we have 3 methods:
1. we know where all the streams, springs and water troughs are on our local rides. She will divert off to one of them when we are close for a drink.
2. She shares my camel back (or water bottle when on a short ride without the camelbak). She sees me drinking and comes over and I squirt it into her mouth.
3. On long rides I have a bottle fitted to the bike as well as the camelbak and she has that and I have the camelbak. I have a cheap, easier to squeeze bottle, for this as my normal podium bottle are quite firm and harder to really jet the water. It also doesnt matter if she licks it and I can refill them from sources mentioned in 1 as they are for dog only.
Also keep a stock of gravy bones in my camelbak and snacks we can both eat (ie no chocolate or raisins). Or she eats fresh horse poo when she is really hungry, at which point I offer her a snack out of my bag.
Oh and we have one of these: http://www.tazlab.com/v/vspfiles/V4_Backup/TL_bowls.htm
Use it on all day trips, especially if taking picnic or a couple of dogs. Folds up really compact and slips into an external/the net pocket on a backpack and gives the dog a more relaxing drink when you stop for a while.