This is less than 1.25 cubic feet of dirt, less than 10 gallons of compacted dirt. Not much more than one decent post hole! I have seen the time I would dig your hole for $1.00. Buy a 2 pound hammer, a large cold chisel and get busy. Or hire an ex-Marine who has seen combat! Foxholes are dug quickly under fire.

If you don't really need it and just need if for a dehumidifier, a sump box sounds a lot easier to me.

I just dug a hole for a sump 26 inches deep and 24 in across the top. Used a HILTI drill/hammer. Was a piece of cake. I drilled the holes around the circumferance first then changed the setting to hammer put on a point bit and in no time had her done. Then put on a 1 1/2 in. concrete drill and drilled through the poured concrete wall for the drain pipe. Mind you I borrowed the HILTI but you could rent the same . The worst part was carrying the debris up the stairs.

Thanks! I guess I can try again. I rented a drill for $75. Used it for 1 hour and barely got the hole started. I got the 3 inch bit with the drill and a chisel as well. The hole is in a tight spot and I forgot to get earplugs. VERY important to get plugs! I literally couldn't keep drilling in the spot and not have my ears hurt. After seeing the concrete was several inches thick, I gave up and thought I'd get a 'specialist' to take care of it. I still haven't gotten past the concrete surface. I figured they would have a specialized tool or something.

I may try again (with earplugs!)on my own someday. I just thought if it were cheap enough, I'd get it done by someone else. thanks again.

A REAL drill is important. I fought predrilling for my Tapcons using a lesser drill. Literally FOUGHT. I was nearly in tears a few times. I rented a Hilti and each hole took about 15 seconds.

A rotary hammer is by far the better choice. A hammer drill will be much slower. They often look similar and are not clearly distinguished from each other even by the rental places. The big 3" bit is expensive and is of no benefit. A 1/2" bit used to make multiple holes is better and faster. I do, in recent years, own such equipment. But if I did not, I can cut through that concrete with hammer and cold chisel in less time than the round trip visit to the rental place.

Even a hammer drill should be able to punch 1/2 inch holes through concrete pretty quickly.
A rotary hammer will go through it like butter.
You should make the hole a few inches larger than the liner for the pit so you can repair the cut edge and still have the hole size you want.
Drill a series of 1/2 inch holes around the perimeter of the opening you want.
Use a cold chisel and a drilling hammer to break out the web between the holes.
The closer you can get the holes to each other the easier the hand work.

It was a piece of cake like I said with the HILTI. I drilles 1/2 holes around the hole then attached a point punch, much easier than a chisel attachment.Seems like the rental people aren't up on comcrete drilling. Too bad they didn't give you the proper attachments. Don't give up. Even with a return trip it will be a lot cheaper then hiring someone. Kepp us updated.