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JJBanjo
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JJ.
Welcome to the forum. Although you can post in any forum, the USA forum is here in case of local regs or laws
I'd take a guess at no proper shower trap and that loop is the trap. Fool of poop from the wc.
Reply to the thread, titled "Sewer smell from shower plug hole - dodgy air admittance valve? Pls view pic and help" which is posted in Air Sourced Heat Pumps Advice Forum on Plumbers Forums.
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