You may remember the Household AC Power Monitoring System using Clamp Meters  that Jason Winter made which was featured earlier this year. Web Monitoring of Water Usage using an ioBridge is his latest project. As you can see from the pictures he lives in a climate where water pipes don’t freeze. Up here in Canada we are not so lucky. If you prefer the instructions in an Instructables format it is located here.

"The water meter comes with a 6 ft section of cable. My ioBridge module was in my house above. I drilled a tiny hole in the floor and ran a long section on 2-conductor wire from my ioBridge module, through the hole in the floor, to the water meter. I just soldered the wires, covered them with heat-shrink tubing and tucked the wires behind the water line to keep them from getting exposed to the elements. I just connected one wire to ground and the other to a digital input. The water meter contains a reed relay contact switch. As the meter reads each gallon of water, it connects and disconnects the switch. All ioBridge needs to do is read the numbers of times the switch closes to get the number of gallons used. The latest revision ioBridge modules have built in pull-up resistors, so I didn’t even need to add them myself "