I personaly do not know how Colorado works their city water and waste.
In N.Y.C. you were allowed to have a well,many buisnesses did for when there were drought restrictions on city water.And septics were not allowed due to the space required by code,unless of course you had sufficient space to meet code requirement.

I would think that they would permit certain buisnesses In Col. city limits to have wells so not to strain the rest of the water supply,just makes sense to me anyways.