How deep is it below the ground right there?
Good plan about exposing the pipe and while you are at that install a new 2 way clean out near the front post and cap and bury the old one. 2 types of fittings.Yes an access panel - one of the stair steps maybe - is a good idea. I've never seen a tank being cleaned and ignorant of what kind of issues blocking free access (the way it is now) for a septic service might cause. (Like double price for difficult access issues?). @Nealtw - IDK how deep it goes down. I'm thinking I will need to uncover the entire pipe and tank to make sure I don't cause problems with placement of my deck posts. Yes waterproofing before raising the ground level is part of the plan.