Reading Time | 10 Minutes
Your cooling tower is working hardest right now — peak load, high ambient temperatures, maximum evaporation. The mechanical side of the system gets most of the attention in summer, but the cooling tower water chemistry protecting it is quietly running into trouble, often before any alarm goes off.
Here’s what’s actually happening.
Cooling towers reject heat through evaporation. In peak summer conditions, that evaporation rate climbs significantly, which means dissolved solids concentrate in the basin water faster than at any other time of year.
Conductivity — a measure of total dissolved solids (TDS) in the water — is the primary indicator of concentration levels. As evaporation accelerates, conductivity rises. If blowdown (the controlled discharge of concentrated basin water, replaced with fresh makeup) isn’t adjusted to compensate, the system runs at higher cycles of concentration than it was designed for.
Higher cycles push scale-forming ions — calcium, magnesium, silica — above their solubility limit. At that point, they start depositing on heat transfer surfaces. Your inhibitor package was formulated for a specific cycle range. Run consistently above it, and the chemistry protecting your system isn’t doing the job you’re paying for.
Conductivity in a cooling tower is a measurement of how many dissolved minerals and salts are present in the recirculating water, expressed in microsiemens per centimeter (μS/cm). Rising conductivity signals that evaporation is concentrating dissolved solids faster than blowdown is removing them — the core chemical warning sign of summer heat stress on a cooling tower.
| Parameter | Target Range | What Deviation Means |
|---|---|---|
| pH | 7.5–9.0 | Corrosion risk below range, scale risk above range |
| Conductivity / Cycles of Concentration | Per program target | Indicates how concentrated the water has become |
| Inhibitor Residuals | Per program spec | Below target = unprotected metal surfaces |
| Oxidizing Biocide | 0.2–0.5 ppm free chlorine | Below range = microbial growth risk |
| Legionella | Not detected | Immediate action required |
Summer moves faster than a quarterly schedule. A quick conversation with our team can tell you whether your chemistry has already drifted out of spec.
Talk to Our Water Treatment Team →Corrosion and scale inhibitors are dosed in proportion to makeup water volume. When evaporative loss spikes in summer, that relationship changes. If dosing rates aren’t recalculated to account for increased evaporation, inhibitor residuals fall below effective range — even though the program looks the same on paper.
An under-inhibited system can develop corrosion and scale at the same time. Both problems reduce heat transfer efficiency, shorten equipment life, and create fouling that costs significantly more to remediate than to prevent.
Most cooling tower water treatment programs are reviewed on a quarterly schedule. In summer, conditions can move outside of spec in a matter of weeks. A quarterly review cadence doesn’t match the pace at which peak-season chemistry drifts.
Warm water accelerates microbial growth, including Legionella, while simultaneously reducing the effective contact time of some oxidizing biocides. A biocide dose that held microbial counts in check in April may not be doing the same job in July.
This is why summer requires active monitoring — not a program set in spring and left to run on its own schedule.
In peak season, a program that looked fine in April can be under-protecting your system by July. We can help you confirm where you actually stand.
Get Your Cooling Tower Reviewed →Heat transfer efficiency drops gradually. Deposits build on condenser tubes. Inhibitor residuals come back low on a monthly test, but weeks have passed since anything was adjusted. By the time the problem is visible operationally, the remediation cost is significantly higher than early intervention would have been.
What we typically find when we walk a system that hasn’t been reviewed since spring is that conductivity has been running high for weeks — and nobody caught it, because blowdown was on a fixed timer, not tied to actual water quality.
Digital remote monitoring changes this: real-time conductivity data linked to automatic blowdown control means the system responds to actual evaporation conditions, not a seasonal schedule that no longer fits.
If your cooling tower hasn’t been reviewed since the weather changed, work through these five checks:
If your cooling tower services haven’t been reviewed since peak season started, now is the right time.
We'll walk your system, verify your conductivity, inhibitor, and biocide program against summer conditions, and give you a plain-English report on what to fix. No obligation.
Start a Conversation →ChemREADY offers a free on-site water analysis — we’ll walk your system, test your water, and give you a plain-English report on your conductivity, inhibitor, and biocide program. No obligation.
Schedule Your Free On-Site Analysis →Or call us: 800-229-6801
Real-time conductivity linked to automatic blowdown keeps the system responding to actual conditions. See how digital remote monitoring works →
A managed program adjusts to peak-season conditions instead of a fixed calendar. See how ChemREADY manages cooling tower water treatment →
We also handle water safety and Legionella, wastewater, and dewatering. Tell us what you run and we’ll point you to the right team →
