2007 hot water heater leaking

look for leak --clogged line --or problem with pump

Have you checked back of water heater for proper valve positioning? (by-pass may be on)
Cold water enters through bottom fitting and hot comes out the top. Any valves in between should be closed and any valves going in bottom and out top should be open.

I do not know the answer, or exactly which part is best to replace.
I would order all affected parts and have on-hand when work starts, otherwise you might be half done after a day of repair.
There are numerous blogs and self-help resources about atwood water heaters.

The following resource can help identify exact model number and part number for your specific heater. Plus maintenance tips.
The number of parts available and ez access to sellers of parts indicates these water heaters are frequently down, but are fully repairable.
http://waterheatertimer.org/Atwood-water-heater-resources.html

Upvote the help.
And take advantage of fixya expert assistance live.
For a price, expert works with you while you work on timer or any do-it-yourself project.
Fixya is always less expensive than a service call.

Check your by-pass again. Cold water enters bottom fitting/line, and hot comes out the top fitting/line. Any valve in between should be closed, and any valve going in at bottom should be open, as well as open at top. There are a few different by-pass set-ups, so without knowing which one you have, this should guide you somewhat.
If you can describe what you see there, I can probably guide you through it.

Make sure flame is good under thermocouple probe so that it gets proper sensing of flame, and if that's o.k., before you change gas control, remove thermocouple fitting where it attaches to gas control and spray wd-40 in the hole and twirl up some steel wool and push it in the hole and twirl it to try and clean the surface inside there as well. Then spray it out with WD-40 once more to flush out shavings etc, and if you have compressed air, blow it out as well. Now re-attach fitting and snug it, then re-try pilot again. If it works, great if not replace gas control. Let me know the results. You do realize that it should be a certified technician who changes that gas control if necessary, correct?

The two switches control the water heater either in the gas or electric mode. The switch with the lights would be for the gas operation, and the switch without lights would be for the electric mode. Prior to operating either switch, make sure the water tank is full of water. Turn your hot water tap on, if water comes out, tank is full. Connect trailer to 110 Volt source, turn circuit breakers on, Place switch without lights to on position. If water does not heat in 45 minutes, Install new heat proble. The gas mode should be repaired by someone that is familiar with that system. Atwood can provide you with a local service center.

Check for by-pass valve(s) on back in wrong position(s).

Have you checked your by-pass at rear of water heater to make sure it's in proper position? If it's still in bypass, you will only get cold water from either tap. Cold water goes in bottom, and hot comes out top. Any valves in between those 2 lines need to be off. Let me know what you find, as they use a few different ways to do the by-pass.

Check that the by-pass valve(s) on or near back of water heater are in the proper position. If your stumped on how they should be for normal operation, remember this. Cold water has to flow into bottom of tank, so that valve needs to be open straight into that fitting. Then the hot comes out the top, so that valve has to be open as well. Any valves in between those lines need to be closed, otherwise it will mix cold and hot . If still not sure, get back to me, with location of any valves there, and I'll guide you through it.

Where is it coming from? It would make sense to have a plug in the conwe of the tank. Need you to clarify what it is lthat is leajing.