Water Tank Lesson-long read but could help you
I learned the hard way that you should never fill your water tank to the brim prior to a dry camping day out. I normally only load up about 25 % with water, enough to flush etc.
This day, I filled it by accident, right to the brim. I inserted the water hose into the tank fill neck but walked away from it only to realize later that it was full and spitting out the inlet. When I removed the hose, a jet stream of water gushed out.
I thought no more of it until later in the day, after driving about 200 miles, I had wet spots on the trunk carpet.
I removed the mattress and plywood cover and immediately discovered what caused the wetness. First, here is NO overflow drain relief. (Is this normal not to have an overflow drain relief?)Second, the 1 1/4" plug was wrapped with teflon tape but loose. Water was still dripping from the connection. I re-wrapped it with new tape and when re-threading it noted I could not fully tighten the plug. It just wants to keep threading, but not really make a good water tight seal.
Refer to attachment picture. Should I install an overflow drain? Do I need a need new 1 1/4 " plug that would make a tighter seal? Any other advice would be appreciated. Thank you.
2003 Land Y. Gas