hey .can we use it for measuring water level in a underground tank.

How can I get a copy of the schematic ? Will be very much appreciated.

Hey,
This module measures pressure and temperature, rather than any distance information. I would suggest you use an ultrasonic range sensor which can give you the exact distance from the sensor to the top of the water level https://www.dfrobot.com/pro... or another sensor of ours can detect a water level at a preset height and trigger when water is present:https://www.dfrobot.com/pro...