how is it possible for a shower drain to back up and flow out of a kitchen faucet?

Question

i'm in a 2nd story apartment in a 2 story building. i cleaned my shower with comet one night. the next morning i go to the kitchen sink and when i turned it on there was a pause like air in the lines and then the greenish water that went down my shower drain the night before came spitting out. i understand that many sinks / tubs all drain to the same place, poor ventilation can cause a back up, but my question is how can the shower drain possibly be linked to the incoming water supply

isn't the incoming water / outgoing waste water completely two different systems that are not ever linked

Answer 1

Are you absolutely positive it was the same water? If someone was working on the pipes or water pressure was lost in the night, there would be air in the lines and usually a lot of crud that has settled in the water lines will blow out when it's first turned on (it can look pretty nasty). If you think the drain-water line cross connection is real, first, try to re-create the incident; run some water with food coloring or something in it down the shower drain and see if it appears at the sink ther next morning. I think it was just some kind of wierd coincidence. Even if somebody through igrorance (or on purpose) connected your water lines with your drain lines water would just go directly from the water lines down the drain lines; you'd hear it running. The two systems are totally different, the waterlines are under pressure; the drain lines run by gravity and have vents to avoid pressure buildup. If the problem continues have the landlord get somebody to look at it.

Answer 2

A drain pipe cannot flow into a water line within the home, apt. its'self-- a "water line" comes from the source, well or city water it is a closed system besides it source. Unless someone purposely did this. Your well could be polluted or the city sewer ran into the city water but before it got to your home.

Answer 3

They should be separate. The drain system does have to have a vent pipe that usually goes up thru the roof. It uses gravity flow so it needs an airway above it. I haven't heard of a water line that would be connected to it tho', since that system needs to be pressurized.

Contact the building super ASAP.

Answer 4

I can give a possible case were it may if a handheld shower wand is left in standing water in the shower booth. Could the hose drain and refill with dirty water? How about the siphon affect?

Answer 5

This is not possible, these are apples and oranges, two different lines completely separate. Either what you saw was something else or this is a coincidence.
Your lines cannot "back up" this way, there's no means of a conduit for them to be connected.

Answer 6

That's bad. Tell your landlord to get a plumber for poison in the lines or call the health dept.

Answer 7

It is not possible. If you think it is, you're a moron.