Hello - I have water coming into my camper (onto the bathroom floor which then proceeds to leak into my bedroom) when I flush the black water tank from the outside hose hookup. I have a water pressure regulator on the water spigot. I have read that perhaps a cracked anti-siphon valve might be culprit. Does anyone happen to know where this valve is hidden?
Thanks for the advice. I'll look although there is only one sink cabinet and I don't recall any valves under there. There is a plastic access plate on the front of the shower as you step into it. Maybe I will open that up. We winterized and even flushed out the holding tank a couple times since de-winterizing in April with no problem. But that wasn't the case a couple weekends ago.
I'll continue looking. If you can think of any other common reasons why this might be happening I'm happy to hear the suggestions.
I did hear of the vacuum breakers being installed behind the shower, so that is worth a look. If you are talking about the access plate near the floor, you might be able to see a hose or two, and even see where the water is coming from, but a vacuum breaker would be several feet above floor level. Some are accessible by removing the shower valves and looking in the resulting hole.
My trailer is different than yours, but I found my vacuum breaker by removing the kitchen drawers. When I said cabinets, I meant any and all, not just in a bathroom. The most likely place is somewhere near the outside connection, but it doesn't have to make sense.
Many fittings are installed poorly in RVs, workmanship can be horrible, so anything is possible. A pipe or hose can be loose, crushed, broken, stapled or have a screw driver thru it.
Just to clarify the winterizing process, did you pump anti-freeze into the black tank flush connection? That system is in no way part of the fresh water system.