Cast iron drain pipe replacement/lining

[stav]

I thought I heard somewhere that the plumbing codes require one trap per basin, rather than one trap for both basins, but I'm not clear on the logic in that other than knowing which trap has the clog when one basin backs up.  A disposal does, of course, need to be upstream of a trap.


And I wouldn't worry about it, if it were me.  Jillions of two-basin sinks have just one trap.

We're on septic so we don't have a disposal. I've looked up several instructionals, including one from This Old House, and none used a p trap for each basin.

[Snipe Hunter]

He also said our kitchen needed a double p trap in the piping from the sinks to the drain. Gotta look into that. The logic is lost on me.

[Robert Adams]

We're on septic so we don't have a disposal. I've looked up several instructionals, including one from This Old House, and none used a p trap for each basin.

           I did ours with two just cause I wanted to and if someone plugs up one trap the other basin will still drain... I have a disposal but it's a super crappy brand waste king horrible junk thing(king of waste of money it is). The rubber flaps are very poorly designed that they cause an air bubble to block water flow out of the sink. One of these days I will pop it out and punch a few holes in it to allow it to flow better. It rarely gets used but I will never stray from insinkerator again... Or if it ever dies I may just omit it.

[Bob10]

If you sink is in front of a window it may not be vented to allow for enough air to flow properly.  My sink has what the call an island vent it allows for not having a vent directly above and keeps things from slowing down.  As for the liner out here it is fairly common and while not cheap it saves having tear open a house and landscaping, either of which could cost several times what the liner costs.  For my house I replaced the entire line before remodeling then again I have a raised foundation and the hole digging was all me as was placing the pipe.