Originally Posted by TexasBBQ
I've never had the underbelly to look at my tanks nor have I ever seen those types of tanks at a repair shop so I'm not familiar with the design. Are they vented other then the vent going to the roof? If it fills up does it overflow thru some outlet or will it just fill up the entry pipe until something leaks or bursts?
If you fill the grey tank all the way up, you usually end up with standing water in the tub/shower. The black tank would do the same to the toilet.
We have had our grey fill up once until it was backed up into the shower, but once we learned how to conserve and how long we can go before dumping, no problems