Dog Person – This person tends to bring their dog when it is not entirely appropriate, especially when it is an indoors setting, and then usually expect you to find space, water and sometimes even food for their canine compatriots.
What you might try – The dog is already at your place and you will have already been asked for water and space for the dog. If the dog becomes a nuisance, mention that subtly to the owner. If the owner still does not get the hint, suggest more directly that they remove the dog.