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If you manage a New York City building with a cooling tower, it is easy to group every cooling tower requirement under the same law. However, Local Law 97 has nothing to do with Legionella testing schedules, cooling tower registration, or routine compliance paperwork.
Cooling tower registration, maintenance, inspection, and Legionella testing fall under separate legislation, including Local Law 77 and Local Law 159. Each law has its own requirements, deadlines, and reporting obligations.
Local Law 97 regulates a different part of building operation: greenhouse gas emissions.
This guide explains what Local Law 97 requires, how cooling tower performance can affect a building’s emissions profile, what compliance planning involves, and what can happen when a covered building exceeds its emissions limit.
Local Law 97: The Basics
Local Law 97 is the centerpiece of New York City’s 2019 Climate Mobilization Act. It applies to most buildings over 25,000 gross square feet, along with certain multi-building lots and condominium developments that exceed the applicable threshold collectively.
Rather than regulating one piece of equipment, LL97 sets an annual limit on the greenhouse gas emissions produced by a covered building. The allowable limit is based on factors such as building size and occupancy classification.
Local Law 97 covers:
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Annual building-wide greenhouse gas emissions limits
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Emissions intensity thresholds based on occupancy type
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Phased compliance periods, with current limits running from 2024 through 2029
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Stricter emissions caps beginning in 2030
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Additional reductions every five years through 2050
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Annual reporting and certification through the Department of Buildings’ BEAM portal
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Financial penalties for buildings that exceed their applicable emissions limit
Building owners should review the NYC Department of Buildings’ Local Law 97 page for current information on covered properties, exceptions, reporting procedures, and penalty calculations.
Local Law 97 does not regulate cooling towers directly. It is separate from the city laws governing cooling tower operation and Legionella control.
Local Law 77 of 2015 established New York City’s cooling tower registration, maintenance, inspection, and Legionella testing requirements. Building owners can review Cooling Tower Compliance requirements for additional information on these obligations.
Local Law 159 of 2025 later revised those requirements. Beginning May 8, 2026, Legionella culture sampling increased from once every 90 days to at least once every 31 days during operating months.
Neither Local Law 77 nor Local Law 159 is part of Local Law 97. The three laws may apply to the same building, but they should not be treated as one combined regulation.
Where Your Cooling Tower Fits Into the Emissions Picture
Local Law 97 does not identify cooling towers in the same way it addresses boilers or on-site fossil fuel combustion. However, the cooling tower remains part of the mechanical system that affects how much energy the building consumes.
A cooling tower removes heat from condenser water before that water returns to the chiller. When the tower cannot reject heat efficiently, the rest of the cooling plant may need to use more energy to maintain the required temperatures.
Chillers are particularly affected. Warmer condenser water or reduced heat rejection can increase the amount of electrical power needed to meet the same building cooling load.
The added demand appears in the building’s overall energy use. Depending on the property’s energy sources and mechanical configuration, it may also increase the greenhouse gas emissions calculated under Local Law 97.
The effect is different for every building. A cooling tower problem does not produce the same energy or emissions increase across all properties. The impact depends on factors such as:
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Chiller type and efficiency
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Cooling tower size and condition
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Building load
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Equipment operating schedules
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Condenser water temperatures
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Pumping strategy
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Variable-speed fan controls
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Tower and chiller staging
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Water-treatment practices
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Building automation settings
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The building’s overall energy mix
Several tower conditions can contribute to higher plant energy use:
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Reduced heat rejection can increase chiller energy demand
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Scale buildup can restrict heat transfer
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Poor water treatment can lead to fouling, corrosion, and reduced thermal performance
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Clogged nozzles can create uneven water distribution
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Damaged fill can reduce contact between air and water
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Restricted airflow can limit the tower’s ability to release heat
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Incorrect fan controls can waste electricity
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A tower that no longer matches the building’s load may operate inefficiently
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Deferred maintenance can allow small performance losses to build over time
An oversized or undersized tower can create operating problems, but equipment size alone does not establish the energy impact. Controls, variable-speed fans, pumping configuration, and the original system design all affect how the tower performs under changing loads.
Cooling tower work should not be assigned a standard emissions reduction figure. A cleaning, repair, control adjustment, or replacement may improve plant efficiency, but the effect on LL97 performance depends on the complete HVAC system.
The tower should be reviewed as one part of the building’s wider mechanical and energy profile.
Compliance Steps for Building Owners
Local Law 97 compliance begins with a clear picture of how the building uses energy and which systems create the largest emissions load.
A practical starting point includes:
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Reviewing the building’s energy benchmarking data
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Using Local Law 84 reporting as a baseline for annual energy consumption
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Comparing current performance with the applicable LL97 emissions limit
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Identifying which building systems consume the most energy
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Reviewing cooling plant performance, including chillers, pumps, controls, and cooling towers
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Evaluating repair, maintenance, and upgrade options across the full mechanical plant
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Recording completed improvements for annual LL97 reporting
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Coordinating documentation with the professionals responsible for the building’s emissions filing
Energy benchmarking can show whether electricity or fuel use is increasing, but annual totals do not always reveal the source of the change.
Cooling plant data can provide additional detail. Condenser water temperatures, chiller energy draw, tower fan speeds, equipment run times, and plant controls can help identify where energy is being lost.
A physical cooling tower inspection may also uncover problems that energy reports cannot show, including scale, fouled fill, blocked nozzles, damaged fan components, poor water distribution, or failing controls.
LL97 compliance is a building-wide responsibility. A cooling tower assessment may identify practical opportunities, but it is one part of a larger review rather than a stand-alone solution.
Penalties for Non-Compliance
Buildings that exceed their emissions limit face penalties of up to $268 per metric ton of CO2 over the applicable cap, assessed annually. Reporting is due each year through the DOB’s BEAM portal, and excess emissions can trigger an annual civil penalty of up to $268 per metric ton of CO2e above the building’s limit. Penalties may recur in later years if the building continues exceeding its annual limit.
Planning ahead of the 2030 threshold can be considerably less costly than addressing a noncompliant building after penalties begin accruing. Retrofits, controls upgrades, and system evaluations all take time to plan and execute.
How Cooling Tower Maintenance and Upgrades Support the Bigger Picture
Compared to a full mechanical plant overhaul, keeping your cooling tower well-maintained, or upgrading an aging one, is a comparatively low-disruption step to take while you’re evaluating your building’s broader LL97 strategy. It won’t guarantee compliance on its own, but a tower operating at its intended efficiency gives your chillers less work to do, which is a reasonable place to start before committing to larger capital projects.
Frequently Asked Questions
What buildings does Local Law 97 apply to?
Local Law 97 generally applies to buildings larger than 25,000 gross square feet. It also covers certain groups of buildings on the same tax lot and condominium developments that exceed 50,000 square feet collectively.
Is Local Law 97 the same as Local Law 77?
No. Local Law 97 regulates greenhouse gas emissions across the entire building. Local Law 77 established New York City’s cooling tower registration, maintenance, inspection, and Legionella testing requirements. The laws have separate purposes and compliance obligations.
Are cooling towers directly regulated under Local Law 97?
No. Local Law 97 does not set a separate emissions limit for cooling towers. However, cooling tower performance can affect the amount of electricity used by the chillers, pumps, fans, and controls serving the cooling plant.
What happens if a building doesn’t comply?
Buildings that exceed their emissions limit may face penalties of $268 per metric ton of carbon dioxide equivalent above the applicable cap. The calculation is completed annually, and separate penalties may apply for missing or inaccurate reports.
Next Steps
Local Law 97 regulates greenhouse gas emissions across the full building. It is not a cooling-tower-specific law, and no single piece of equipment determines whether a property meets its emissions cap.
Cooling tower performance is one factor in the building’s broader mechanical and energy profile. Reviewing tower condition, heat rejection efficiency, controls, and maintenance practices can help identify potential opportunities to improve cooling-plant performance as part of a broader LL97 strategy.
Building owners can learn more about cooling tower maintenance and how routine maintenance can support efficient system operation. For aging or inefficient equipment, cooling tower upgrades or replacement may also be worth evaluating as part of a broader mechanical plant strategy.
For more coverage on this topic, see related articles on our publishing site.
