This area of the facility is used to limit cross-contamination between the raw feedstock, compost in advanced stages of composting, and cured compost. With strict washdown protocols in place, machinery used in the composting site could also be safely used elsewhere on the farm. In any case, trucks, loaders, and trailers hauling bio-hazardous material from the production area of the farm should be cleaned before leaving the site.

The washdown space should be separately bunded to prevent the wash water reaching other areas of the compost site. On the other hand, wash water could potentially be used to irrigate feedstock in the mix preparation area (but not elsewhere). A high-pressure hose should be used to clean all equipment after use. The use of disinfectant should be minimised because it could affect microbial activity during composting.