Hi Jayne, I have twelve dogs (ten bitches) who are watering my lawn and yes it does get brown in places but the heavy rains this spring have revitalised our grass and all is green again for a while (middle of hot spell) We do not treat our grass with anything, no fertiliser nothing. Its only grass and my dogs health comes first:-)
If your lawn area is small and you have nice shrubs (probably won't have those for long as Berners are avid gardeners and landscapers:-) then you could make an area to train your future puppy to toilet on. Two of my puppy owners made an area covered with peastone and for the boys put a tree stump for them to lift their leg, worked great and the lawn stayed green. Hose down and javex once in a while and all stays fresh:-) Do not feed any products to the dog that are designed to change the Ph of the urine, that is potentially harmful to the dog. Rose