Crack in fresh water tank

[Jeff August]

Hello to all!
We have a crack in our street side fresh water tank, it is about a inch
or so long about half way up the side of the tank. What do I use or how
do I fix this, it is a plastic tank. I will try and see if I can lift
it out some to get at the crack, will something like Permatex work?
Thankyou for your help!
Michelle and Jeff August
1980FC35RB
Plymouth Wi.