15 year old lab suddenly urinating in house

Question
Our 15 yr old yellow lab who has extreme arthritus has recently starting urinating in our dining room. She has started drinking alot more than normal also. Her appetite seems fine, and we were contributing this excessive drinking due to hot weather. Even though she is inside. She is getting up in the middle of the night now.
Due to financial reasons we cannot go to the vet very often with her, and if my husband finds out he will want to put her down. What do you suggest?

Answer
I have been spending a fortune on pain medicine for our 14 year old Lab.  At 15, if you can't afford pain medicine and other care. perhaps it is time to put her down.  Do you think she is enjoying life?  

It is possible the urination could be easily treated, but you would have to go to the vet.