During the past few years The Special Services and prison services have insisted that all vehicles used to carry dogs must carry water.
In the UK there is a special squad of twelve prison dog handlers that each have their own dog vehicle. The officers are on a twenty-four hour call to attend any prison in the UK where there is a riot.
All the handlers have special vehicles that are self-contained and are required to carry one weeks supply of clothing for themselves. They are also required to carry one weeks supply of food for the dog and one weeks supply of water.
Over the past few years it has been noted that the dogs when given water from other areas were not performing well and some had encountered either hyperactivity or under activity. Since the new ruling came into effect there have been no reports of change in behaviour.
I recommend that those that enter competitive work or dog shows should always take their own water. If you have a caravan and go away for a few weeks take water. If you are going for more than a few weeks then mix the local water with your own water on a 50/50 basis then your dog can be weaned with no side effects.