I am currently building a new home. The access to the septic tank from the back of the house is currently blocked by the home we are currently living in. I am wondering if it is feasible to put a 90 with a clean out at the house and another further down to direct flow to the septic tank. This was at first intended to be temporary but if not totally out of the ordinary and functional could be permanent. Looking for some advice.

I am wondering if it is feasible to put a 90 with a clean out at the house and another further down to direct flow to the septic tank.
Don't use 90s. Use long sweeps or two 45s and place a cleanout at each bend. Give the line 1/4" to the foot slope. Good luck, Tom

If you live in an incportated area or place governed by codes you will need the county or local inspector to Ok you idea. How many bedrooms were in the old house and how many in the new house? Do you know how many gallons is your current tank? Tom is so right, the stuff we flush doesn't like to slam into 90 degree elbows.