Today we noticed the drain our washer empties into was backing up. My husband poured drain cleaning into it but it did not help much, after about 8 hours he repeated the same procedure, shortly after I notice a fowl smell like rotten eggs emitting throughout my house is this cause for concern?

Not if you like that small... :)

But serious : drop caustic soda crystals in that drain pipe. Follow up with hot water. Be careful for the chemical reaction afterwards, that may produce foaming and splattering.

Success !

:)

today we noticed the drain our washer empties into was backing up. My husband poured drain cleaning into it but it did not help much, after about 8 hours he repeated the same procedure, shortly after I notice a fowl smell like rotten eggs emiting throughout my house is this cause for concern?
What you smell are the chemicals working away in your pipes and allowing the smell to exit out the washer standpipe. If the blockage persists you may have to snake the drain from the washer roof vent **or** you could snake from the stand pipe if you wish. Good luck, Tom