It sounds as though the municipal sewer has insufficient capacity for the amount of water it is expected to carry. Has anyone spoken with the local public works department.

Short of that you need a backflow check valve to prevent back-up and/or a lift station with pumps to force your water into the sewer while also preventing backflow. There are several brands available, Tramco is one with which I am familiar and know to be good.

Hope this helps.

Thank you for your quick response!

This is NYC. I don't think speaking with the local public works department will help in the short term (nor probably in the medium or long term). ;-)

A check valve would prevent the sewer from backing up into the basement, but that would also prevent the roof runoff from exiting through the sewer pipe, wouldn't it? Not that anything is exiting through the sewer pipe anyway, since that pipe is streaming into us!

Is there anyway to make the sewer pipe "one-way"? Or is that what the lift station with pumps is about? (How many pumps? Are they the same as a sump pump?)

Any idea how much it would cost to buy and install such a thing?

Sorry for all the dumb questions! I'm just starting to learn about all this stuff!

Thanks!

You would need to have a qualified local expert evaluate your situation. About 20 years ago I had a Tramco liftstation unit installed but it involved some extensive upgrading of electrical power and required a new driveway due to the excavation.

Mine handled the entire house - sewage and rainwater because the community had combined sanitary and flood-water sewers. It intercepted the main line leaving the house. The total then was around $10,000, as I recall, but the unit I selected had two pumps which alternated because I did not want to risk a pump failure when I most needed it. I even had mine wired to be connected with a generator though that never became necessary. I don't recall how large the pumps were but, yes, a form of sump pump but ones having sufficient output pressure to pump against any back-up.

Aside from annual preventative maintenance the problem was solved. I lived there about 5 years following the installation and never had a drop of water in the basement again.

Good luck resolving your problem.

Following in a link to the Tramco Lift Station I reference. Seeing this, I recall mine being a model 990 as I know it had two pumps.

This is top-end equipment - I'm sure other solutions are available to meet your specific requirements.

I bought through a local installer that my village recommended so have had no dealing directly with the manufacturer.

Having experienced water in a basement I know the trama and hope this provides you a place to begin.

Here is a link that might be useful: Tramco Lift Station

Thanks! This is great information. :-)

Proving once again that combination sewers were and are a terrible idea!

Perhaps there is a dedicated storm sewer system that can be accessed. Or perhaps there's a way to divert some of the rain water to on-site drainage. That would depend on how large the building and/or lot are.

It's an 80-unit building (8 floors). Not much ground around it.