Black water tank on my previous rig developed a 4-5" long crack in the recess behind the drain connection. Was up in Indiana. Went to Home Depot and bought several large tubes of JB Weld. Sanded the crack, put on 3-4 layers of JB Weld. Used rubber gloves to smooth on areas that the putty knife could not reach. Drove that 5er for 5 more years and 40,000 miles without another leak. Tank was black which indicated it was ABS. JB Weld will not stick to the white colored tanks if they are Polypropylene although I have heard that there are now adhesives that will.
