"Don Phillipson" wrote in message
...

Check for a subsurface cause, e.g. plugged tile bed or broken sewer or
main water supply line.

Now that's food for thought. We live on a small lake (aprox 8 or 10 acres)
and about 4 or 5 ft from the effected area is an under ground 18 inch street
drain pipe that runs from the street back along our property line to the
lake which is probably 20 ft from the effected area. The line stays dry
except when it rains.
I see raccoons go into that street drain every now and then, wonder if maybe
they could have a den in there that's causing the problem? They could go to
the lake end of the pipe, catch a fish and take it back to the den and cause
organic waste.

Thanks for the tip, RM~