I just had a flood in my basement after a very heavy rainfall. The water is coming in where my sewer line comes in the house. The water is clean rainwater the plumber told me and is seeping in through the cement, I can see it bubbling up through the cement in the hole where two 2 sewer trap caps are. The plumber opened one of the caps and the water went all the way down. He told me to buy a cap that can seal the sewer and also can let water drain if it comes in again. He said it is some special cap that won't let the sewer water come in, in case of a backup but will let excess water drain through it. Has anyone ever heard of a cap like this and if so where do I get one?

He could be referring to a back water valve? It's a one way valve that allows water and sewage to travel out, but not back in. They are usuall installed inline on the sewer line. Where I come from they are code on new construction but didn't used to be, so lot of old houses have issues like you described.

EDIT - if this is indeed what you are after, I have seen them at major reno stores, but I just read your post again, and what I'm thinking is an inline valve, usually installed on the sewer line, under the slab. You would probably want a pro to install. I'm not familiar with one that works as a "cap" on the end of the floor drain. But that doesn't mean they don't exist.

Hi Mike

I'm not sure about a "CAP", but sureseal makes a floor drain seal that can be adapted to this application pretty easily... check out the link at this page:

Home: SureSeal Waterless Floor Drain Trap Sealer (http://www.thesureseal.com/)

You can also check out this video... may give you an idea or two:

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You may need to purchase a threaded reducing adapter (install in plug threads) and then install the sure seal, but it would work for you!

You could also call the plumber and see exactly what it was he was referring too.

You may also want to consider installing a sump pump as back up here??

Back to you...

Mark

Ya, where I'm from sump pits with pumps and back flow valves are code now, to hopefully prevent any flooding. Rain water is always better than sewage in my opinion I guess if something is going to flood.