My yard sprinkler system has had several cracks in the PVC pipe over the years. Used to dig a big hole, cut out the pipe and put in a new piece. It was thin wall pipe, not even schedule 40. House builder saved a penny or two.....
One day I bought some Epoxy putty designed to be used on PVC in wet conditions. I applied it over the offending crack and let it sit for 24 hours. That was a couple years ago and it and a couple more are holding fine even with 80lb of pressure.
So go to Lowes,etc and get the Epoxy putty, it will do the job.