Black Mold in an NYC Apartment: What Should You Do?

Photograph the patch from where you stand, with a ruler in the frame for scale, and tell your landlord in writing the same day. Then measure how much of the room it covers, because New York City grades a mold violation by square footage in a single room, not by the color of the growth.

A dated record and a number are what the first 48 hours are for. The class an inspector writes, and the deadline your landlord gets, follow from the area and the water behind it.

Black Mold and What Color Tells You

The New York City Health Department describes mold as coming in gray, black, green, yellow and orange. Color describes it, it does not identify it. Stachybotrys chartarum, the species most people mean by black mold, is what the CDC calls a greenish-black mold, and other molds look much the same on a wall.

The CDC is blunt about identification: there is no need to determine what type of mold is growing in a home, and all molds should be treated the same for health risk and removal. On the claims that circulate about Stachybotrys, the agency says no test proves an association between it and particular symptoms, and that the suggested link to acute idiopathic pulmonary hemorrhage in infants is unproven.

Mold exposure can cause or worsen asthma symptoms and allergies such as hay fever, with congestion, a runny nose, coughing and trouble breathing in people sensitive to it. Severe reactions concentrate among immune-compromised people, people with chronic lung disease, and people undergoing transplants or chemotherapy. Symptoms usually clear once the mold is gone.

Visible Mold Violations Under Section 27-2017.3

Section 27-2017.3 of the Housing Maintenance Code makes visible mold in any room of an apartment in a building with three or more apartments a violation in its own right. Three tiers sit inside it, set by the square feet covered in that room. Mold on tile or grout is excluded, which puts much shower growth outside the section.

The 21 days is the mold-specific rule in 27-2017.3(c)(2), longer than the 24 hours most immediately hazardous conditions carry. The 90 and 30-day periods come from section 27-2115(c), the schedule governing every other class of HPD violation.

Class Escalation After a Missed or False Certification

The square footage is not the strongest part of the section. A Class A mold violation becomes a Class B one if the certification period runs out uncertified and the same mold is still in that room, or if the owner filed a false certification and the mold is still there. A Class B violation climbs to Class C on both routes. On the expired-certification route the code requires HPD to reinspect within 70 days of the certification date and find the condition unchanged; on the false-certification route it does not.

An owner who signs off work that nobody did ends up worse off than one who says nothing. HPD closes the original violation and reissues it at the higher class, and where the Class C came out of a reinspection, the code bars any postponement of the new deadline.

HPD's Local Law 55 report for fiscal 2025, the year to June 2025, counts 41,345 mold violations issued, of which 13,768 were upgrades rather than first findings. About one in three. The report puts the share certified as corrected at around 23% and records 504 false mold certifications. HPD attempts to reinspect every Class B and Class C mold violation whether or not the owner certified it, which drives the owner-side procedure for clearing a mold violation properly.

Reporting Mold to Your Landlord and 311

HPD tells tenants to notify the landlord on seeing a leak or signs of mold, and to file with 311 if the landlord does not fix it or if the repair work is being done unsafely. Housing Court Answers, the nonprofit staffing the tables in the city's housing courts, tells tenants to write to the landlord listing the repairs they need, send it by certified mail, and call 311.

Asking has force of its own. Under 27-2017.2(b) the owner must investigate for indoor allergen hazards at least once a year, and again whenever a tenant complains about a condition likely to cause one or asks for an inspection. A written request triggers that duty with no 311 complaint needed, and the complaint is what gets HPD into the apartment.

If you or your child has moderate or severe persistent asthma, your doctor can request a free home environmental inspection through the Health Department's Online Registry.

What HPD Does on a Mold Inspection

Section 27-2017.6 gives HPD 30 days from your complaint to inspect, and 10 further days to serve the notice of violation. Between October 1 and May 31 HPD may extend that window, and a deadline it misses does not void a violation it later writes.

HPD need only inspect the parts of the apartment where furniture does not block the view of a surface, unless visible evidence suggests the hidden surface has mold. The code's definition of visible mold does cover growth behind furniture, so pulling a bookcase off the wall before the appointment changes what can be written up.

HPD received 38,278 mold complaints in fiscal 2025 and attempted 53,101 inspections, completing 32,644. When an owner certifies a correction, HPD mails you a notice and asks you to contact the agency if the condition is still there. A landlord who keeps ignoring mold after a violation issues is a different problem from one who has not been told.

Unsafe Cleanup Methods

Painting over mold is the most common mistake: the EPA says not to paint or caulk moldy surfaces, because paint over mold is likely to peel. Chlorine bleach is the next. The EPA does not recommend a biocide such as chlorine bleach as a routine practice during mold cleanup, and the city's own method uses soap or detergent and water. The CDC does list a dilute bleach solution for hard surfaces, and warns never to mix bleach with ammonia, which produces a poisonous gas.

Scrubbing a soaked porous surface as though it were tile is the third. Absorbent materials such as ceiling tiles and carpet may have to be thrown out once moldy, because mold gets into the material rather than sitting on it, and the city's work practices say to discard what cannot be cleaned.

For a small patch on a hard surface the Health Department's method is soap or dish detergent and water, waterproof gloves, children and pets kept away until the area is clean, and the surface dried completely. The EPA's advice for anyone with health concerns is to consult a health professional first.

Above 10 square feet in a building with 10 or more apartments, the owner must hire a New York State Department of Labor licensed mold assessor and a separate licensed remediator, since state law bars one worker from doing both. HPD wants those filings before it accepts a Class B or C correction there, so beyond a small patch mold remediation in NYC is licensed work.

The Leak Behind the Mold

Clean the mold without fixing the water and the mold most likely comes back, as the EPA puts it. New York's duty is flat rather than a matter of effort. Section 27-2017.1 says the owner shall keep the premises free from indoor allergen hazards and shall expeditiously remediate the condition and any underlying defect, which the code defines to include a water leak, water infiltration from plumbing or defective masonry pointing, and other moisture conditions. A landlord who says they tried has not met that standard while the mold is there and the leak is unfixed.

HPD's own report names these as significant contributors: poor roofing, failing pointing, indoor plumbing defects. Describe the water in your notice as much as the growth. A stain that spreads after rain, a ceiling patch under an upstairs bathroom, a cold wall that sweats in winter. The Health Department treats mold returning quickly after cleaning as a sign of an underlying problem such as a leak.

Checking the Building's Mold Record

HPD issued more than 47,000 mold violations in 2024, the figure it cited when launching a joint awareness campaign with the Health Department in May 2025, so the pattern at your own address is worth reading. You can look up any NYC address and see the HPD violations, complaints and legal actions attached to it, along with DOB records and rodent and bed bug reports, without an account. Repeat mold violations in different apartments point to a building-wide water problem. If you are still deciding whether to rent there, check the address against the rental due-diligence checklist before paying a deposit.

Frequently Asked Questions

Is black mold dangerous to breathe?

Mold exposure can cause or worsen asthma symptoms and allergies: congestion, a runny nose, coughing and trouble breathing in people sensitive to it. The CDC states that no test proves an association between Stachybotrys chartarum and particular symptoms. See a health care provider about symptoms you think are mold related.

Is black mold dangerous if you do not disturb it?

Leaving it alone does not make it safe and does not stop it spreading, because the moisture feeding it is still there. The CDC and the EPA treat every mold the same for removal. The risk in disturbing a patch is dust, which is why the city's work practices call for misting it first.

Do I need a mold test to prove it to my landlord?

No. The CDC does not recommend mold testing, and the EPA calls sampling unnecessary where growth is already visible, because no federal limit exists to compare a result against. HPD writes a violation on what an inspector can see and measure, so photographs and a 311 record beat a lab report.

Does mold on bathroom tile count as a violation?

Section 27-2017.3 excludes mold on tile or grout, so growth confined to shower tile and the grout lines falls outside the violation. Mold on the wall or ceiling above the tile, or around a leaking fixture, counts toward the square footage. A leak feeding tile growth is still an underlying defect.

Is it legal for a landlord to rent an apartment with mold in it?

Visible mold in a room of an apartment in a building with three or more apartments becomes a violation the moment an inspector records it, and the owner then has 90, 30 or 21 days to correct it. Before re-letting a vacant apartment the owner must remediate mold and certify that to the incoming tenant.

Does the mold law cover NYCHA apartments?

Section 27-2017.12 excludes NYCHA apartments from the indoor allergen hazard article, so the square-footage tiers and escalation rules do not apply to public housing. NYCHA residents report mold through NYCHA's own maintenance process rather than as an HPD violation. Health Department guidance on safe removal still applies.