What sizes of systems does the filter backwash recycle rule apply to?

The filter backwash recycle rule applies to all sizes of water treatment systems, making the answer correct. This regulation is designed to enhance water treatment efficiency and sustainability across various system scales. By requiring that any backwash water be properly recycled, the rule helps ensure that valuable treatment resources are not wasted, regardless of whether the system is small, medium, or large. This inclusive approach allows all systems to benefit from improved water quality management and operational efficiency, reinforcing the importance of recycling in water treatment processes. Thus, the unified application of this rule supports best practices across the industry, promoting responsible water usage and environmental stewardship.