sump pump discharge into drain line

[AHI in AR]

I found a sump pump discharging into the drain under the kitchen sink overhead. I'm not sure if you should do this at all, but if it's allowed shouldn't there at least be a check valve installed? True basements are extremely rare around here so I've never seen anyone do this before. Typically any sump pump I see in a crawlspace is piped separately so it discharges on the ground outside.

So is this method Kosher or not?

[kurt]

Nope. Needs a check valve, and I'm not aware of any area that wants groundwater discharge into a sanitary system.

[kieferma]

Agreed. Do not want groundwater discharging to sanitary system.

[John Kogel]

Could it have been an effluent pump for basement plumbing? I say this because you admit to not seeing a lot of basements.

Google 'sewage ejector pump'.

[Erby]

The city of Lexington, KY dislikes sump pumps adding extra, unneeded water to the sanitary sewer system so much that it offers to pay the cost of redirecting the sump pump discharge.

http://www.lexingtonky.gov/index.aspx?page=2392

Adds millions of gallons of water that don't need treatment to an already overloaded treatment system.

I've heard several other cities are trying the same thing to reduce the cost of their sewer treatment.

[AHI in AR]

Thanks for the replies. John, it's definitely not an ejector pump. While not common, I have seen those previously in daylight basements. This is just a garden variety open sump.