NYC Local Law 97 Explained: The 2026 Guide for Building Owners

Local Law 97 (LL97) is the centerpiece of New York City’s Climate Mobilization Act, passed in 2019. It sets greenhouse-gas emissions limits on most large buildings in the city and charges a penalty for every metric ton of carbon a building emits above its limit. For owners and operators, it has turned building energy use from an operating-cost question into a direct compliance and financial-risk question.

What Local Law 97 actually does

LL97 assigns each covered building an annual emissions limit (often called a “cap”) based on its size and how it is used — office, multifamily residential, retail, hospital, and so on. Different occupancy types have different emissions-intensity limits, because a hospital legitimately uses more energy per square foot than a warehouse. The city converts a building’s reported energy use into metric tons of carbon dioxide equivalent (tCO2e) and compares that total to the building’s limit.

If a building emits more than its limit, the owner owes a penalty of $268 for every metric ton of CO2e over the cap, assessed for each year of noncompliance. Stay at or below the limit and there is no penalty.

Who is covered

LL97 generally applies to buildings over 25,000 gross square feet, as well as to two or more buildings on a single tax lot, and certain condominium arrangements, that together exceed the threshold. Some building types — for example certain rent-regulated housing and a handful of other categories — follow alternative or prescriptive compliance paths rather than the standard emissions-limit path. If you are unsure whether your property is covered, the safe assumption for anything over 25,000 sf is that it is, until you confirm otherwise.

The two compliance periods

LL97 tightens over time. The first compliance period runs from 2024 through 2029, and the second from 2030 through 2034, with stricter limits in the 2030–2034 period. A building that comfortably meets its 2024–2029 cap can still face penalties in 2030 once the limit drops — which is exactly why owners who are compliant today still need a plan for the next deadline.

How you report

Covered buildings file an annual emissions report, due May 1 of the following calendar year, prepared and certified by a registered design professional. The first LL97 report — covering the 2024 calendar year — was due May 1, 2025. This sits alongside the separate LL84 benchmarking filing, which is the energy-use data foundation that LL97 builds on.

What building owners should do now

1. Confirm coverage and your cap. Know your gross square footage, occupancy classification, and the resulting emissions limit for both compliance periods.
2. Benchmark honestly. Your LL84 data feeds LL97, so accurate metering and reporting come first.
3. Estimate your exposure. Compare current emissions to your limit to see whether you face a penalty today and how much larger the gap becomes in 2030.
4. Build a retrofit and financing plan. Many owners pair efficiency work with C-PACE financing so capital cost is not the blocker.

For the mechanics of how the penalty is computed, see how LL97 fines are calculated. For the next cliff, read our 2030 deadline guide.