Most household and construction debris is fine. The limits come from the rules at the Salt Lake Valley Landfill, where most Millcreek loads go.
The landfill doesn't accept solar panels or battery systems at all. Tires are capped at 12 per load, and oversized equipment tires aren't taken. Mattresses are accepted from homeowners, but business loads of more than six pieces need other arrangements.
Paint, pesticides, fuel, batteries, electronics, used oil, and antifreeze belong at the county's household hazardous waste facility. That drop-off is for residents only, not businesses.
Hazardous waste, liquids, solvents, and asbestos can't go in a standard dumpster.
If you're unsure about an item, ask your account manager before you load it.