Dog Potty for Patio

Now that Paul and I have moved to Colorado, I don't know if I mentioned that but yes Paul and I now live in Denver, Colorado, we live in a townhouse without a yard, which means every time the dogs need to do their business we have to take them outside.  It isn't so bad now, but I am sure soon enough if might get annoying especially since I am used to just opening up the back door and letting them run wild in the yard.  So I googled "dog potty for patio" and found this amazing device called the Porch Potty for Dogs. I am not sure if we will buy this or just make our own version. Check this thing out. It has its own fire hydrant and sprinkler system. This is very similar to the potty stations in the airports.