Who was it that had a problem with water..

[Ozz]

The leakage in a 3400rl around the steps leaking onto the vinyl????
I can't find your post anywhere.
You asked about what a vacuum breaker was, I have info. on that topic.
Also, I wanted to tell you that I added water to my fresh water tank with the valve in the service bay, my vacuum breaker stuck up behind the shower, I guess, (there is one up there somewhere, maybe other members know about it)because I had water all over the floor by the steps, may be the same problem with yours. I know you stated it happened when raining, but this may be concindence...
Here are some links for you.
(Besides, I think you offered a quarter for the solution...)
http://www.filterchem.com/vacuum-breaker-valves.cfm
http://www.watts.com/pro/_products_s...=65&parCat=102
http://en.wikipedia.org/wiki/Atmospheric_vacuum_breaker

[sreigle]

I've had water come from under the steps three times. Three different causes. One was loose connections behind the convenience center panel. One was loose connections to the shower faucet (under the shower floor, accessible through those access panels and yes it ran down under the stairs). The other was loose connection on the water pump, similar to the first problem. All three resulted in water in the same exact location coming out under the panty/stair area.