Usually, I’m an advocate for keeping the water clean. When I was recently asked to help lead a training for City of Cottage Grove, however, I decided to call on my inner bad guy. The topic was “illicit discharge detection and elimination,” a sinister string of words that really just means, “stopping people from polluting the water.”

The stereotypical example of an illicit discharge is someone who pours a pan of used engine oil down a storm drain. Because storm drains connect directly to lakes, rivers, streams and wetlands, this causes water pollution that can kill fish and other wildlife. Other common examples include washing-off paint supplies and construction equipment in driveways and roads, dumping leaves and grass clippings into wetlands and ravines, and emptying swimming pools and spas into the street.

One of the challenges for public works departments at Cottage Grove and other cities is to recognize common water pollutants when they show up at the end of a stormwater pipe, and to trace those pollutants backwards to find their source. This is all a long way of explaining why last Thursday found me standing in the driveway, laughing maniacally as I poured gasoline, used engine oil, herbicide, paint, and soap into jars of water. The result? Gasoline smells bad and floats on the water; oil smells bad and floats on the water; herbicide is invisible(!); paint looks like paint in the water; soap is sudsy. Please don’t try it yourself!
So what should you do instead? Here is how to dispose of five common waste products:
- Used Engine Oil: Take used engine oil to a licensed local business, usually an auto parts store.
- Household Hazardous Waste: Old and unused paint, pesticides, cleaners, small electronics, vehicle fluids, batteries, propane tanks, fluorescent lights, and many other types of household hazardous waste can be taken to the Washington County Environmental Center in Woodbury (4039 Cottage Grove Dr.). Check the website for hours and details. Currently, the center is open Tue, Thu, Fri, and Sat.
- Grass Clippings and Yard Waste: Though yard waste is natural, it contains high levels of phosphorus and should not be dumped into storm drains, ditches, ravines, wetlands, or shoreline buffer areas. Instead, bag waste for curbside pick-up, take it to a drop-off site, or compost it at home.
- Chlorinated Water: Stop adding chlorine and leave your pool or hot tub uncovered for 48 hours to allow chlorine in the water to break down naturally. You can also purchase chemical solutions to de-chlorinate the water more quickly. If possible, empty pool water onto your lawn or a vegetated area so that some of the water can soak into the ground instead of running off into the storm sewer.
- Concrete Wastewater: Concrete is highly alkaline and corrosive, contains heavy metals, and is toxic to plants, fish, and other wildlife. If you are mixing concrete for a home project, use as little water as possible to clean buckets, tools, and equipment. Allow the slurry to sit outside on a tarp or plastic sheeting until the water has evaporated and then dispose of the leftover solids in the garbage. If you hire a contractor to install fence posts or pour concrete, make sure that they transport the wastewater off-site and dispose of it safely.

If you see illegal dumping or see water coming out of a stormwater pipe that is cloudy, colored, or has an oil sheen, report it to your city’s public works department.
Report petroleum and hazardous materials spills to the Minnesota Duty Officer: 1-800-422-0798