Mold and moisture reference
Mold and moisture facts for NYC property owners.
Six sourced facts about the moisture conditions, housing context, and licensed remediation process that shape better property decisions.
How to use this page
Useful numbers need useful context.
Mold is not a one-number problem. A water event, humidity level, building condition, and the role of the professionals involved all affect the next sensible step. This page collects facts from public agencies and identifies exactly where each one comes from.
These figures are reference points, not a diagnosis or a substitute for an independent assessment. For a property-specific conversation, review how remediation is organized or book a service call with Mr. Mold Free Inc.
Hours matter after a leak.
The EPA says that if wet or damp materials are dried within 24 to 48 hours after a leak or spill, mold will not grow in most cases. It is guidance, not a guarantee, and the water source still needs to be corrected.
Source: U.S. Environmental Protection Agency, current guidanceA practical indoor humidity range.
The EPA recommends keeping indoor relative humidity below 60 percent when possible, with 30 to 50 percent as the ideal range. Condensation on windows, walls, or pipes is a cue to address moisture quickly.
Source: U.S. Environmental Protection Agency, current guidanceU.S. homes reported an outside leak.
In the 2019 American Housing Survey, 11.7 million of 124 million occupied households reported water leakage from outside the home. The same survey found 9.4 million households reporting a leak from inside the home.
Source: U.S. Census Bureau, 2019 American Housing Survey data, published 2022Renter-occupied homes in Queens.
New York City’s 2023 Housing and Vacancy Survey estimates 481,021 renter-occupied housing units in Queens. That scale makes clear communication among residents, owners, managers, assessors, and licensed remediation teams especially important.
Source: NYC Housing Preservation and Development, 2023 survey estimateNew York licensing has applied since 2016.
Since January 1, 2016, New York has required a valid state license for people who engage, advertise, or hold themselves out as mold assessors, remediation contractors, or abatement workers for the work they perform.
Source: New York State Department of Labor, current licensing FAQNYC selects this many buildings each year.
NYC’s Underlying Conditions Program selects about 50 to 100 residential buildings annually for action based in part on the number, severity, and reach of mold or water-leak violations. This is a city program figure, not a count of all mold conditions citywide.
Source: NYC Housing Preservation and Development, current program guidanceMethod and sources
Primary public sources, kept easy to check.
Each fact above links directly to the public agency source that supports it. We selected current government guidance and public survey or program materials, then kept the original reporting year visible where it matters.
- U.S. Environmental Protection Agency: A Brief Guide to Mold, Moisture and Your Home
- U.S. Census Bureau: 2019 American Housing Survey highlights, published 2022
- NYC Housing Preservation and Development: 2023 Housing and Vacancy Survey estimate
- New York State Department of Labor: Mold Frequently Asked Questions
- NYC Housing Preservation and Development: Underlying Conditions Program
Start with a clear conversation