my parents have been dealing with this situation for years. their house was built with a workshop space under the garage floor. no drains. no idea what the prior occupants did over the winters.
after doing the squeegee routine for about 10 years, dad had a plumber drill out and plumb in a floor drain. it never worked right. Just created a new route for salt/water to seep into the slab, (we would have salt stalactites forming on the underside of the plywood tub the slab was poured into.)
tried umpteen different floorcoatings, all would end up peeling off, and the floor flaking beneath it.
finally, 2 years ago, dad decided to it was time to replace the floor.
the general consensus amongst the contractors was that a drain wasn't the answer, even in a new slab.
the answer is pitch.
the new slab is 4 inches thicker at the house end, than it is at the door end.
that and the slab needs to be a solid pour out past the door.
so it mostly runs off, but dad does still do the occasional squeegee, or shopvac... cuz that's who he is...