Exterior Cleaning and Power Washing
Before cleaning outdoors, OSEH Environmental and Hazardous Materials Management should be consulted (6-1920) for the proper procedures to follow. Be aware of the impacts that any dislodged pollutants or cleaning products might have on groundwater and surface waters. Avoid using acids and other toxic cleaners, and whenever possible, use plain water. If this is not possible, use a less toxic cleaner.

Washing with water
If only water is being used to clean a non-polluted surface, all storm drains must be blocked, or filter fabric or silt sacks must be installed to filter solids from runoff. The fabric or sack must be emptied of collected sediment as needed. It is important to limit sediment from entering catch basins because it can clog lines and lead to localized flooding and high maintenance costs. When work is complete, sediment and other solids that remain on the ground should be cleaned up immediately before they are washed into the storm system.

Washing with water and detergents or chemical applications
Before any cleaning with detergents or chemicals begin, test-wash with water only to determine if water is sufficient or if a cleaning additive is required. All chemical cleaning applications must be reviewed and authorized by OSEH for proper waste disposal requirements. The Michigan Department of Environmental Quality Waste Management Guidance for Mobile Power Washing outlines four potential disposal options. If the wash water does not meet the criteria for these disposal options, then it must be collected and tested to determine if it is a liquid industrial waste or if it is considered a hazardous waste.

On campus there are two options that are recommended for managing wastes generated by outdoor washing/cleaning activities:

1. Collect all wash water into appropriate (chemical compatible) containers.
• Containers must be labeled, immediately after waste is added, with appropriate contact information and the contents of the container, including chemical constituents in the waste. Containers and labels may be acquired from OSEH at 3-4568.
• Sample and analyze the waste for constituents of concern and determine proper waste management and disposal. Contact OSEH at 6-1920 to provide sampling, analysis, and subsequent waste management options. Note: Analysis will need to be performed on a representative sample of the waste and may take up to 10 business days.
• All liquid industrial waste or hazardous waste must be disposed through an OSEH approved contractor. If the wash water meets the requirements for disposal to the sanitary sewer, OSEH will make the proper arrangements with the City of Ann Arbor WWTP.
• If the material is a liquid industrial waste or hazardous waste, all manifests must be reviewed and signed by an OSEH representative. Complete a draft manifest and fax it to OSEH at 3-1185. The manifest will be reviewed and any correction or additional information will be itemized and returned to you for completion of the final manifest. Once the manifest content is approved, contact OSEH to schedule an authorized staff member to sign the manifest during waste pickup.
2. Obtain approval from the Michigan Department of Environmental Quality (MDEQ) to discharge to the ground by “authorization by notification.” The authorization letter from MDEQ is good for 5 years. For the MDEQ application, rules, and technical guidance visit the MDEQ Groundwater Discharge web page. The approval has been obtained for UM employees working on campus. Contact OSEH to review the environmental requirements for your specific operation. Contractors must obtain approval as a mobile power washer which covers exterior cleaning activities throughout the State of Michigan. Please note that this approval applies only to discharge to the ground. Under this approval, discharge to the sanitary sewer or storm water drainage system is prohibited.

Contact OSEH at 6-1920 for assistance or additional information on these requirements.

Other Cleaning Alternatives
Instead of washing with water and chemical applications, determine what alternative dry methods are available. Use absorbents such as sawdust or vermiculite, brooms or wire brushed to clean pavement, building and equipment as much as possible. Mechanically remove and collect loose debris before applying water.