637 St Marks Avenue

Brooklyn, NY

BBL 3-01219-0069BIN 3396300

Concern level4 of 4

Severe

0141 open class-C HPD violations (immediately hazardous) across 30 apartments
0236 of those issued in the last 3 years
0320 open rent-impairing violation(s)
041 active DOB violation(s)
05Tax lien sold at the city's lien sale — a sign of financial distress
061 DOB fine lost by default (unpaid)

How this is set: open hazardous violations measured against the building's size, then raised by strong distress signals — HPD's enforcement program, court harassment findings, recent evictions, unpaid DOB fines, open housing-court cases, and a sold tax lien. Neighborhood noise and crime are not part of it. It describes the public record, not the condition of any one apartment, and a quiet record is not proof of a good building.

Rent regulation

Likely rent-stabilized

The owner registered 15 stabilized units with New York State for 2023 — of about 30 apartments.

2018 — 30 units registered2023 — 15

No public data says which specific apartment is stabilized.

Registration counts apply to the building, not to unit numbers. To confirm your own apartment, request your rent history from New York State Homes and Community Renewal — it is free and takes a few weeks.

How to request your rent history →

Rent regulation

The building

1900

Built

Floors

Residential units

Walk-up apartments

Type

The building

This building and the landlord's others

This building12 others linked to the same owner

HPD housing-maintenance violations

158

Open now

450

On record

Open Class C

Open Class B

Open Class A

Class C is immediately hazardous, Class B is hazardous, Class A is non-hazardous. A violation stays open until HPD certifies the repair, so some open items may already be fixed.

CLASS I · NON-HAZARDOUS

§27-2107 ADM CODE OWNER FAILED TO FILE A VALID REGISTRATION STATEMENT WITH THE DEPARTMENT AS REQUIRED BY ADM CODE §27-2097 AND IS THEREFORE SUBJECT TO CIVIL PENALTIES, PROHIBITED FROM CERTIFYING VIOLATIONS, AND DENIED THE RIGHT TO RECOVER POSSESSION OF PREMISES FOR NONPAYMENT OF RENT UNTIL A VALID REGISTRATION STATEMENT IS FILED.

Status: Notice issued, not yet certified

CLASS I · NON-HAZARDOUS

Status: Notice issued, not yet certified

CLASS C · IMMEDIATELY HAZARDOUSIssued 2026-07-24

§ 27-2033 ADM CODE PROVIDE READY ACCESS TO BUILDINGS HEATING SYSTEM LOCKED DOOR AT BASEMENT AT BOILER ROOM

Status: Notice issued, not yet certified

CLASS C · IMMEDIATELY HAZARDOUSApt 4DIssued 2026-07-24RENT-IMPAIRING

§ 27-2031 ADM CODE PROVIDE HOT WATER AT ALL HOT WATER FIXTURES IN THE ENTIRE APARTMENT LOCATED AT APT 4D, 4th STORY, 2nd APARTMENT FROM NORTH AT EAST , SECTION AT WEST

Status: Notice issued, not yet certified

HPD housing-maintenance violations

311 complaints from tenants

331

All time

Last 12 months

Heat/Hot Water132

Unsanitary Condition39

Plumbing29

Water Leak28

Electric27

General26

Paint/Plaster15

Door/Window13

Complaints record what a tenant reported, not a finding by the city. "Closed" often means the inspector could not gain access.

311 complaints from tenants

Neighborhood noise

Higher than averagevs. NYC apartment blocks

895

Noise reports · last 12 mo

≈ per month

% from neighbors

Residential380

Street/Sidewalk220

Commercial149

Unspecified72

Vehicle37

Helicopter35

House of Worship2

311 noise complaints within about 1,000 ft (a few blocks) in the last year. Most reports here are about outdoor noise (mostly residential) — street life and traffic more than neighbors. This counts how often people call 311, which tracks how densely populated and busy an area is as much as how loud it is — it is not a sound measurement.

Neighborhood noise

Neighborhood crime

About averagevs. NYC apartment blocks

225

NYPD reports · last 12 mo

≈ per month

Felony81

Misdemeanor93

Violation51

NYPD complaints reported within about 1,000 ft (a few blocks) in the last year, by severity. This reflects what gets reported and where police are active as much as actual safety, and busier, denser, higher-foot-traffic blocks log more. Locations are approximate — the NYPD shifts each report to the nearest corner for privacy — so read this as rough context, not a safety score.

Neighborhood crime

Bedbug history

No bedbugs reported

The owner filed 8 annual bedbug reports and reported no infested units. Filing with zero infestations is the compliant, reassuring case.

Bedbug history

DOB building violations

Active

On record

Active, last 3 yrs

ACTIVE · C-CONSTRUCTION OTHER OPTIONAL2024-04-24

ATOI, OBSERVED AT EXPO 1, 60+ FOOT ROOF SOFFIT CRACKED WITH HOLES, UNSUPPORTED & LOOSE PARAPET BRICKS AT BOTH SIDES, 3RD FLOOR WINDOW HAS CRACKS IN THE WINDOWSILL. LOOSE STONE AT ENTRANCE FACADE ABOVE 641 ADDRESS.

DOB building violations

Evictions

No executed evictions on record for this building.

Evictions

Housing court

Cases on record

Open now

Tenant-brought

Harassment found

With a judgment

Most cases are tenants taking the owner to court to force repairs. A case is not proof of wrongdoing; a harassment finding or judgment is a court ruling against the owner.

CLOSEDOpened 2026-09-29

Heat / hot water

CLOSEDOpened 2026-09-11

Tenant action

CLOSEDOpened 2025-02-13

Tenant action

CLOSEDJUDGMENTOpened 2024-04-01

Heat / hot water

Housing court

Landlord and related buildings

Registered owner

PROSPECT HEIGHTS 637-641 REALTY LLC

Head officer

JOE PATRICKOWSKI

Managing agent

WATERSTONE GROUP LLC

12 other buildings share this owner's registration contacts. Shared contacts suggest common control, but they are not proof of ownership.

1155 EAST 35 STREETBROOKLYN 1408 EAST 13 STREETBROOKLYN 1479 EAST 34 STREETBROOKLYN 1487 EAST 34 STREETBROOKLYN 24 ROGERS AVENUEBROOKLYN

Landlord and related buildings

Unpaid city fines

$9,100

Balance due (active)

Active violations

Lost by default

DOB violations adjudicated by OATH carry money penalties. "Lost by default" means the owner never appeared at the hearing. An unpaid balance is a stronger "ignoring the city" signal than a raw violation count.

DEFAULTConstructionClass 22026-05-06$6,250 due

UnknownClass 22024-09-13$800 due

UnknownClass 22024-05-01$800 due

ConstructionClass 12024-04-24$1,250 due

Unpaid city fines

Ownership & money

Speculation watch

·Bought and resold within a few years — rapid turnover is a common speculation signal

A pattern, not a prediction — many transfers are ordinary or between related companies.

Recorded sales

Mortgages / refinances

Last recorded sale2022-05-09 · no recorded price

Most recent mortgage2022-05-09 · $8,200,000

Mortgage2022-05-09$8,200,000

borrower PROSPECT BROOKLYN REALTY LLC · lender POPULAR BANK

Sale2022-05-09no recorded price

PROSPECT BROOKLYN REALTY LLC → PROSPECT HEIGHTS 637-641 REALTY LLC

Mortgage2018-04-16$2,100,000

borrower PROSPECT BROOKLYN REALTY LLC · lender POPULAR BANK

Mortgage2016-11-09$2,640,000

borrower PROSPECT BROOKLYN REALTY LLC · lender BANCO POPULAR NORTH AMERICA

Mortgage2016-07-07$2,962,673

borrower PROSPECT BROOKLYN REALTY LLC · lender TBG FUNDING LLC

From ACRIS recorded documents. Amounts are often $0 or nominal for transfers between related parties, and LLCs can obscure who is really involved — treat this as public-record context, not a valuation.

Ownership & money

City debt & tax-lien sale

The lien was sold in the 2025 tax-lien sale

The owner's unpaid water and sewer charges went unresolved through a series of notices, and the debt reached the city's Final Sale list — the lien was sold to a private collector who can add interest and fees.

Years listed

2025

Most recent

Final salewater/sewer only2025-06-01

10-day noticewater/sewer only2025-05-01

30-day noticewater/sewer only2025-04-01

60-day noticewater/sewer only2025-03-01

From DOF lien-sale lists (2019–2025). Financial distress is not proof of neglect, but owners behind on what they owe the city more often let repairs slide. Debt may since have been paid.

City debt & tax-lien sale