Best tutorial I've found for a diy Potty Patch. It includes a slanted drainage system with a hose that you can feed directly to a drain. Rinsing once a week with water and bleach is all the cleaning it needs!
How to make a doggie potty on an apartment balcony. http://superdogcharliepants.blogspot.jp/2011/06/dog-potty-for-patio-build-your-own.html
Amazon.com : Fresh Patch Disposable Dog Potty with REAL Grass - As Seen on SHARK TANK : Pet Training Pads : Pet Supplies
I made this doggy potty island out of kiddie swimming pool, palm & 3 pallets of sod for doggys with limited yard opportunities!!!
Porch Potty is Amazing - First Automated Dog Litter Box