Mobile Power Washing ... Keep It Clean!

Information presented in this publication is intended to provide a general understanding of the statutory and regulatory requirements governing mobile power washing. This information is not intended to replace, limit or expand upon the complete statutory and regulatory requirements found in the Illinois Environmental Protection Act and Title 35 of the Illinois Administrative Code of Regulations.

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What is mobile power washing?

Water Spray Mobile power washing uses a high-pressure water system to clean vehicles and equipment. Power washing can include the following:

  • Transportation-related washing of trucks, semitrailer interiors, lunch wagons, food carts, and other vehicles
  • Surface washing of sidewalks, building exteriors, and other outside areas and structures
  • Food service and retailer washing of alleys and dumpsters

Water, detergents, degreasers, and other products are used for mobile power washing. Although solvent degreasers can also be used, this fact sheet does not cover mobile power washing using solvents. For more information on mobile power washing with solvents, call the Illinois Environmental Protection Agency (EPA) at (217) 782-0610.

Why is mobile power wash discharge a concern?

Mobile power washing, including power washing using water only, creates wash water (wastewater). Washing vehicles and equipment outdoors or in areas where wastewater flows onto surfaces where it cannot soak in, such as in concrete areas, can cause the wastewater to flow into storm drains. Because some storm drain systems discharge untreated water directly to water bodies such as creeks, rivers, lakes, and wetlands, discharging power wash wastewater into this type of storm drain system is the same as discharging wastewater directly into a water body.

Wastewater can contain high concentrations of oil and grease, detergents that may contain phosphates and suspended solids. Detergents, even biodegradable detergents, can be poisonous to fish. Phosphates, an ingredient in some detergents, are plant nutrients that can cause the excessive growth of nuisance plants when the phosphates enter lakes and streams. Wastewater can also contain dirt and pollutants from vehicles and equipment washing. If washing buildings or other items that are painted with lead-based paint, contact the Illinois EPA Bureau of Land at (217) 524-3300 for proper lead paint chip disposal.

Power washing also removes debris that if discharged can clog storm sewer inlets and grates and reduce or even prevent storm water drainage to the sewer.

What should I do with my mobile power wash discharge?

Wastewater discharge The suggestions listed below for mobile power washing can reduce the amount of pollutants discharged to water bodies through storm sewers.

  • Use a portable containment system or storm sewer manhole insert to catch wastewater from vehicle washing. Both of these methods use submersible pumps that can pump the wastewater to a sanitary sewer or a holding tank to be hauled off site and properly disposed of.
  • Find out if area storm and sanitary sewers are combined or separate systems. Many storm and sanitary sewers in the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) are combined before their final discharge point; therefore, most waste water is treated before it is discharged to water bodies. However, many newer areas and other cities have separate systems; therefore, wastewater discharged to storm sewers is discharged directly to water bodies without treatment to remove pollutants.
  • Prevent wastewater from discharging to storm sewers if storm and sanitary sewer systems are separate. Vehicles and equipment should be washed in grassy, vegetated, or gravel areas so that the waste-water can seep into the ground. Do not wash equipment or vehicles outdoors on saturated ground or on days when rain is probable. Items should not be washed over storm sewers, on paved areas, or any area that drains to a storm sewer. Seal storm drains so that wastewater cannot discharge to the drains.


Wastewater can be filtered before discharge to a sanitary sewer. Residue on the filter can be disposed of along with your general waste when completely dry. The MWRDGC requires that particles of 0.5 inch or more in any one dimension be filtered out of wastewater before discharge to the sanitary sewer.

  • Discharge wastewater to the sanitary sewer of the property where the cleaning was conducted with permission of the property owner. The on-site sanitary sewer can be accessed through a building drain, building sewer, industrial sink, private sewer clean-out, private sampling manhole, or any other privately-owned sanitary sewer access point. Discharges to the sewer should not contain grease, grit, or any material that could clog piping. Discharge to the sanitary sewer may also be required to be within a specific pH range. For example, under the jurisdiction of the MWRDGC, discharges to the sanitary sewer must have a pH of 5.0 to 10.0. Call the local publicly owned treatment works (POTW) for information on storm sewers and associated discharge requirements.


Wastewater belongs to the facility where it is generated; therefore, if the wastewater is not being collected and hauled offsite for proper disposal, the power washer must obtain permission to dispose of the water at the cleaning site. For example, at a gas station that also houses a car wash, wastewater from the power washing of gas pumps can be disposed of in the sand or grit trap of the car wash bay. At properly operated car washes, wastewater is pretreated by a sand filter and grease trap before discharge to the local POTW.

Do I need a permit for my mobile power wash discharge?

Power washing wastewater can be discharged to the sanitary sewer system with permission from the local POTW. Contact your local POTW to find out their requirements. We recommend you do not discharge your power washing wastewater to a septic system; however, if you plan to, you must contact the Illinois Department of Public Health.

Because mobile power wash regulations vary from city to city, it is wise to contact the city storm water program or department to determine exact permit requirements. For example, the city of Chicago requires power washers to obtain permits except for power washers that use water only. However, power washing used in conjunction with sandblasting to remove paint requires a permit by the city of Chicago. This permit is required because power washing can produce dust and potentially hazardous or harmful material.

How do I obtain more information?

For more information on mobile power washing, call the Illinois EPA Office of Small Business Helpline toll-free at (888) EPA-1996. All calls are considered confidential and the caller can remain anonymous.  In Chicago, call the Department of Environment permit desk at (312) 744-8026 for more information.