We started our dig a few days ago and of course we had to change direction after running into septic line. we are from pittsburgh and so this septic thing is new for us we had the plat overlay but it was off .. Just watching the dogs dont fall in the hole or get lost in the mountain of orange dirt . We wont get to use it now until next year but figured we will be ready to go next year. we did the 18x 38 rectangular with a crystal liner . the liner was the hardest part . Now i just have to order the test kit . oh and can someone tell me if we order a safety cover do we order an 18x 36 in the cover .it sounds like they go over an extra 2 feet so am wondering if we need a 20x40 ?