Has anyone ever had this problem.....

Folks, this ain't go nothing to do with the guages.

99% of the gauges are wrong,


X2X2, my guages did not read accurately from the day I picked up my new trailer:):)

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He was measuring to see how much water the tank held.

I gotta ask........why refill them after draining?

Gauges have nothing to do with it...he filled black tank until water was almost coming into commode...gray tank he filled until it started filling the shower pan....

The gauges are typically marked in 1/3 increments. So, with a 42 gallon tank, 15 gallons would move it past 1/3 full to 2/3s full. 29 gallons would move the gauge past 2/3 full to full. In the case of your BIL, maybe the tank didn't empty out completely (TP, poop, etc), accounting for the 3 gallon difference. But, I believe, when he hit 26 gallons of added water, he still had about 13 gallons of space left. I could be wrong, but that is my experience with the two tts I have owned.

I find it much better to be warned before I am full than after...

Some trailers have two separate gray water tanks one for the galley and another for the bath. My Passport has two thirty gallon tanks (paperwork says 60 gal) and the DW can fill the bath one in a couple of showers. We have a 35 gallon tote tank so I just make trips to the dump station, got to keep the DW happy.

By "full," is this based on the gauge, or water no longer draining?

If based on gauge, notoriously error prone, I don't look at mine. Only time wife and I have filled bathroom gray tank (water standing in shower stall) was after 6 showers when not watchful on duration of showers. Have never filled black or galley gray tank during these 3-day trips. For the week of Spring Break, we will dump tanks middle of the week and again before heading out.

If water no longer draining into the tank ... hopefully others can help!

99% of the gauges are wrong,