Plumbing Questions? Ask a Plumbing Expert.
hi I am dan I can help you with this. first thing I think of for this is you have a valve that is leaking and it is piped into the drain. you have a valve like this (the lower picture on that page) on the tank somewhere and it will have a 3/4" pipe coming off of it going to the drain. if you follow that pipe to the end let me know if you see water coming out of it.