Nitin,
Your design concept is dreadful. You are relying on the conductivity of the water, the input impedance and noise margins of the processor, the ability to ignore electrolysis etc. And no, your relay scheme still leaves net DC on the pins.

Where I live the conductivity of the water from the tap is <<1 micro Siemen and there wouldn't be a chance in hell of getting it to work.

MUCH better is a capacitance schemem which can be driven by the micro and sensed by it too.

Steve