There are 2 drains in my basement. There has been significant rain here the past 2 weekends. The drains backed up each time flooding the whole basement floor and are very slow to drain out. I have always had some water leakage from basement perimeter after heavy rains, but not to this extent.
I recently had a functioning half bath installed on the second floor directly above the main floor bathroom. This is the first significant rainfall since that installation.
My questions: Could this installation have affected the drainage in any way? What measures do I need to take?
Thanks so much.

If these are basement floor drains (the ones that are backing up) that are connected to your home sewer line then I'd have the line cleaned completely to the street. There may be grass or tree roots that have made their way into the sewer line, or it may have a partial blockage from something else. Some drain cleaning companies can put a camera down into the line to inspect it, see if the sewer pipe has partly collapsed in places, this sometimes happens especially on older homes. You may have had a slowly developing problem with the sewer drain line, adding the additional bathroom shouldn't be the cause of a problem unless you have increased the number of people in the home and have more stuff going down the sewer line.

The ground water from rain shouldn't be causing a blockage with your floor drains. Not sure why rainfall would cause a basement floor drain to backup, the sewer drain pipe is sealed from house to the street sewer connection, so no ground water should be getting into it. Do you also have a sump hole/well in the basement somewhere, with a sump pump to remove rain water that comes in around the basement foundation?

Are your basement floor drains maybe not connected to the house sewer line, but instead are connected to a separate drain pipe that runs outside onto your property and drains out there somewhere?



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I always hate when that happens. How old is your house/drainlines? Depending on age, use and abuse... your sewerline needs some attention. It needs to be cleared and cleaned. A camera inspection can determine if your line is defective, allowing roots to invade your line, thus creating slow draining or blockages.

Ask your neighbors if they have issues. If so, its possible that the street main has issues. You might wish to consider installing a backwater valve to protect your basement again backflow during the rainy seasons.

Best Wishes

if while the basement was flooded but draining out slowly, you used your upstairs bathroom and go no evidence of toilet paper or soap bubbles showing up in the basement, then the 2 are unrelated..