I am working on a project where I need to detect if there is a leak coming from a tank, boiler, etc. In principle, if I have understood this correctly, these types of probes function as a simple resistor-type circuit, where if the two electrodes of the sensor short or show a drop in resistance, this would indicate the presence of some form of liquid or water.

Is there anything additional we should keep in mind, especially if there will be multiple probes in the system?

Are there any reliable manufacturers who make such probes that I could use?

 

Probably not the answer you're looking for but I just ordered one of these to catch when my humidifier leaks.
https://www.amazon.com/dp/B0748RK2XQ
I chose it over many others because it does not require a hub. It's wifi and stand-alone.

And yes, I think most of these devices measure conductivity between two small probes that you set up to touch your floor. If they get wet, current flows and triggers the alarm. It's conceivable a distilled water spill might not trigger? I guess even distilled water is more conductive than air.