A cross connection happens when a sump pump is connected to a sanitary sewer line.  Often, this can be a hose leading into a laundry tub or a floor drain.  Sump pumps are supposed to drain into storm sewers, either through a direct connection (a pipe from the home connecting with the main storm sewer line), or by draining directly onto the ground through a pipe or hose outside the home.

Sump pump water is what engineers refer to as clear water, most often rainwater, ground water, or snow melt.  This water is clean enough to drain directly into area streams, ponds, and lakes without treatment.  Wastewater, water from your sinks, showers, tubs, toilets, and washing machines, must be treated at your area wastewater treatment plant before it can be safely discharged into the environment.

When clear water is added to wastewater, it can overload the collection system.  The Minnesota Pollution Control Agency (MPCA) has estimated that a single home with a cross connected sump pump can add up to 1,400 gallons of water to the system during one average rain storm.  That's the equivalent of flushing your toilet 280 times based on a standard toilet with a five-gallon tank. Multiply that by the number of homes in your neighborhood and the magnitude of the problem becomes evident.

Excess water in the treatment system costs the City and you  Rates at the treatment plant are based on the number of gallons that flow through the system.  When clear water enters the system through cross-connected sump pumps, everyone pays to treat water that is already clean. 

No.  The other source is ground water that can also infiltrate the sewage collection system through bad joints, cracks, or breaks in the sanitary sewer pipe.  The City regularly inspects the interior of the sanitary sewer pipe so problems can be found and corrected.

The key to look for is where the water goes when the sump pump is pumping.  If you have a pipe that goes outdoors, and drains into your yard (well away from your foundation), your sump pump is not cross-connected.  If you have a hose that drains into your laundry tub or floor drain, your sump pump is cross-connected.  If you can see right away that your sump pump is cross-connected, it would be to your advantage to get it re-routed prior to inspection.  This will save you time, as only one inspection will be required to confirm a correct connection.  If you can't tell, don't worry, the inspectors will let you know and you will have time to get the problem corrected before the non-refundable fee is applied.