After plunging sink basin drain, supply water is brown

[hbrizzims]

Yesterday my bathroom sink was draining slowly. I checked the stopper and the trap, then plunged with the vent blocked. This made the clog hold better and slow drain became a complete blockage. More plunging to no avail. I then went to check other drains to see how far down the clog was, and the supply water in the shower, toilet, and kitchen sink came out brown/yellow.

I don't have a dishwasher, but do have a washing machine hooked up and a dryer (with steam function) hooked up to supply lines. Galvanized iron pipes in this house too. (I rent, otherwise would replace) We're the ground floor of a two story duplex.

Any idea how the plunging affects the supply line? Is this indicative of a bad situation in general? Sink works fine, plumber came by while I was at work and snaked the drain.

 

[desertwater]

The brown/yellow water is most likely from the galvanized system and has nothing to do with the slow drain or any drain. knowing you have galvanized plumbing its most likely above slab and if you had some kind of siphoning going on you would know about it. its time for a repipe!