Gray Water Overflow Danger

Try not to make this mistake! I only drain the black tank (the main sewer tank) about once a week. When I do this I close the gray water valves. One gray water valve goes to the kitchen sink and the other goes to the bathroom sink and shower stall. I close these drains because if I don’t the smell from the black tank filters up through the gray lines and into the coach. Not pleasant!

When I had finished dumping the black water tank, I closed the black water tank valve and went back inside and washed up. OK, so what’s the problem? Well, I forgot to re-open the gray water tanks so that they would continuously drain.

We took showers and my wife did several loads of laundry. Luckily I opened the shower for something and found that the shower gray water tank was completely full and had backed up into the shower to the point that it was about to overflow.

This would have been quite a mess – all because I forgot to re-open the gray water valves. Fortunately for me I avoided a night in the doghouse because I caught it in time.

I wanted to show you this shower basin so you can see how it is constructed. You see the lip around the edge? This lip raised about one inch above the crown of the shower basin. The wall of the shower comes down over this lip and water run-off is prevented from seeping behind the shower wall. My RV tech told me that no caulking should be used between this lip and the shower wall. The reason is to allow air to circulate behind the shower wall and aid in preventing the buildup of moisture. So, you can see that if your gray water tank backs up it will overflow your shower stall and make a huge mess. Here is an idea that I am going to try in order to remind myself to re-open the grey water valves. I am going to put a ball chord bungee on my wrist when I open the valves and won’t take it off until they are re-opened, then I will wrap the bungee around the valve handle. Hopefully this new procedure will do the trick. Jim