[Russ]

I have an older home, circa 1960, with a poorly designed drain system. I have no vent lines installed. I have seen a device called an auto vent. Is this a safe solution to my vent problem? Also, at present, I have a stopped drain in my 4" line. What is the best auger to use? I understand that the small versions offerd by hardware stores are to be used only with small diameter drains. If I rent an auger, what type should I look for?