Copper corrosion can sneak up on industrial facilities, often showing up as pinhole leaks, blue-green staining, or sudden heat-exchanger failures. While operators typically look for obvious culprits like low pH or oxidizing biocides, several less obvious causes quietly drive copper degradation in cooling water systems. Here are three overlooked contributors.
1. Ammonia Contamination
Ammonia—even in very low concentrations—can attack copper alloys through a mechanism known as stress corrosion cracking. Industrial sites located near fertilizer storage, wastewater processes, food production, or combustion sources often see trace ammonia drifting into the cooling tower atmosphere. Once absorbed into the cooling water, ammonia disrupts protective copper oxide films and accelerates corrosion. Routine ammonia testing is often skipped, so this issue remains hidden until damage is already done.
2. Improper Oxidant/ Biocide Balance
Chlorine, bromine, and chlorine dioxide are essential for controlling biological growth, but excessive dosing can damage copper metallurgy. Many facilities rely on ORP setpoints, which don’t always match real oxidant levels due to probe drift or changing water chemistry. The result? Intermittent overfeeds that strip passivation layers from copper tubes. Facilities should pair ORP control with periodic grab sampling to verify oxidant residuals.
3. Galvanic Pairing With Dissimilar Metals
Even when copper is sound and water chemistry appears balanced, unseen galvanic interactions can create rapid localized corrosion. This often happens when copper is paired with steel, aluminum, or titanium components—even if they are separated physically. Electrical bonding, grounding, stray currents, and mixed-metal heat exchangers can all create galvanic pathways. The fix may be as simple as isolation gaskets, dielectric unions, or grounding corrections.
How To Protect Against Copper Corrosion
Copper corrosion is rarely caused by a single factor. A good water treatment program should include routine ammonia testing, biocide verification, and audits for galvanic issues. Identifying these hidden drivers early can extend equipment life, stabilize heat-transfer efficiency, and reduce costly downtime.