On 12/17/2013 10:11 PM, Tony Hwang wrote:


Don't forget floor drains in the basement. They may or may not be
connected to the sewer.


Actually , if the drains are properly vented there's no way a
vacuum in
the system can suck the p-traps dry .

Hmmm,
According to law of physics, I'd say. Any thing can happen to any thing
any time.

According to the laws of physics, perhaps you're correct. Highly
unusual for it to occur though if the caveat "PROPERLY VENTED" is accurate.

I wonder though if the city was actually cautioning him about the storm
sewers. Floor drain in the basement is generally (again GENERALLY) not
supposed to be tied in the the sanitary sewer line which is vent,
however it if is -as may well be the case here (hence the city's
concern) - I don't think that that sewer drain is tied into the vent
stack in the house. Perhaps it's supposed to be but I've seen too many
where it's not.

If I was the original poster, I would check to make sure there's water
in the p-traps and if I wasn't absolutely sure that the basement drain
was NOT connected to the affected line, I'd install a pressure plug
until the crisis passed so that whether they suck the line clear or try
to blow it clear, the crap would take the path of least resistance and
not fill up my basement.