Residential vs. Commercial...
If y'all remember I owned a car wash in Michigan. Car washes, believe it or not, are considered "hazardous waste generators". The owners (and that was me!) had "cradle to grave" responsibility for everything ON the property. I was required to get an EPA Site License. The "sludge" that accumulated in the car wash pits, had to be removed by someone with the EPA and State license to do so, and they provided me with the report on each load, and what happened to it; once I paid them to do that, they assumed legal responsibility for it, and kept all the records.
What they did is suction out the water from the pits, and place into the city septic system. Then, the oily liquid and sludge was vacuumed out and hauled away. At their treatment facility, they put all of this into a centrifuge, and separate solids from liquids. The solids were dried and placed into a landfill. The liquids went through a separation process, the oils were collected and sent to a reprocessing facility (where they were eventually turned into the cheap SAE30 weight "white bottle reprocessed oil" you use in a lawnmower,) and the resulting oil-free liquid went into the city sewer system. In my case the hauler took this stuff about 100 miles away from my car wash. Cost me about $700 each load, every 6-9 months.
So, there is some EPA involvement at the local level, at least on the commercial side of things. Never saw an EPA agent but I sure saw their paperwork...