Water level system in my PC (parallel port)

Hi,

I am interested in control a water pump system (relay controlled by parallel port – no difficult) but, to make decisions, I also wish read various water levels points (water sensors) in parallel port input of my PC.

My problem is only a hardware problem (I am not an electronic expert) - Sensor and Interface PC-Sensors.
I work with LabView to program parallel port.

Thanks in advance for any help you may provide!