2002 Galant, floorboard on driver side completely soaked

check that the ac drain hose is not blocked . clean out the gunk in the ac box and ensure that the hose is clear all the way

ok first i would call the shop that just did the work odds are the drain tube is out of position when they reassembled the evap box

no it will most likely be a blocked drain pipe that goes into the engine bay from the A/C and drains the condensation created by your car's air conditioner. A mechanic workshop can do a blast of compressed air by your mechanic and free the blockage takes about 30 seconds to do with a car hoist.
If it is humid conditions the problem will be much more and you might find the front demister won't work due to water sitting on top of the Air conditioner. It will heat this water and blow steam on your window.

under the car there is a rubber drain tube you can blow compressed air in it to remove the clog.

You have a waterleak.
Possible locations.
Missing grommet on the bottom floor pan holes.
Door weatherstrip is not sealing door surfuace.
If you have a sunroof. the drain hoses from the sun roof down the pillar is nor connected properly. Do you see any watermarks on the head liner?

If you remove the door rails at the bottom of the doors you'll be able to lift the carpet and visually look for some small drain plug devices. It sounds like one or more of them is missing or that you have lost a seal in the door or window.

the ac drain is more than likley stopped up, they tend to get clogged with debri not allowing the condensation from the evap. core to drain properly, thus allowing it to leak into the floorboard.

Had the same problem with my 07 Galant.. the drain tube, which is on the bottom of the block and has an odd angle to it, is blocked with mold. If you can get it up on a life of get it on ramps, you will see a small tube sticking down toward the ground. Blow some compressed air into it and watch out, it will pour out!

The drain tube for the a/c is probably plugged. if you can find the tube where it comes out under the hood,usually on the passenger side low on the firewall. Use a piece of wire and clean it out. This should solve your problem.