What is the best practice before cleaning sewers?

Notifying downstream treatment plants before cleaning sewers is essential for several reasons. When sewers are cleaned, it can lead to the release of sediments and debris that may impact the treatment facilities' operations. By informing the downstream treatment plants, they can prepare for potential fluctuations in inflow and adjust their processes accordingly. This communication helps ensure that the treatment plant is ready to handle any sudden changes in wastewater quality or quantity, preventing operational disruptions and environmental impacts.

The other options, while they may have their place in a comprehensive safety and operational protocol, do not address the specific logistical and communicational needs critical to maintaining system integrity during sewer cleaning procedures.