Hard water contains high concentrations of calcium, magnesium, and other mineral salts that, when heated and evaporated, can form scale deposits on the surfaces of the water-cooled condenser's heat exchangers. Over time, this scale acts as an insulating barrier between the coolant water and the condenser's metal surfaces, which impairs the heat exchange efficiency. As the scale thickens, it requires more energy to achieve the same cooling effect, leading to reduced system efficiency, higher operational costs, and increased wear on the system. Scale buildup can also lead to reduced flow capacity within the condenser, resulting in higher pressures and temperatures. To combat these effects, many water-cooled condensers employ water softeners that remove calcium and magnesium ions, or use anti-scaling chemicals to inhibit the formation of scale.

Water quality with extreme pH levels (either too acidic or too alkaline) can lead to corrosion of metal components in the water cooled condenser. Low pH (acidic) water can cause oxidation of metal surfaces, leading to rust and weakening the structural integrity of the condenser, while high pH (alkaline) water can cause alkaline corrosion, which breaks down metal surfaces. The presence of chlorides, often found in seawater or industrial cooling water, can accelerate pitting corrosion, leading to localized damage. To prevent corrosion, the water should be treated to maintain an optimal pH range, typically between 7 and 8.5, which is ideal for preventing both acidic and alkaline corrosion. Corrosion inhibitors, such as phosphates, zinc compounds, or silicates, are commonly used in conjunction with regular water testing to ensure water quality is within tolerable limits.

Water sources that contain sediments, dirt, or other particulate matter can lead to clogging and blockages within the water-cooled condenser's piping and heat exchanger systems. These solid particles can obstruct the flow of water, reducing its capacity to carry heat away from the condenser. The reduced flow increases the pressure inside the condenser and diminishes its overall cooling efficiency. Over time, sediment accumulation can lead to abrasive wear on internal components, further increasing maintenance needs and the potential for failure. To mitigate these issues, filtration systems or strainers are typically installed at the water inlet points to catch large particles before they enter the condenser. These systems are designed to remove sand, silt, and other suspended solids that could damage the internal components or reduce performance.

Biofouling occurs when microorganisms, such as bacteria, algae, and fungi, accumulate on the condenser’s heat exchange surfaces. When left unchecked, these microorganisms can form a biofilm, which acts as an insulating layer that significantly impairs heat transfer. The biofilm also promotes corrosion and clogging, further decreasing the system's efficiency. Biofouling is more common in systems using surface water (rivers, lakes, or seawater) that have higher levels of organic material. Algae growth is particularly problematic because it can block water flow and lead to increased power consumption as the system compensates for reduced heat transfer efficiency. To combat biofouling, water treatment systems often include chemical biocides (such as chlorine, bromine, or copper-based compounds) that kill microorganisms before they can establish a biofilm. Ultraviolet (UV) light treatment is another environmentally friendly option for preventing microbial growth.