Why did my gray tank suddenly fill up?

[JosieNurse]

First trip in our 2017 AS interstate.
We were out all day in RV. We came home and I heard what sounded like a water pump running. Looked in the bathroom and the sink water was running fill blast and the sink was overflowing. I looked at the tank levels. This AM I filled up our white water tank and grey water only showed half full.
Tonight when I looked, the gray water was completely full and fresh water down about half way.
Why did this pap pen. Haven’t used any gray water at all today??

What caused it and how can we prevent this from happening again.
Thanks

[nvestysly]

Maybe I don't understand what you're asking. It seems like you've answered your own question. Your bathroom sink was on, water was being pumped from the fresh water system into the gray water system (the sinks and showers are on the gray water system).

I'm guessing somebody in your party left the bathroom sink in the off (trickle) position and didn't realize it. You left the van, the trickle became ON and presto - water is being pumped into the sink/gray.

To avoid this problem we developed a habit of turning on the pump when we need water and turning it off after we use the water. If the pump is turned off it cannot accidentally turn on.

With time you will determine a sequence of events that works for you.

On a related note... we never connect to city water and leave the pressure on when we leave the RV for this very reason. Over the years we've seen several people who have sprung a leak in their RV while away doing some shopping or sightseeing to return and find a soaked RV.

[JosieNurse]

Thanks forgetting back to me I think you are absolutely right. In addition, I have noticed that the handle on the sink isn’t very “tight” when it is pushed down. On out drive home I noticed that it had “raised up” a little bit. The pump was not on so there was no flood disaster! Maybe there is some way to tighten it up some !!