Pressure washing wastewater guide for Arizona
Wash water planning starts before equipment is unloaded: identify the contaminants, drainage route, receiving system, and site-specific requirements.
Field guidance by Steve Tersakian, General Manager · Reviewed September 20, 2026
Why wash water needs a site plan
Pressure washing can mobilize sediment, oil, grease, detergents, paint particles, and other material. A storm drain is not automatically an approved disposal route. The property, contractor, and any environmental contact should identify where water can travel and what controls are required before work begins.
Map drains and contamination first
Walk the service area and document drains, slopes, low points, landscaped areas, sanitary connections, fueling zones, grease areas, coatings, and sensitive equipment. The cleaning method, chemistry, containment, and recovery plan should match the actual contaminant and the receiving system.
Use controls that fit the scope
Possible controls include dry cleanup before washing, drain covers, berms, vacuum recovery, filtration, storage, approved sanitary disposal, or off-site disposal. The correct combination depends on the property, local utility direction, wastewater characteristics, and applicable permits or rules.
Keep the scope and records clear
Commercial proposals should state who supplies water, which drains or areas are protected, whether recovery is included, how collected water is handled, and what documentation is provided. Site-specific requirements should be confirmed with the responsible city, utility, or environmental authority rather than assumed.