Have a question regarding function of this in-line P trap. Does this look like a proper plumbing job? The vent stack is to the right of it. And the washing machine and vanity are draining from the left, the vanity does have a p trap but I am unsure if the washing machine does without tearing out drywall. I get a strong odor of sewer gas from the washing machine drain only and was unsure if this p trap was adequate to prevent sewer gas backdraft. I noticed the bathroom van was vented out the roof stack and was getting sewer gas from that as well, I recently changed that to it own location out the roof which leads me to believe there may be other mistakes with this plumbing job. Thanks for your help.