Thanks for the insight.
My question was not specific enough.
I am looking for an electronic leak detector that will alert renter if the toilet is leaking via an audible tone, similar to a smoke detector.
Yes we can discover leaks on inspection, but we are looking for an early warning device that senses water wastage when it happens instead of upon inspection.
This not only lets the resident know that there is a leak; it also stops the leak.
The resident will know when he/she tries to flush because the toilet will not flush (your maintenance dept will get a call).
The electronic device that you mentioned sounds like what is used to detect water that has made it onto the floor (such as from a water heater leaking). I think the Fluidmaster will serve your purpose much better at less than 1/2 the cost.
Your product suggestion is very interesting and might be what we are looking for.
We do use the leak detectors that sense spilled water, but this may solve the internal water wastage problem. But our maintenance guys might be less than pleased when one of these locks up and they have to endure the "leftovers!" Oh so is life, better than pouring $ down the drain.
Again thank you very much for your time in assisting.