceiling on it. It is also exactly the assumption Good Cause Eviction disturbs.
What Changed on April 20, 2024
Good Cause Eviction does not touch cooperatives, condominiums, or apartments already under rent stabilization or rent control, according to both the New York Attorney General's publication on the law and the city's own guidance. What it does cover is unregulated, market-rate rentals, occupied as a primary residence, in New York City or in a municipality that has opted in. For a covered unit, a landlord can no longer decline to renew a lease simply because the term is up. They need one of the law's recognized grounds: nonpayment, a substantial lease violation, nuisance, illegal use, denial of access, or the landlord's own good-faith intent to occupy the unit.
The law also sets a rent-increase benchmark. Each year, New York publishes a "local rent standard," the rate of inflation plus five percentage points, capped at ten percent. As of the May 2026 update from Homes and Community Renewal, that standard sits at 8.38%. A renewal increase above that figure on a covered unit is presumptively unreasonable, meaning a tenant can raise it as a defense in Housing Court, though a landlord can still argue for a larger increase based on documented costs like repairs or property tax increases.
Here is the detail that surprises most owners who assume Good Cause simply imported rent stabilization into their building: it did not. The Rent Guidelines Board's cap for stabilized renewals this cycle is 3% on a one-year lease and 4.5% on a two-year lease. Good Cause's 8.38% ceiling for market-rate units is nearly double the stabilized rate. The two systems look similar from a distance, a good-faith reason to evict, an annual cap on increases, but they are not the same system, and the newer one leaves considerably more room.
Good Cause did not turn Park Slope's brownstones into rent-stabilized buildings. It gave them a different ceiling, one that is real, but higher than the one stabilized buildings answer to.
The Exemption That Still Matters: Are You a Small Landlord?
The law carves out an exemption for small landlords, defined as an individual who owns ten units or fewer across all of New York State. If a building is owned through an LLC with multiple members, each individual owner must independently fall at or under that ten-unit count for the exemption to apply. Own a three-family brownstone and nothing else in the state, and you're almost certainly exempt. Own that same three-family building plus a handful of other small multifamily properties picked up over the years, and the aggregate count across every property you touch is what determines coverage, not the unit count of any single address.
Owner profile | Rent stabilized? | Covered by Good Cause? | Why |
|---|---|---|---|
Owner's only NYS property is a 3-family brownstone | No, under 6-unit threshold | Likely exempt | Small landlord, 10 units or fewer statewide |
Owner holds six 3-family brownstones across Brooklyn | No, under 6-unit threshold per building | Likely covered | Aggregate ownership exceeds 10 units statewide |
8-unit prewar walk-up built in 1925 | Yes | Not applicable | Rent stabilization already governs the building |
A unit renting above 245% of the area's Fair Market Rent | No | Exempt | High-rent carve-out applies unit by unit |
A separate exemption exists for owner-occupied buildings of ten units or fewer where the owner actually lives on site, which covers a meaningful share of Park Slope's classic owner-duplex-plus-rental configuration even when the math on statewide unit count gets close.
The High-Rent Exemption Investors Miss
Good Cause also exempts units renting above 245% of the area's Fair Market Rent, a figure the Department of Housing and Urban Development sets and that Homes and Community Renewal is required to publish by county each year, on or before August 1. This exemption runs unit by unit, not building by building. A three-family brownstone can have one top-floor unit renting comfortably above that threshold, exempt, sitting next to a garden unit renting below it, fully covered. Two apartments in the same building, two different sets of rules, and a buyer who treats the whole property as one regulatory category is going to misjudge at least one lease.
What This Changes for Underwriting and Diligence
None of this makes small multifamily brownstones a bad investment in Park Slope. It changes what discipline looks like when you buy or sell one.
For a buyer, a business plan that assumes you can simply decline to renew a tenant's lease after closing needs a second look. If the unit is covered and the tenant pays on time and follows the lease, "I'd like to renovate" is not on the law's list of recognized grounds unless you can show a documented good-faith plan to occupy the unit yourself. Since August 18, 2024, landlords have also been required to give tenants written notice of whether Good Cause applies to their unit, at lease signing, at renewal, or before certain actions like a rent increase over 5% or a non-renewal. If a seller never issued that notice, the gap doesn't disappear at closing. It becomes the new owner's problem the first time an eviction ends up in Housing Court.
The enforcement climate around this law is also more active than it was even a year ago. Mayor Zohran Mamdani's Executive Order 03, signed January 1, 2026, revitalized the city's Office to Protect Tenants under director Cea Weaver, and a companion order sent that office into borough-wide public hearings on landlord practices earlier this year. Tenants have heard more about these protections in 2026 than they did when the law was new, which means the paperwork trail matters more, not less.
Before you close on a small Park Slope multifamily building, get clear answers on the following:
- How many residential units does the seller, and any co-owners, hold across New York State, counting every LLC they're part of.
- Whether a Good Cause notice was issued to each current tenant, and whether the seller can produce it.
- Whether any unit's rent already sits above 245% of the published Fair Market Rent for its size and county.
- What specific grounds you or the seller would actually rely on to end a tenancy, and whether your renovation or repositioning plan matches one of the law's recognized reasons.
- Whether your own total New York State unit count, after this purchase, still keeps you inside or pushes you outside the small landlord exemption.
Frequently Asked Questions
Does Good Cause Eviction apply to co-ops or condos in Park Slope? No. Cooperative and condominium units are exempt from the law regardless of building size.
If I buy an exempt building, does the exemption transfer with the sale? Not automatically. The small landlord exemption is based on the owner's total statewide unit count at the time of an eviction case, so your own portfolio, not the seller's, is what a court will look at after closing.
Does an owner-occupied three-family building need a Good Cause notice for the rental units? Generally yes, unless the building qualifies for the small landlord or owner-occupied exemption outright. Confirm which exemption applies and document it, since the burden falls on the landlord to show it in court if a tenant challenges an eviction.
Buying or selling a small multifamily building in Park Slope now involves a regulatory layer that didn't exist two years ago, and getting the unit count, the notices, and the rent math right before you sign anything is worth more than a quick read of a listing sheet. If you're weighing a purchase, a sale, or just want a straight answer on where your property actually stands, the Peter Mancini Team can walk through your specific building with you. Get Your Home Valuation and start with the numbers that actually apply to you.
