Venting Shower Drains for Dummies - The Freelance Files MMCIX

Many of the questions people plug into their search engines don't actually require much thought. Common sense – which is unfortunately rather uncommon in this day and age – would answer them if the OQ just thought for a minute. Nevertheless, the nice people at eHow.com snapped those queries up and sent them to their crew of "contributors" to answer; a crew whose grasp of common sense seems in retrospect to be rather tenuous. Take today's DotD nominee, returnee Steven Symes. Once again we find Symes pretending to know enough about plumbing to answer the question, "Do You Have to Vent a Shower Pan Drain?" for HomeSteady.com.

We said "once again" because this is Steve's seventh trip to the podium, and the fourth time he'd tried to convince people of his plumbing expertise. 

For the record, "Yes: you do have to vent a shower drain. You have to vent every drain in your plumbing system. Symes got that sort of right, waxing poetic about the dangers of sewer gas... which, when you think about it, is the reason that every drain in your system needs a trap as well as a vent.  Since Steven was required to pound out a certain number of words (300 to 500), he had to pass along more information. In addition to an obsession with sewer gas, Symes was a little shaky on how shower drains connect to vents: "Plumbing vent pipes connect to the drainpipes in your plumbing system, typically at the branch pipes. Multiple drainpipes feed into a larger drainpipe called a branch pipe, which then flows into the sewer drainpipe that connects to the sewer system."

Actually, none of his references said anything like that, although one did opine, rather illiterately, that,

"Vents are used in order to relief [sic] sewer gases, maintenance of the trap water sales [sic] and for oxygen admission [sic]."

In reality, every wet room – bathroom, kitchen, laundry, etc. – needs a vent pipe on the drain pipe that collects all the waste water. That's why houses have multiple vent pipes sticking through the roof. Symes more or less got that right, although with tortured prose. What he got wrong, and what caught our staffer's eye, is this crapalicious text:

"As you wash waste water down the drainpipes, that water may wash air in the drainpipes out of the plumbing system. The plumbing vent pipes replace the lost water in the drainpipes by pulling air from the outside into the pipes. Without new air coming into the pipes, the water in the traps in the plumbing fixtures may be pulled down the drainpipes. Without water in the trap pieces, the sewer gases in the pipes may flow up through the fixtures’ drain openings."

All that to say that vents prevent formation of a vacuum in the drain system. Sheesh... and to think our Dumbass of the Day couldn't figure out how to say that in one-fifth as many words! Pretty weak for an English Lit grad...

SE - PLUMBING