Before you act on a number here: which utility, zone and programs reach a building depends on its address, not its ZIP code. Confirm it for yours.
Who this is for: a chief engineer or facilities director whose cooling tower is throwing alarms, failing a Legionella test, quoted for replacement, or proposed for removal, in New York City, elsewhere in New York State, or in New Jersey. The decision: repair it, replace it, or take it out, and what each option does to the building’s compliance load, water bill, and chiller. The rules differ by address; each section says which one it describes.
The tower is where three problems meet
A cooling tower carries three obligations that nothing else in the plant carries at once. It is the equipment the Legionella rules are written about. It is the largest water consumer in most buildings that have one. And it sets the condenser-water temperature that decides how hard the chiller works. A tower decision made on any one of those alone usually gets the other two wrong: a replacement in kind that keeps a water bill nobody has measured, or a removal that trades a compliance burden for a chiller that runs hotter every summer afternoon. The evidence for the decision exists in the building already. The job is to pull it together before the quote is signed.
What the tower is doing for the chiller
A tower rejects heat by evaporating a fraction of the water it circulates. The number that describes how well it is doing that is the approach: the leaving condenser-water temperature minus the wet-bulb temperature of the entering air. A common design point is 85°F condenser water at a 78°F wet bulb, a 7°F approach. Most water-cooled chillers are designed for entering condenser water at or below 85°F; above that, condensing pressure rises and the compressor draws more power for the same cooling. A fouled fill, a failed fan, or a scaled basin shows up first as a widening approach, then as chiller kW, then as complaints. That is why the first question in a tower review is not “what does a new one cost” but “what approach is this one holding, and what is the chiller paying for it.” Replacing the tower with air-cooled equipment removes the tower’s obligations and its water use, and also removes the low condensing temperatures a wet tower makes possible. Whether that trade pays depends on the building’s load profile, and it has to be worked out, not assumed.
The water the tower uses, and what it costs
Makeup water equals evaporation plus blowdown plus drift. Evaporation does the cooling and cannot be reduced without reducing the load; blowdown is the water sent to drain to keep dissolved solids in range, and it is the part a treatment program controls through cycles of concentration. A 1,000-ton tower run at two cycles of concentration evaporates on the order of 25,000 gallons a day in season and sends a similar amount to drain; a 500-ton tower is in the range of five to six million gallons a year, a 160-ton tower one and a half to two million. In New York City, where water and sewer are billed together at $13.86 per hundred cubic feet from July 1, 2026 (the FY2027 Water Board rate), that volume is a line item worth reading off the meter rather than estimating. The same gallons cost less in most New Jersey systems, but the arithmetic is the same.
One water rule is specific to the City and matters to anyone considering a tower’s removal: the New York City Plumbing Code (§428.1.1) does not allow potable water to be used for once-through cooling. A system installed before 2011 may be grandfathered, but a replacement must use the same amount of water or less, so a single-pass system can never be replaced in kind. The alternatives are air-cooled equipment or a recirculating system, which is to say a tower.
New York City: the rulebook as of May 2026
This section applies inside the five boroughs. Towers here are registered with both the City and the State, and the stricter requirement governs.
Local Law 159 of 2025 took effect May 7, 2026, and the Health Department’s conforming amendments to its cooling-tower rules (24 RCNY Chapter 8) took effect the next day, May 8. Together they changed the operating routine for roughly 4,000 buildings with registered towers. Three cadences now run at once, and they are not the same thing:
- Legionella culture testing at least every 31 days while the tower is operating, by a laboratory accredited under the State’s Environmental Laboratory Approval Program, with a signed chain of custody and the lab’s ELAP number on the report. The previous interval was 90 days.
- Routine monitoring documented at least weekly while the tower is in use.
- A compliance inspection documented at least every 90 days while the tower is in use.
The amended rules also require the Maintenance Program and Plan to be certified annually by a qualified person and to include a valve schedule and provisions for low-flow and no-flow conditions; a startup sample within 3 to 14 days of starting the tower and a sample 3 to 31 days after any hyperhalogenation; electronic notice to the Health Department within five days of every shutdown and startup, plus reporting of the operating period; commissioning and start-up fill from the municipal supply unless a nonpotable plan has been approved; and records kept for at least three years and produced on request, with electronic records shown on a device the owner supplies at inspection. The duties that predate 2026 still apply: cleaning and disinfection within 48 hours at 10,000 CFU/mL or above, a report within 24 hours at 1,000 CFU/mL or above, test dates reported within five days, and the annual certification by November 1.
Penalties come from two places, and vendor summaries routinely conflate them. The statute (Administrative Code §17-194.1) caps civil penalties at $2,000 for a first violation and $5,000 for a second or later one; $10,000 applies only to a violation involving or resulting in death or serious injury. Violating an abatement order is a misdemeanor punishable by up to $25,000 and a year. Separately, the Health Department’s own schedule (24 RCNY §8-09, as amended) sets first-offence amounts of $2,000 for operating without a maintenance program and plan, for failing to produce the annual certification, for Legionella sampling or reporting failures, and for failing to take required corrective action; $1,000 for most recordkeeping, monitoring, and water-treatment violations; and $500 for late shutdown, startup, or test-date reports. Each doubles on repeat. Summonses are heard at OATH. “$10,000 per testing violation” and “$25,000 for failing to disinfect,” both of which circulate in sales material, are not what the rules say.
New York State outside the City: the older cadence still applies
This section applies to Westchester, Long Island, and upstate.
The State Sanitary Code (10 NYCRR Subpart 4-1, in force since 2016) covers any cooling tower, evaporative condenser, or fluid cooler with no size threshold. It requires registration with the State before operation and on any change of ownership, an ASHRAE 188-based plan, Legionella culture sampling at most every 90 days, bacteriological sampling at most every 30 days, inspection at most every 90 days, notice to the local health department within 24 hours at 1,000 CFU/mL or above, annual certification by November 1, and records for at least three years. The certifier may be a New York professional engineer, a certified industrial hygienist, a certified water technologist, an environmental consultant, or a water-treatment professional with ASHRAE 188 training. The State sets no dollar penalty of its own; the rule refers to “all civil and criminal penalties as provided for by law,” with each day a separate violation. The 2026 tightening was the City’s; as of October 27, 2026, Subpart 4-1 has not been amended, and a State bill that would add biannual certification (S8472) has not been enacted.
New Jersey: no tower rule, but a water management deadline in December
This section applies to New Jersey.
New Jersey has no cooling-tower registry, no mandated testing cadence, and no state Legionella rule aimed at towers specifically. What it has is P.L. 2024, c.66, which requires a written water management program following ASHRAE 188 for hospitals, nursing homes and similar care facilities, correctional facilities with central hot water, residential buildings of six or more floors with a central water heater, and any building with an open- or closed-circuit cooling tower or evaporative condenser serving HVAC or refrigeration, among other listed aerosolizing devices. The program covers the listed device, not the whole building, unless the law says otherwise. The deadline to have the program developed was September 12, 2026; the deadline to have it implemented, with a public notice posted, is December 12, 2026. Both are set by the statute itself and do not depend on agency rules.
Three things the law does not do: it names no credential for whoever writes the program, it funds nothing, and it creates no registry. Legionella sampling is mandatory only for hospitals, care facilities, and buildings associated with an outbreak; for a commercial building with a tower, sampling is “may,” and the program decides. Records must be kept five years and be available to the Department of Health on request. Penalties run up to $2,000 for a first violation, $5,000 after, and $10,000 where a violation causes serious injury or death. The Department of Health has posted a program template and a letter to tower operators recommending Legionella testing at least every three months, but the rules the law called for from the Departments of Health and Environmental Protection have not been proposed as of October 27, 2026; when they are, they may add a cadence, a registry, or a credential (see New Jersey water management programs). Until then the statute is the whole of the obligation.
What each option does to the obligations
| Option | New York City | New York State outside the City | New Jersey |
|---|---|---|---|
| Keep and repair | All Chapter 8 duties continue: 31-day cultures, weekly monitoring, 90-day inspections, annual certification, five-day reports. A repair that takes the tower out of service is a shutdown and a startup, each reported within five days, with a startup sample due within 14 days. | Subpart 4-1 continues: 90-day cultures, 30-day bacteriological samples, 90-day inspections, certification by November 1. | The c.66 program must cover the tower and be implemented by December 12, 2026. |
| Replace in kind | The new tower is registered, commissioned with municipal fill water, and sampled within 3 to 14 days of startup; the Maintenance Program and Plan is rewritten for the new equipment and certified. The compliance load does not change. | Registration is updated; the plan is rewritten; the cadence is unchanged. | The program is updated for the new device. No registration exists to update. |
| Remove (air-cooled replacement) | The tower’s Chapter 8 obligations end with its deregistration; the Plumbing Code still bars once-through cooling, so the replacement is air-cooled or another recirculating system. Whether the building’s other duties change depends on what else it has. | The tower’s Subpart 4-1 obligations end with deregistration. | If the tower was the building’s only listed device, the c.66 program no longer has a device to cover. If the building also has a spa, fountain, humidifier, or central hot-water system of a covered type, the program continues for those. |
The right column is the one to read carefully. “Remove the tower and the compliance problem disappears” is true only when the tower was the only covered device, and it says nothing about what the chiller does without 85°F condenser water. The removal case has to be made on water, energy, and compliance together.
What a tower decision review produces
The review starts from records the building already keeps or can meter: the approach the tower is holding against design, chiller kW against condenser-water temperature across a season of trend data, makeup and blowdown volumes from the meter rather than the treatment contract, cycles of concentration, the Legionella and inspection record for the last three years, and the compliance posture at the building’s address under the rules above. It produces a dated comparison of repair, replace, and remove with the water cost, the chiller energy cost, and the compliance obligations shown for each, and it names the facts that still need a test or a meter rather than estimating them. It is an engineering assessment, not a water-treatment contract and not a legal opinion; where the State certification or the City’s annual plan certification requires a qualified person, the review says what that person will need.
Sources and dates
- NYC Administrative Code §17-194.1; Local Law 159 of 2025 (effective May 7, 2026); 24 RCNY Chapter 8 as amended, Notice of Adoption (hearing March 16, 2026), in force May 8, 2026; NYC DOHMH press release, May 8, 2026 (≈4,000 registered buildings). The §8-09 amounts are read from the Notice of Adoption and corroborated by a June 2026 legal summary; verify against the current rule text before quoting a specific figure.
- NYC Plumbing Code §428.1.1; 15 RCNY §20-06. NYC Water Board rate adoption, June 10, 2026 (6.0% increase effective July 1, 2026); the per-hundred-cubic-feet figure is derived from the prior year’s combined rate and should be read as approximate.
- 10 NYCRR Part 4, Subpart 4-1 (effective July 6, 2016); NYS S8472 (pending).
- P.L. 2024, c.66 (N.J.S.A. 58:12A-12.10 et seq.; 26:1A-139 et seq.), §6; OLS fiscal estimate for S2188.
- Tower and chiller figures are standard design practice (approach, 85°F entering condenser water) and order-of-magnitude water balances; the building’s own meters supersede them.
- Last reviewed October 27, 2026. The New Jersey section changes on December 12, 2026 and whenever DOH or DEP rules appear; the New York State section changes if Subpart 4-1 is amended.