I have a drain on the floor next to my washing machine. What is the purpose of this drain? I assume to handle any water if the machine overflows? I ask because last week it was giving off a bad smell. By suggestion of someone who knows a little about plumbing, I poured some fresh water down there and the smell went away. The water flowed freely, so I guess there's no blockage. When I look down this pipe, I can see water sitting there. Is there supposed to be water sitting in there? Again the fresh water was forcibly poured down with no problem. I think it's starting to give off a little smell again. I don't know if I need to call a plumber or not. Thanks for any info you can give me.