Monsoon Rain System Drainage Problem

So I have a 18 x 18 x 30 medium Reptibreeze for my juvenile veiled chameleon, and I am getting a Monsoon Misting system from Exo Terra to switch out with his dripper. My only problem is the drainage,I don't exactly want to ruin the wall behind the cage and the floor beneath. Any suggestions?

The only way I could set it up to have NO water outside the cage was cover both sides and back with plastic (I use panda plastic) spray nozzles towards the back and sides (I use 3 nozzles) and use a drip pan (I got mine from 3L) Lean it all the one back corner with a drain. Now I can run my mister as long as I want and I have 0 water outside the cage.

As Lazy Boy said or stand the enclosure on some sort of raised up frame so that you can make a drainage hole in the bottom and have a tray underneath to catch the water.

I created "splash panels" out of corrugated plastic card board stuff that I found at Lowes right there near the plexi-glass and plate glass area. I velcro'd them on the first version, but I found I should probably screw them to my frames for a better install.

Then you always want to get creative on a drip pan. There is a great thread that has been going on for sometime w/ lots of great versions.

https://www.chameleonforums.com/drainage-systems-cages-get-creative-102038/

Where did you find 18"x18"x30" Reptibreeze cage? I know of the 16"x16"x30" and 18"x18"x36" cages, but not the former. I would like to replace my 16"x16"x30"s with the 18". Thanks. (I have a suspicion you combined the sizes by accident or misread. This could lead to purchasing the wrong sized drain pan, if you do. I use coroplast on the back and needed sides, held in place with window screen latches)