A leaking cooling tower doesn’t always announce itself with a puddle on the mechanical room floor. Many leaks are subtle — a slow drip from a corroded basin, a hairline crack in a fill panel, or a valve that doesn’t seat properly. Left undetected, even a small leak can waste thousands of gallons per month and quietly inflate your water and sewer bills.
The Warning Signs
The most reliable indicator of a cooling tower leak is an unexplained increase in makeup water consumption. If your tower’s water usage jumps without a corresponding increase in heat load, building occupancy, or ambient temperature, something is wrong. A 10 to 15 percent increase in makeup water that can’t be explained by operational changes almost always points to a leak somewhere in the system.
Other warning signs include visible water staining on the tower basin, around pipe connections, or on the mechanical room floor below the tower. Corrosion streaks running down the exterior of the tower shell are another telltale sign — water is escaping through a crack or joint and leaving mineral deposits behind as it evaporates on the outside surface.
The U.S. Department of Energy’s cooling tower management guidelines recommend regular visual inspections specifically because small leaks can persist for months before they’re noticed through billing alone.
Common Leak Locations
Cooling tower leaks tend to occur in predictable places. The basin is the most common culprit — years of water exposure, chemical treatment, and thermal cycling take a toll on basin seals and coatings. Overflow pipes that are set too low or have failed float valves can discharge treated water directly to the drain without anyone realizing it. Pipe connections, especially at the makeup water line and blowdown line, develop leaks at joints and valves over time.
Distribution nozzles and spray headers can crack or become misaligned, sending water outside the fill media and down the exterior of the tower. And don’t overlook the blowdown valve itself — a blowdown valve that’s stuck partially open will continuously discharge water to the sewer, which shows up as excess water consumption but not as a visible leak.
How Submetering Catches Leaks Early
The fastest way to detect a cooling tower leak is with a dedicated submeter on the makeup water line. When you’re monitoring makeup water flow in real time, a leak shows up immediately as an unexplained deviation from baseline consumption. Without a submeter, you might not notice the problem until your next quarterly utility bill review — by which time you’ve already wasted tens of thousands of gallons.
Real-time monitoring takes this a step further. A continuous water monitoring system can alert you within hours when consumption patterns shift. If your tower normally uses 80,000 gallons per month and suddenly starts pulling 95,000 gallons with no change in building load, you get an alert — not a surprise bill three months later.
According to the EPA’s WaterSense program for commercial buildings, fixing leaks in cooling systems is one of the highest-impact water conservation measures available, often reducing total building water consumption by 5 to 15 percent.
What a Leak Costs You
The cost of a cooling tower leak goes beyond the wasted water. Every gallon that leaks out must be replaced with treated makeup water, which means higher chemical treatment costs. And because most utilities charge sewer based on total water consumption, you’re also paying sewer charges on every leaked gallon — water that went straight to the ground or down a drain rather than through your building’s sewer system. A leak of just 5 gallons per minute — which looks like barely more than a fast drip — adds up to over 200,000 gallons per month. At combined water and sewer rates of $15 per thousand gallons, that’s $3,000 per month in unnecessary charges.
Ready to Find Out What You Could Save?
RPM Water Equity Solutions helps commercial facilities recover money lost to sewer billing assumptions. If your building has cooling towers, you may be paying sewer charges on water that never reaches the sewer system.
Request your free assessment today and find out how much you could recover.
Find It Before It Finds Your Budget
Cooling tower leaks are common, progressive, and expensive — but they’re also detectable and fixable. Regular visual inspections, dedicated submetering, and real-time monitoring are your three lines of defense. If you haven’t checked your tower’s water consumption against its expected baseline recently, now is the time. The leak you catch today could be saving you thousands by next month.
