Prior to exiting the foundation my main dwv drops approx. 13" then continues out to the septic tank. Is this enough slope to prevent any clogging if a running trap were to be installed? We've got an odor problem coming from the vents & I'd rather not extend the vents any higher or use the "odor hogs."
Thanks for any advice!

If the slope is working now a running trap won't make it any worse. If it were me I would rather vent the septic tank then install a running trap. How do you know the smell isn't comingfrom the house drainage system rather then the septic tank? Regards, Tom