I’ve got to go diving into our lake behind our house as an pipe or something is clogged under there, Should i tie a rope onto my waistline while I’m deep in the water while diving ? I’ll be using an mask, scuba tank & some swim fins.

A rope tender only adds another entanglement hazard. If you are not properly trained, then this is making a dangerous situation more dangerous.

Second, are you properly trained for scuba diving? If it is a standard recreational diving certification, are you diving with a buddy?

If you are trying to dive solo, are you properly trained for solo diving? Since you lack a buddy, you have to be completely self sufficient while diving.

Back to the rope tender, the only diving that I know of that uses are rope tender (and a live person at the other end) are ice divers.