Sensing water?

I have a project that I'd like to do which would basically just alert me if water is detected. We have a basement location and with some storms, water creeps in when no there, which is a bad thing. I've searched this forum as well as the internet without much luck on what type of sensor would be used for something like this. Something I could run the wire next to the door, and just stick it in a corner location, so when water came in, it would immediately detect the moisture.

Electronics newbie here so forgive me if this is a super simple question. One thing to note there are small children in the area so I'd like to have something that's clean and protected.

Thanks!

water will conduct electricity so putting two nails in the place you want to measure 1 cm apart, connect one to 5V and the other to an analog input.
connect the analog port with a resistor to GND too and you have a minimal system to check for water.

Similar recent discussion here:
http://arduino.cc/forum/index.php/topic,152516.0.html

I would use this sensor…

http://www.robotshop.com/productinfo.aspx?pc=RB-See-186&lang=en-US

http://www.robotshop.com/content/PDF/grove-moisture-sensor-sen92355p.pdf

Perfect, thanks everyone! I think I'll give the sensor listed a try.

I appreciate the help!

You could use just two wires as a conductivity tool. One would be VCC+ and the other one would be connected to a pin that would sense the voltage fro the VCC+ with the analogRead() function. When the two wires contact the water the flow of electricity become higher and that way you could detect if there is any water.