electronic water flow rate measurement

If I ever have time I can put one of these together with a circuitboard thattransmits to wifi so you can get an email alert for continuous running. IE a leak.

https://www.sparkfun.com/products/11183



and a shut off to shut it off at a certain time. say running for an hour.
https://www.sparkfun.com/products/10456





$10.00 one not for precise measurement, but can be used to tell if water running for extended periods.
http://www.adafruit.com/products/828


http://www.adafruit.com/products/833



http://www.adafruit.com/products/996


expensive but mechanical motorized
http://www.hometech.com/hts/products/security/floodstop/el-wsv.html?key=A27&pk_kwd=EL-WSV

reasonably priced
http://www.homesecuritystore.com/p-1091-fs-34-h-flood-stop-system-for-washing-machines.aspx?affiliateid=10050&wm_ctID=359&wm_kwID=21942114&wm_mtID=1&wm_DefaultURL=http%3A%2F%2Fwww.homesecuritystore.com%2F&source=origin