Have a issue with drainage. Live in East Tenn with high clay. This is the problem... family of five. When it's bed time and bath tub is half full, drainage causes both toilets to gurgle. House bought 2 yrs ago built 1978 (had 2 people living in it ) and everything was great until last NOV. when the problem first started. Called the very next day for a complete pumping of the skeptic. As I stood there answering? From the poopie man... he said "this system never had been pump before". I asked how could you tell and he said the lids never been off. While the lid was off and the system now clean I had the kids inside the house drain the tub I had previously filled. As I stood there I watched the water empty into the skeptic with no gurgling :D everything worked as it should. This lead me to think the vents are OK. Both baffles in the tank were in place and not broken. I believe the drain field to be full now as it started 3 months later again and was hoping to divert tub and bathroom sink of one bathroom to washer drain which has it own skeptic tank on another building(pool house). Had my son with me under the crawlspace measure the distance which is 45 ft. Would 1.5 pvc set at 1/4" per ft.. be ok? It has 1.5 pvc now with a p-trap under the tub and 4"after the p-trap has it vent also 1.5 which is vented to the attic not out the roof as done today. Thought I ask for help because I see you can be very helpful. Thanks again

I would increase to 2" on the 45 ft. run. You stand a much better chance of a blockage with 1 1/2". Also I woukd revent the open attic vent back into the roof vent. The open vent is a direct connection to the septic tank and the sewer gas it expels. Sewer gas is harmful to your families health and the methane content makes it explosive if conditions are right. Regards, Tom