You could bubble large containers of water to remove the chlorine. It would require a pump for you to be able to pump the water out of the containers and deliver to your orchids, but you could do it. Take a large trashcan and install a couple of really good air bubblers. It should only take a day or two if the water is really bubbling.
The other way to deal would be to buy dechlorination chemical, but that would get expensive after awhile.
I hope someone here has a better alternative for you. Good luck.