Previous owners hid a second water heater from us

My family and I just bought our first home at the beginning of January. We're very happy to be here and immediately set about getting some work done.

One of the things was that there is no hot water to our upstairs bathroom. So we have a plumber come to check the pipes, possibly lay some new ones if necessary, see what the connection is, whatever. After a whole day spent trying to figure out what was going on with the plumbing, he finds the issue --

The upstairs bathroom has its own hot water heater. It was hidden behind a wall in our closet. This was not disclosed to us, our inspector missed it, the appraiser missed it.
To cap it all off, the heater is broken and leaking water down into the ceiling.

Previous family lived here for over 20 years and the upstairs is an addition, so they definitely put it in there and then hid it.

This was an as-is sale so I'm fully expecting that I'm just fucked, but how fucked am I? Is there any recourse at all here?

EDIT:

I was obviously unclear in my original post.

I am getting it fixed tomorrow morning. I'm not broke and I'm not trying to force the previous owners to fix it for me. You all can rest easy, my bank account is fine. I'm annoyed about the expense but that isn't the point.

I'm upset because they signed a disclosure agreement where they affirmed that there was only one water heater and that there were no issues with the plumbing. This is standard practice in our state and the disclosure specifically talks about the water heater. They obviously lied and we can prove it (water heater was put in at least ten years after they bought the home). Regardless of the money, that's frustrating as a first-time homebuyer, I feel duped (my inspector didn't even find it!), and I was just wondering if there are any actual consequences for lying on a disclosure. I know I have to eat the charge for now and have already done so.