I'm a little confused, you say when you water the lawn close to the house, the water runs off through the tiles?
If this is so, that would mean the water from the hose is going down under the footings and back up to the tiles to run into the sump hole?
Either I am not understanding this midwest construction, or something is just plain wrong!
You say the house is forty years old. Are there any other homes near you and do they have the same problem?
Are there records of how the house was built in your local town hall.
Is your house built on a spring? I once went in a house that had a running 6" wide spring that came in through the front stone foundation and ran out the back!
As a general rule, You should be able to control the moisture in the basement. If the cement blocks were sealed properly, If you have a perimeter drain and if you use a dehumidifier low to the floor, and with the drain set to go into the sump hole.