Once the oil smell fades, there is no detectable odor.

Also, many of the real estate websites have bot detection, so your programmer might need to get creative.Joe

Not a great return but if we did it, it would have been an interesting experience and we could have spent some down time away from the reno out in the W.A gold feilds camping exploring and metal detecting.

She mentioned that she found a camera that would allow you to insert a sim card in it and it would work with motion sensors and only uploaded images when motion was detected through the cellular data plan of the sim card.

The plumber I used had a listening device that can detect leaks when everything is shut off.

I have found a couple of devices which seem to do the job:https://www.amazon.com/bluebot-Universal-Detection-Tracking-Required/dp/B08V9DKFR3/ref=psdc_3180231_t1_B08DX6MP8X https://www.amazon.com/Moen-900-001-4-Inch-Smart-Shutoff/dp/B00C03D01QInstalling multiple meters is a non-starter due to the price. 

Static testing can find what are called "high leaks" in your lines and is the only way to detect most leaks in sub slab plumbing. 

When she took a shower the sensor did not detect movement so it turned off after 5 minutes in the shower. 

By the time somebody detected the problem the water pipes had burst, ceilings had dropped and lots of damage to the house and furniture, to the tune of $46,000.We had an incident where the gas company turned the gas off, by mistake, wrong address, in a vacant house and we had over $50,000 in damage. 

Account Closed I don't use  monitoring although I know some landlords have used tray with the leak detection alarms with some luck.