disclosed in seller disclosure, then you need to prove that the sellers had knowledge of the leak, but chose not to disclose. if the sellers truly had no idea, they can't be held responsible. the inspector cannot see behind the walls, but if there was obvious water damage that he did not catch, then you could question why they missed it. how did you find out about the leak? the township does not handle disputes between buyer and seller.
best to contact your realtor and attorney and see what they advise.
I am not an attorney, but rather I am answering from opinion and experience.
There is no one to "fight". You bought a home and had a home inspection. It sounds as if the seller did not know about it either. It happens. There are things that go unnoticed until a problem surfaces. If there were no visible signs, it probably got past your home inspector also. I do not think your words of the inspector "not disclosing" the leak is accurate, rather he not discover the leakage.
Most inspection reports read that the home inspection cannot tell you what is happening behind walls. That is why I recommend a home inspector that has one of those "guns" that detect water behind walls..
No one at the township will be able to help you. I guess you can ask your attorney for help, but it sounds to me like it will not be a viable complaint. You did have a home inspection and it is quite possible the seller did not know about it either.
. Good luck to you.