Water Operator Class 3 Practice Test 2025 – Your Complete Guide to Mastering Certification Success!

During backwashing, filter beds should ideally expand by around 50%. This expansion is crucial because it ensures that trapped particles are dislodged effectively, allowing for proper cleaning of the filter media. The process involves reversing the flow of water through the filter, which creates turbulence and allows for the separation of accumulated solids from the media.

An expansion of approximately 50% promotes adequate movement of the filter media, which enhances the removal of debris and particulates that have built up during normal filtration operations. This degree of expansion helps maintain the effectiveness of the filter and prolongs its life by preventing excessive clogging that can diminish filtration performance.

While smaller percentages would allow some level of cleaning, they would not provide the thorough backwash necessary to properly restore the filter to optimal operating conditions.