We have found that the only thing that holds up to dogs is Artificial Turf. We have used it on many back yards for dog areas and all of our customers swear by it. It is a 5-6 year investment compared to sod but well worth it. You will always have beautiful green lawn that the dogs can run freely on with no damage or dirt tracking back into the house. Here is the link to the turf we use the most. They can even help you out with a contractor to install it if you need one. www.ecowaterlessgrass.com