CWEA Maintenance Technologist Practice Test 2025 – Complete Exam Prep

Backwashing in filtration systems is primarily conducted to remove trapped particulates and restore the efficiency of the filter. Over time, filters accumulate various contaminants and dirt from the water being treated. This accumulation can lead to a decrease in flow rate and a decline in the filter's performance. By reversing the flow of water through the filter during backwashing, these trapped particles are dislodged and flushed out, allowing the filter to function effectively again.

This process is essential in maintaining the optimal operation of filtration systems, ensuring that they continue to provide clean and safe water. The other options do not accurately represent the key function of backwashing: cleaning water before treatment typically happens in pre-treatment phases; adding chemicals to the filter is not part of backwashing, and reducing water flow is actually a result of filtration buildup, which backwashing seeks to counteract.