How NYC Landlords Can Clear It Before It Gets Upgraded
An HPD mold violation starts a clock, and if you miss the deadline the violation gets more serious, not less. A Class A notice can become a Class B, and a Class B can become a Class C, with shorter deadlines and stricter paperwork at every step.
The timing makes it worse. Heating season is here. Windows stay shut, radiators run hot, and warm, humid indoor air meets cold exterior walls. Condensation forms in bathrooms, kitchens and closets, and mold follows. For many NYC landlords, the first sign of trouble is a tenant complaint to 311 and an HPD inspection.
This guide explains how HPD classifies mold, how violations escalate, when you are required to hire licensed professionals, and what it takes to clear a violation the first time.
How HPD Classifies Mold Violations
Under Local Law 55 of 2018, NYC’s Asthma-Free Housing Act, HPD sorts mold violations by how much visible mold the inspector finds. The class sets your correction deadline.
Class | Visible mold found | HPD rating | Time to correct |
A | Under 10 sq ft in a room of an apartment; under 30 sq ft on one level, or under 50 sq ft in a hallway or common area | Non-hazardous | 90 days |
B | 10 to 29 sq ft in a room; 30+ sq ft on one level, or 50+ sq ft in a hallway or common area | Hazardous | 30 days |
C | 30 sq ft or more in a room of an apartment | Immediately hazardous | 21 days |
Two things are worth noting. First, square footage is measured per room, so several small patches in one bathroom can add up to a Class B. Second, Local Law 55 also requires owners to inspect apartments for indoor allergen hazards, including mold, at least once a year and at turnover. Waiting for a complaint is not the plan the law expects.
The Upgrade Trap: How Mold Violations Escalate
Mold violations do not sit still. Local Law 55 directs HPD to upgrade them when owners fall behind:
- Class A becomes Class B automatically if the mold has not been corrected within the certification period and the condition still exists, or if the violation was falsely certified.
- Class B becomes Class C if it is not certified as corrected on time, HPD reinspects and still finds mold, or the violation was falsely certified.
When an upgrade happens, HPD closes the original violation and issues a new, more serious one. That resets you onto a shorter clock with stricter documentation requirements.
This is not a rare event. HPD’s reports to the City Council show thousands of mold violations issued as upgrades every year, more than 13,000 in one recent fiscal year. Each one represents an owner who thought the problem was handled, or hoped it would wait.
Why certifying early backfires. HPD attempts to reinspect Class B and Class C mold violations even after an owner certifies them as corrected. Wiping down visible mold or painting over a stain may pass a glance, but if the moisture source is still there, the mold returns. A false certification is itself grounds for an upgrade. The only safe certification is one backed by a real fix.
When You Need Licensed Mold Professionals
Who is allowed to do the work depends on the size of your building and the size of the mold problem.
Buildings with 10 or more apartments. Local Law 61 of 2018 requires two separate, independent New York State–licensed contractors whenever there is more than 10 square feet of mold:
- A licensed mold assessor, who inspects the conditions and writes the remediation plan.
- A licensed mold remediator, who carries out the work.
The two must be independent of each other. The same company cannot assess the job and then remediate it. This rule applies whether or not HPD has issued a violation. Local Law 61 also covers buildings on a zoning lot with 25,000 or more square feet of non-residential floor area.
The contractors must also file with the NYC Department of Environmental Protection, including a Mold Remediation Work Plan Notification, and give you copies of those filings.
Buildings with fewer than 10 apartments. You are not required to hire licensed contractors. Your own staff can do the work. But you must still follow the safe work practices in Local Law 55, which include:
- Fixing the underlying moisture or leak first
- Isolating the work area and sealing openings
- Removing or cleaning moldy materials with methods that limit dust and spores
- Cleaning the area with a HEPA vacuum and leaving it dust-free
Even in smaller buildings, using licensed professionals gives you documentation that the job was done right, which matters if HPD comes back.
Certifying the Correction: Get the Paperwork Right
Fixing the mold is half the job. The violation stays open until HPD accepts your certification, and incomplete paperwork is one of the most common reasons violations linger.
For Class B and Class C mold violations in buildings with 10 or more units, HPD requires you to submit, along with the Certification of Correction:
- ☐ A copy of the mold assessor’s license
- ☐ A copy of the mold remediator’s license (or remediation supervisor license)
- ☐ Copies of the contractors’ filings with the NYC Department of Environmental Protection
For Class A violations, or any violation in a building under 10 units, the Certification of Correction alone is generally enough when your own staff did the work. If you used licensed contractors, include copies of their licenses.
If you miss the certification window, HPD’s post-certification process may require an Affidavit of Compliance (form AF-7) with supporting attachments. Getting it right during the original window is far simpler.
At Key Construction, we hand over a complete documentation package at the end of every mold job, so certifying is a matter of filing, not chasing paperwork.
Fix the Cause, Not Just the Stain
Mold is a moisture problem. Remove the mold without removing the moisture and you will be back in front of HPD within months. The most common sources in NYC buildings:
- Plumbing leaks behind walls, under sinks, and around tubs and toilets
- Roof and facade leaks that soak top-floor ceilings and exterior walls
- Poor bathroom ventilation, such as missing, broken or undersized exhaust fans
- Condensation on cold surfaces like exterior walls, window frames and uninsulated pipes
- Failed caulk and grout that let shower water into the wall cavity
Winter is peak condensation season. Once the heat comes on, a few low-cost steps reduce the risk across your building:
- Test every bathroom and kitchen exhaust fan, and repair or replace weak ones.
- Re-caulk tubs, showers and window frames that show gaps or staining.
- Insulate cold-water pipes and check exterior walls for cold spots.
- Inspect top-floor apartments after the first heavy rain or snowmelt.
- Respond to tenant leak reports within days, not weeks.
When mold is caused by deeper building problems, like rotted subfloors, failed shower pans or water-damaged drywall, remediation should go hand in hand with repair. Our remodeling team can rebuild what needs to be replaced, so the area is restored, not just cleaned.
What to Do the Day a Mold Violation Arrives
- Read the notice closely. Note the violation class, the apartment and room, and the certification deadline. Count back from that date.
- Check your building’s unit count. Ten or more apartments, with mold over 10 square feet, means Local Law 61 applies and you need a licensed assessor and a separate licensed remediator.
- Find the moisture source. Get the leak, fan or condensation problem diagnosed before any remediation starts.
- Schedule the work early. Licensed contractors book up in winter. Give yourself room before a 21- or 30-day deadline.
- Coordinate access with the tenant. Give proper notice and document every access attempt in writing.
- Collect every document. Licenses, DEP filings and the assessor’s post-remediation report.
- Certify on time, and only when it’s truly fixed. Submit the Certification of Correction with all required attachments before the deadline.
Frequently Asked Questions
Can my super clean up the mold? In a building with fewer than 10 units, yes, as long as the Local Law 55 safe work practices are followed. In a building with 10 or more units, your staff can handle mold under 10 square feet. Anything larger requires licensed, independent assessment and remediation contractors.
Can one company do both the assessment and the remediation? No. For jobs covered by Local Law 61, the assessor and remediator must be independent of each other.
Will painting over the mold clear the violation? No. Painting over mold is not remediation. HPD may reinspect, and a falsely certified violation can be upgraded.
What if I miss the certification deadline? A Class A violation that is still present gets upgraded to Class B, and a Class B can be upgraded to Class C after reinspection. You will also face a more involved post-certification process.
Does mold affect anything besides violations? Yes. Open violations show up in HPD’s public records and can complicate refinancing, sales and tenant relations. Mold is also a recognized asthma trigger, which is why the city regulates it so closely.
Clear Your Mold Violation With Key Construction
A mold violation is easier to clear in week one than in week four, and far easier than after an upgrade. Key Construction helps NYC property owners find the moisture source, remediate mold safely, repair the damage, and assemble the documentation HPD expects.
Call 929-999-4206 or contact us online to schedule an assessment. Learn more about our mold remediation services, or read our related guides on mold remediation in NYC and Class C lead paint violations.
This article is for general information and is not legal advice. Requirements can change; always confirm details on your violation notice and with HPD.