Saratoga Creek Dog Park is run by San Jose City and has just been updated. It was previously all dirt but now has Astroturf and a watering system. This park is great in the summer because it has mature trees for shade and the people are friendly. Some of them bring lawn chairs to share. We have visited here quite a few times. Just beware of the rescued greyhounds, they tend to be rough with small dogs (see the greyhound rescue sites for more information about rescue greyhounds at dog parks).