Mold shows up in your apartment and the first question is always the same: who has to deal with it? In NYC, the answer depends on what caused the mold and who controls that cause. 

Here is how responsibility breaks down under New York law.

The Short Answer

In most cases, the landlord is responsible. New York’s warranty of habitability requires landlords to keep rental units safe, sanitary, and livable. If mold grows because of a building issue like a plumbing leak, roof damage, or poor ventilation, that falls on the landlord to fix.

When the Tenant Shares Responsibility

Tenants are expected to keep their apartment reasonably clean and report problems promptly. If mold grows because you never run the exhaust fan, block ventilation, dry clothes indoors regularly, or fail to report a leak for weeks, the landlord may argue that you contributed to the problem.

When Both Are at Fault

Sometimes responsibility is shared. A pipe leaks inside the wall (landlord’s problem), but the tenant does not report it for two months. In that case, both parties played a role. The landlord should have maintained the plumbing, and the tenant should have reported the signs of mold sooner.

What NYC Law Says About Mold Responsibility

New York City has some of the strongest mold regulations in the country. Multiple laws work together to define who is responsible and what they have to do.

Warranty of Habitability

Every residential lease in New York includes this protection, and no lease clause can waive it. Landlords must keep the apartment free from conditions that are dangerous or harmful to health. Mold that affects health or safety violates this warranty.

NYC Local Law 55

This law applies to buildings with three or more apartments. It requires landlords to inspect units annually for mold and pest hazards, respond promptly to tenant complaints, follow safe remediation practices, and provide tenants with the NYC Department of Health’s Local Law 55 Fact Sheet.

NYS Mold Law (Article 32)

Under this state law, all mold assessment and remediation work must be done by NYS Department of Labor licensed professionals. The same entity cannot perform both assessment and remediation on the same project to prevent conflicts of interest.

Landlord Responsibilities in Detail

If you are a landlord or property manager in NYC, these are your legal obligations when it comes to mold.

Fix the Source

Mold is always a moisture problem. Your job is not just to clean the visible mold but to identify and repair the underlying cause, whether that is a leaking pipe, a failing roof, poor drainage, or inadequate ventilation.

Hire Licensed Professionals

For mold covering more than 10 square feet in buildings with 10 or more units, you are required to hire NYS-licensed mold assessors and remediators. A licensed assessor must prepare a written remediation plan before any work begins.

Act Within HPD Timeframes

If HPD inspects and issues a mold violation, you have a limited window to fix it:

• Class A: Mold under 10 sq ft. 90 days to correct.
• Class B: Mold between 10 and 30 sq ft. 30 days to correct.
• Class C: Mold over 30 sq ft. 24 hours to correct.

Missing these deadlines can result in fines, legal action, and tenant rent reductions.

Disclose Mold History

Before signing a lease, landlords must inform tenants about previous water leaks or mold issues and any remediation work that was done. Hiding known mold problems can lead to claims of fraud or misrepresentation.

Tenant Responsibilities

Tenants are not off the hook entirely. You have a role in preventing mold and reporting it quickly.

Report Problems Immediately

The moment you spot a leak, water stain, or signs of hidden mold, notify your landlord in writing. Email is best because it creates a dated record. Include where the mold is, when you noticed it, and any health symptoms.

Maintain Basic Upkeep

You are expected to keep moisture-prone areas like the bathroom and kitchen reasonably clean. Run exhaust fans during and after showers, wipe up standing water, and avoid creating excessive humidity indoors.

Handle Minor Surface Mold

Small amounts of mildew on tile or grout fall under normal household cleaning. If it is surface-level, covers a small area, and wipes away without returning, that is generally the tenant’s responsibility.

Do Not Attempt Large-Scale Removal

If mold covers a large area, keeps returning, or is accompanied by a strong musty odor, do not try to clean it yourself. Scrubbing without proper containment spreads spores through the apartment and can make the problem significantly worse.

What to Do If Your Landlord Ignores the Mold

This happens more often than it should in NYC. If your landlord does not respond after you report mold, you still have options.

Follow Up in Writing

Send a second written notice referencing your original message. Restate the issue and include any new symptoms or worsening conditions. Keep copies of everything.

Call 311

For private housing tenants, calling 311 triggers an HPD inspection. An inspector will visit your apartment, assess the mold, and issue violations against the landlord if warranted. This creates an official record that strengthens your position.

Request a Professional Inspection

If your landlord disputes the severity of the mold, a professional mold inspection provides independent, lab-verified documentation of the problem. This report carries weight in landlord-tenant disputes, HP Actions, and rent reduction proceedings.

Know Your Legal Options

If the landlord still does not act, NYC tenants can pursue several remedies:

• Rent reduction through DHCR for rent-stabilized tenants
• HP Action in Housing Court to compel repairs
• Withholding rent (proceed carefully and consult a housing attorney first)
• Lease termination if the apartment is rendered uninhabitable

Note: This is general information, not legal advice. Consult a housing attorney for guidance specific to your situation.

Common Scenarios and Who Is Responsible

Mold Under the Kitchen Sink From a Leaking Pipe

Landlord. Plumbing maintenance is the landlord’s responsibility. If a supply line or drain connection leaks and causes mold under the sink, the landlord must fix the leak and address the mold.

Mold on Bathroom Ceiling From Poor Ventilation

Usually the landlord. If the building’s ventilation system is inadequate or the exhaust fan is broken, that is a building maintenance issue. If the tenant has a working fan but never uses it, responsibility may shift.

Mold on Walls After Upstairs Neighbor’s Leak

Landlord. Water intrusion from another unit is a building issue. The landlord is responsible for repairing the source and remediating mold in your unit, even if the leak originated in someone else’s apartment.

Mold in Closet on an Exterior Wall

Depends on the cause. If condensation from poor insulation is the issue, that is the landlord’s responsibility. If the tenant packed the closet so tightly that zero airflow reached the wall, they may share some responsibility.

Recurring Mold After Previous Remediation

Landlord. If mold keeps coming back, the underlying moisture source was not properly fixed. The landlord is responsible for addressing the root cause, not just treating the surface repeatedly.

How a Professional Inspection Helps

Whether you are a tenant trying to hold your landlord accountable or a landlord trying to understand the full scope of the problem, a professional mold inspection gives both parties clear, unbiased answers.

What You Get

A licensed mold assessor will identify all visible and hidden mold, pinpoint the moisture source causing the growth, collect air and surface samples for independent lab analysis, and deliver a detailed report that serves as documentation for HPD complaints, legal proceedings, and insurance claims.

Why Independence Matters

Under NYS law, the company that assesses the mold cannot be the same company that remediates it. This separation exists to protect consumers. When you hire an assessment-only firm like GAC Environmental, the findings carry no financial bias.

Not sure whether you need an inspection, testing, or both? Our guide on mold testing vs. mold inspection explains the difference.

Final Thoughts

In NYC, the landlord is responsible for mold in most situations. But tenants who report early, document everything, and understand their rights get results faster. If you are dealing with mold in your apartment, get a professional inspection and get the facts on your side.