ml1337
New Member
I'm in the market for a softener and have discussed options with professional installers. One of them told me that he was going to install a standpipe and a p-trap off my main 4'' drain pipe in the basement (photo attached). I asked him what he had planned for venting this trap, since the nearest vent is on the other side of the house and buried in a wall upstairs. He said the standpipe didn't need venting. I asked for details since I thought all p-traps needed venting, and he gave me some weird explanation about how the air gap was sufficient for venting the trap. That didn't make sense to me. But I don't know all the ins and outs of the plumbing code so I didn't insist. I figured I could turn to this wonderful forum for answers... So... Do I need a vent for this softener standpipe, at least an AAV?
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