What stinks?

January 12, 2006 12:55 PM

How do I get rid of that faint smell of sewage in my basement?

I have an indoor sump basin in the basement that stinks. It's used only to collect water from a sink, which is then pumped into my sewage line. It is properly plumbed (with a trap). I think the smell comes from the waste water from the sink, just sitting in this basin until it reaches a level where it is automatically flushed. (Explanation: the sink is below the level of the sewage pipes; therefore the water must be pumped out of the basin.) Part of the problem may be that, because I don't use the sink very often, the waste water may sit in this basin for weeks before it is pumped out.
Is there something I can add to the basin to cut down the smell? Is this simply a job for bleach?

posted by sixpack to Home & Garden (5 answers total)

I'm thinking what you should have is an in-the-drain-under-the-sink pump, that just pumps the water up directly into the sewage line. That way it functions just like a normal sink, rather than this open basin arrangement. If you're getting a sewer smell, you've got an open connection someplace (and sewer gas could explode, by the way -- this has been known to completely level a house). How does the sump pump connect with the sewer -- is there another trap at that point?
posted by beagle at 1:19 PM on January 12, 2006

Response by poster: I would describe it more as an under-the-sink sump pump. The basin is completely closed, except for an inlet for the pipe from the sink. Then two outlets, one for the water (to the sewage lines) and one for a vent, which is vented to the outside.

There is no trap between the pump and the sewer. The trap is between the sink and the basin (as per the installation instructions).
posted by sixpack at 1:29 PM on January 12, 2006

That stuff sounds good, and to get rid of the residual smell, baking soda in several open containers around the basement and a dehumidifier (if you don't already have one).
posted by Doohickie at 5:40 PM on January 12, 2006

Perhaps you could set the float level in the pump to turn on at a lower level of water?

I was going to recommend adding bacteria to the pump, but then I googled it, and found out that won't do much (if anything). source 1 source 2

I'm building a new house, and we just got water running on Monday. Our basement setup is identical to yours (albeit with a full bathroom going into the sump pump). I'll be curious to see what other suggestions people have.

Oh. There's always paperwhites.

I do think setting the float level lower might help.
posted by Alt F4 at 5:51 PM on January 12, 2006

Best answer: Assuming there are no leaks, the only way for the smell to get out is via the trap under the sink. Just pour in a few litres of water to make sure the trap is full and doesn't have stale stuff in it. If you haven't used the sink in weeks, the trap may have dried out and you're smelling the basin contents.
posted by polyglot at 6:15 PM on January 12, 2006