My house was built in 1937. There's a basement drain near one corner that has never flooded. I have a dehumidifier parked over the top of it that drains into it (and has done so for about 10 years; I've also drained hot water tank and boiler into it as needed, so it works).

The last two heavy rains, my basement has flooded with about 2 inches of water. The water is clear, relatively clean and cold (it's about 40 degress outside). So it seems to me, it's tied into the storm sewer, rather than the sanitary sewer then?

I also have about half of the downspouts tied into pipes that are mortared shut -- the others drain around the foundation (they had already been removed or there were no pipes there). One of these pipes was clogged, so I disconnected the downspout after the first flood. The second time around, I seemed to get about half as much water.

My question is, do you think I have a clog (or partial one) somewhere in my drain tile and that the heavy rain from my own house is then backing up into the basement? Or is the city system backing up and causing my problem? I've never had any problems like this in the 10 years prior, just a little wall seepage during the rainy months, nothing major.

Also, is there something I can do to the basement drain (backflow valve?) to prevent this? I like having the drain, because then I don't have to empty the dehumidifier. But I also don't like getting 2 inches of water in my basement every time we get heavy rains.

Thanks!!

It sounds more like the storm sewer's connected to the sewer line going to the street. You may have a partial blockage that allows the normal passage of liquid but can't handle the influx of a heavy downpour. It's illegal in my area to tie roof drains, AC condensate lines or water softener discharge into house sewer lines. Try snaking out the line from the house clean out to the street and see if the problem doesn't go away. Good luck, Tom

It sounds more like the storm sewer's connected to the sewer line going to the street. You may have a partial blockage that allows the normal passage of liquid but can't handle the influx of a heavy downpour. It's illegal in my area to tie roof drains, AC condensate lines or water softener discharge into house sewer lines. Try snaking out the line from the house clean out to the street and see if the problem doesn't go away. good luck, Tom

But when the basement drain is overflowing, you can still flush the toilets and such with no problem -- though I guess what you could be saying is that the clog may be before the tie-in to the sewer?

Couldn't I also just disconnect the remaining downspouts from the system? Then there wouldn't be any rainwater even going to the clog. The dehumidifier doesn't put out much water and that drain is not really used for anything else (in 10 years drained the boiler into it once and the hot water tank once).

I also saw your post to another using regarding a flood guard drain protector. I think I'll get one of those too so I don't have to worry about it. Thoughts?

Thanks.
Todd