Do you carry water on your walks with your dog?

Apparently, the welfare law for pets is going to change so there must be a constant supply of water (if anyone can offer me a link to anything to do with this, that would be a great help) & I just wondered; how many of you bring water on all your walks with your dog? It is something that never occurred to me. I only walk to the park with mine & she gets all she wants when she gets home.