DEP CATS Triennial Registration 2026: Is Your Boiler Due This Cycle?

Somewhere in your building’s mechanical room, a boiler is quietly burning fuel and, whether you’ve thought about it or not, quietly building a paper trail with the city. That paper trail is called DEP CATS Triennial Registration, and it doesn’t renew itself. Remember, keeping up with the DEP CATS Triennial Registration is crucial for compliance.

If you’re a property owner or manager in New York City, you already juggle enough deadlines — DOB filings, Local Law 152 gas inspections, insurance renewals. Boiler registration is easy to forget precisely because it only comes around once every three years. And that’s exactly why it catches people off guard.

Understanding the DEP CATS Triennial Registration process can save you from unexpected penalties.

This guide walks through what DEP CATS Triennial Registration actually is, how to tell if your boiler is due this cycle, and what happens if you let it lapse.

What Is DEP CATS Triennial Registration?

CATS stands for the Clean Air Tracking System. It’s the NYC Department of Environmental Protection’s online portal for filing boiler registrations, renewals, work permits, and other air-permit paperwork. The official DEP page for the system explains that CATS handles new boiler registrations, renewals, amendments, work permits, and inspection requests in one place.

DEP CATS Triennial Registration is the process of registering — and then re-registering every three years — boilers that fall within a certain size range, so the city can track fuel type, emissions, and operational status.

To ensure compliance, it’s vital to stay updated about your DEP CATS Triennial Registration.

DEP CATS vs. DOB Boiler Inspection: what’s the difference?

This is where a lot of owners get tripped up, so it’s worth spelling out plainly:

• • DOB (Department of Buildings) cares about safety. It wants to know your boiler won’t leak, fail, or become a hazard. That’s handled through the annual boiler inspection report filed with DOB.
  • DEP (Department of Environmental Protection) cares about air quality. It wants to know what’s coming out of your chimney. That’s handled through DEP CATS, on a three-year cycle.

In summary, the DEP CATS Triennial Registration is essential for maintaining your boiler’s compliance and air quality standards.

Filing one doesn’t satisfy the other. A current DOB inspection does nothing to protect you from a DEP violation for an expired CATS registration, and vice versa. They’re separate agencies, separate systems, separate deadlines.

How the 3-Year Cycle Actually Works

Here’s the part that surprises a lot of owners: there’s no single citywide “boiler registration year.” Your renewal date is tied to your own equipment’s approval date, not a calendar cycle everyone shares.

A Boiler Registration I is issued for three years from its date of approval. A Boiler Registration II follows the same three-year logic, counted from the initial approval date. That means if you manage more than one property — or even multiple boilers in the same building — each one can have its own expiration date.

So the honest answer to “is my boiler due in 2026?” is: it depends entirely on when your specific boiler was last approved. You can’t assume everyone’s cycle lines up with the calendar year, and you shouldn’t assume your building is safe just because a neighboring property recently renewed.

How to Check If Your Boiler Is Due for Registration

The good news is that DEP makes this lookup public. Here’s the quickest way to check your status:

1. Go to the DEP CATS public search tool, accessible through the Clean Air Tracking System page on nyc.gov.
2. Search by address or Building Identification Number (BIN). You don’t need a login to look up a property’s air permit history.
3. Review the registration record for status, registration type, and expiration date.
4. Cross-check equipment. If your building has more than one boiler, confirm each unit’s record separately — registrations are tied to individual equipment, not just the address.
5. Note the expiration date and mark your calendar well before it, since renewal filings are meant to go in ahead of time, not after the fact.

If the record shows “expired” or you can’t find a registration at all for equipment that should be covered, that’s your signal to act — not wait for a notice in the mail.

BTU Thresholds: Which Category Applies to You

DEP sorts boilers by heat input, and the category determines which filing applies:

• Boiler Registration I: 350,000 BTU/hr up to (but less than) 2.8 million BTU/hr. Filed and renewed as a standard triennial registration.
• Boiler Registration II: 2.8 million BTU/hr up to 4.2 million BTU/hr. Also renewed every three years, but these units additionally require annual tune-ups and combustion tests on top of the triennial filing.
• 4.2 million BTU/hr and above: These don’t use the registration process at all. They require a DEP work permit and Certificate of Operation instead.

There’s also an aggregation rule worth knowing: if one owner has several smaller boilers in the same building and their combined heat input reaches 350,000 BTU/hr or more, DEP can treat them as subject to registration even though no single unit crosses the threshold on its own. Don’t assume a boiler is exempt just because it looks small.

What Happens If You Miss Your DEP CATS Deadline

An expired registration doesn’t sit quietly in the background. Once a record flips to “expired” in DEP’s public database, it’s visible — and it’s the kind of thing that draws attention during a violation sweep, a due-diligence check on a sale, or a routine city inspection.

The consequences typically escalate like this:

• DEP violation issued for the expired or missing registration.
• Referral to the NYC Office of Administrative Trials and Hearings (OATH) if the violation isn’t resolved, where an unanswered case can lead to hearings and mounting penalties.
• Downstream complications, including delays to building sales, refinancing, or a Certificate of Occupancy, since open environmental violations tend to surface during those processes.

It’s also worth repeating: this is a separate track from DOB non-filer penalties. Being current with DOB doesn’t stop a DEP clock from running, and paying a DOB fine has no bearing on an open CATS violation. If you want to prevent penalties before they start, our DEP CATS Boiler Registration service page walks through the filing process, and if you’re already facing an open violation, our boiler violation removal team can help you work through it.

Acting promptly on your DEP CATS Triennial Registration will help you avoid complications.

CATS Expired Boiler Registration — How to Fix It

An expired registration isn’t the end of the road — it’s a renewal that’s overdue, not a new application from scratch, in most cases. To reactivate:

1. Locate your existing Application ID or Installation ID in CATS.
2. Select the renewal request option tied to that record.
3. Confirm and update ownership, contact, and property details, since expired records often have stale information.
4. Complete the certification and submit, along with the applicable fee.
5. Save the automated confirmation email DEP sends after submission — that’s your proof of filing if questions come up later.

If the registration has been expired long enough to generate a violation, the renewal filing and the violation response may need to be handled together, which is where professional help tends to save the most time.

DEP CATS Registration Checklist for 2026

Your DEP CATS Triennial Registration checklist will guide you through the required steps.

A quick, scannable version to keep handy:

• Look up every boiler’s registration status by BIN or address in the CATS public search
• Confirm which category applies — Registration I, Registration II, or Work Permit — based on BTU/hr
• Note the exact expiration date for each unit (they may differ across a portfolio)
• Submit renewal filings ahead of the expiration date rather than waiting for a DEP reminder
• Keep Registration II tune-up and combustion test records current alongside the triennial filing
• Save all confirmation emails and filing IDs for your records
• If a registration has already lapsed, prioritize the renewal before it escalates to a violation

The Bottom Line

DEP CATS Triennial Registration is easy to overlook precisely because it’s a three-year clock, not an annual one. The safest move is to check your status now rather than wait for a notice that may never arrive. If you’d rather not comb through CATS record by record, OneViewNYC Inspections can check your building’s status, handle the filing, and clear any violations already on record — reach out and we’ll take it from there.

Don’t overlook the importance of your DEP CATS Triennial Registration; it ensures your compliance and safety.