How Do I Know When My Tanks are Full?

hershey wrote:

The gauges on the tanks were designed by an evil mind who gets great satisfaction in having RVers spend hours and money on trying to get them to work.

To this I heartly agree!

In my coach, the kitchen sink also goes to the black tank and not the grey so it is the one that normally fills first. That makes it easy as all I have to do is look down the toilet and look at the level. Someday, I will deal with the level lights that occasionally do something.

I do agree with the above statement about not over filling as a loose connection on the top of the tank is not normally an issue, but will rapidly become one if you fill to the absolute top. We have enough issues with these coaches without creating more!