Outdoor power washing can negatively impact water quality if not done correctly. In addition, State and Federal laws dictate the use and disposal of certain cleaning chemicals. Failure to do so can lead to significant fines for both the University and contractors. The following guidelines clarify the correct way to power wash outdoor surfaces.

Type of Surface Cleaning Method Proper Disposal of Wastewater
Sidewalks, Plazas Without Soap: Dry cleanup first (broom), then wash. Screen wash water, if needed, to catch debris, then discharge water to landscaping, gutter, street or storm drain.
With Soap: Dry cleanup first (broom), then block storm drains and contain runoff. Collect water, screen water to remove solids, and pump wastewater to the sanitary sewer. Make sure pH is between 6 and 10 before disposing of the water into the sanitary sewer. (Contact EHS if you need help verifying the pH.)
Parking lots, Driveways, Restaurant/Food Handling Areas, Dumpster Areas, Loading Docks, Grease Storage With or Without Soap: Clean up any oil, grease, or dumpster discharge using absorbents. Sweep and bag absorbents for disposal. Block storm drains and contain runoff. Collect water, screen water to remove solids, make sure pH is between 6 and 10, and pump wastewater to sanitary sewer.

Contact EHS for assistance with alternative disposal options if there is a high concentration of petroleum products.

Unpainted Building Surfaces, Exterior Brick and Masonry Walls, Wood Decks, etc. Without Soap: Screen runoff for solids. Discharge water to landscaping, gutter, street, or storm drain.
With Soap: Block storm drains and contain runoff. Collect water, screen to remove solids, make sure pH is between 6 and 10, and pump wastewater to sanitary sewer.
Painted surfaces without loose paint (call EHS for assistance to determine paint’s lead content). Without Soap: Use high-pressure water, no soap. Lead-free paint: Screen wash water, if needed, to catch debris, then discharge water to landscaping, gutter, street or storm drain.

Paint contains lead: Collect water, screen to remove lead and solids, make sure pH is between 6 and 10, and pump to sanitary sewer.

Painted surfaces being cleaned to remove paint or graffiti (call EHS for assistance to determine paint’s lead content). With or Without Soap: Block the storm drain and contain runoff. Collect water, screen to remove solids, make sure pH is between 6 and 10, and pump to sanitary sewer.

Please note that biodegradable soap is subject to the same disposal procedures as any other soap.

Contact EHS at 919-962-5507 if you have questions or need assistance setting up a power washing operation on campus. More details on how to collect and dispose of washwater.