The 20-yard is 16 feet long with 5-foot walls and 3 tons included at $449. The 30-yard is 20 feet long with 6-foot walls and 4 tons at $600. Both are 7 feet wide, so the driveway question is about length, not width, and four feet is usually the difference between a dumpster that fits behind your car and one that does not.
Here is the rule Devin gives on the phone. A kitchen or a bathroom, a garage, a roof up to about 30 squares, one or two rooms of furniture: that is the 20-yard. A full-house cleanout, a demolition, a roof bigger than 30 squares, or a job where you do not know how much is in there: that is the 30.
The reason the 30 wins ties is arithmetic, not upselling. A second dumpster is a new rental at full price, because the truck makes the trip twice. If you rent the 20 for $449 and fill it, the 30 you should have taken would have cost $151 more. The second 20 costs another $449. Every person who calls back for a second dumpster would rather have gone up a size, and nobody who went up a size has ever called to complain about the extra room.
Weight is the one place the bigger dumpster is the wrong answer. Both sizes come with a tonnage allowance and $60 a ton after it, weighed on a printed scale ticket. Concrete, brick, dirt and shingles are heavy enough that you reach the truck's legal hauling limit long before you reach the top of a 6-foot wall. On those loads the extra volume is room you cannot legally use, so the smaller dumpster and a frank conversation about tonnage is the cheaper outcome.
Devin owns more 30-yards than any other size, which is a practical point rather than a sales one. If you need a dumpster tomorrow, the 30 is the one most likely to be sitting in the Woodruff yard.
One more thing that catches people. Wall height changes how you load, not just how much fits. Six-foot walls mean you are lifting drywall and furniture higher to get it over the side. If most of your load is heavy and awkward rather than bulky, the 5-foot walls on the 20 are genuinely easier to work with, and the Space Saver exists for the opposite problem, a short driveway that needs the volume in a 12-foot footprint.
Driveway length is the constraint that decides this for a lot of people before capacity ever comes into it. Sixteen feet of dumpster plus the room a truck needs to back in and roll it off means about sixty feet of straight run. Twenty feet of dumpster means the same sixty feet, but the dumpster itself eats four more of them at the top. If your driveway has a turn, a carport, or a car that has to stay parked, measure before you decide, and mention it when you call so the driver can look at it on the placement call rather than in your driveway.
The other thing that separates these two in practice is what is in the yard. Devin owns more 30-yards than any other size, so on a two-day timeline the 30 is usually the one available. That is not a reason to take a size you do not need, but if the answer is genuinely close and you want it Thursday, it settles the tie.
A note for contractors, who are about seventy percent of DJP's work. On a job running weeks rather than days, the 30 with a swap partway through is usually cheaper than two 20s, and the swap gets scheduled on the phone rather than through a portal. Say what the job is and how long it runs and Devin will lay out both numbers.
Not sure after all that? Say what the job is on the phone and we will size it. Call 864-881-DUMP.