Black Water Tank Advice - Event Date: 26 Jul 2021

It is very easy to determine emptiness. Drain the black and gray tanks. They are guaranteed empty, no guesswork. Then fill the fresh water tank till it's completely full. Guaranteed full. Then go to your campsite. Don't connect city water. Use your fresh water via the pump until either it's gone or you leave.

When you leave for your next stop drain and refill as before, or drain and then refill at the next campground.

This procedure does a couple things for you. First, as StephenH says, you cannot overflow your gray or black tanks. Second, you cannot overload your trailer with too much water. Water is heavy and your trailer is not designed to handle the load of 3 full tanks (750 lbs). Using this approach you won't have more than 250 lbs total between the three tanks.

Third, none of the sensors have to work when you do this You don't need to ever look at the black and gray tank levels at all. You do need to monitor the fresh tank water level. But the fresh tank sensors are the most reliable, and if they do fail you can simply look at the water level in the tank under the trailer because it's translucent.

Thanks for all the great advice!  I think I'll unfasten a few feet of the plastic underlayer and use a flashlight to determine how the tank is installed and where the drain pipe is attached. 

If yours is like ours, the drain is at the front-center. So, level left to right and a little nose down would likely be best for draining. I'm not 100% sure on that model though. You would need to look.

We have a 2020 rPod 196 that we have had boondocking 4 times.  I'm not confident that the Black Water tank is emptying all the way at the dumping station.