Problem with popcorn ceilings is they start to deteriorate starting at about 12 years so far as I've been able to tell.
I did a lot of popcorn removal & ceiling refinishing on our last house that we remodeled from top to bottom. Messy, tedious, thankless, job - and I hate working on stuff that's over my head for extended periods. But it can be done. Use a pump sprayer & spritz water on the ceiling a section at a time. Let it soak in five or ten minutes then the popcorn should scrape off with a flat scraper (mounted on a pole works best.) Then you can re-texture the ceiling (without using popcorn) after you've got it all off & relatively smooth.
Never again for me though. In hindsight I'd probably have been better off just to tear the drywall itself off the ceiling put new up, and call a crew in to finish & texture it (without using "popcorn"). Finishing and/or texturing a ceiling is a bit of an art/skill I've personally never mastered .... in the future I'll be happy to pay those who do it everyday.
I heard u can lightly spray a mist of water on it then scrape it off. Moisture causes it to fall normally. It falls in the garages, & in showers mostly. Usually caused by lack of proper kilns treatment before spraying the pop corn.
Major prep and a pump sprayer is what works the best.. Take plastic and cover the floors, the walls from ceiling down.. Unless you want to clean the old popcorn/mud off the walls.. Take a pump sprayer and spray the ceiling really well and take a 6inch or bigger flat sheetrock knife... You will gouge the ceiling and probably take off some sheetrock mud tape... Then fix whatever got messed up and spray texture or knockdown back on...
I am a do-it-yourselfer in most cases but I think it would be best to hire this out. I did a small test area with the spray, soak and scrape and although not too difficult I also hate working overhead and this may be the messiest job out there. I found some some ppl online coming to give a price so we'll see.
Its not that hard to get off, just wet a bit with a pump up or hand sprayer a little vinegar in the water makes it easier.
Put down throw away plastic drop cloths and then cover them with paper, use a sheet rock knife to scrape and when you are done roll up the stuff on the floor. If some gets on the walls scrape/wipe it off immediately, if you plan to paint the walls then just hit it with the knife and move on.
It is messy, really messy. You would want to move everything out the room you are working in my opinion.
Once the popcorn is down you will probably have to put a skim coat on the ceiling then, sand prime and paint.
I know a guy over here in OB but no one in Pcola that does this work. Cost me a little over a $1 a square foot for the skim, sand and prime. I did the scraping.
I do it quite often as a sheetrocker. I work for a major remodeling company here in town but I also do side work as well. I can removed it with little mess, repair and re-shoot with orange peel. I'll be out of town until the 13th, but would be happy to come take a look at it, explain the process, and give you a free estimate when I return.