Full of sheet over here

Having plumbing problems broskis. Every time it dumps 1+ inches of rain, my septic starts to back up. Usually takes a few days to recover as long as the rain holds off. I have to plan large dumps accordingly and use dash wipes to bathe when this happens. This isn’t a cheap neighborhood either...shouldn’t have to deal with these third world sheethole problems.

I do have sewer in my area, and have been told by some that it’s illegal to repair my septic and that I have to tie on to the sewer. Anybody ever heard of such...and whats that cost!? Also, should I take the plunge and flush the idea of fixing my septic down the drain? Pros/cons...halp me brahs...my bowels are churning.