Newbie questions re: 433MHz water sensors

I’m wanting to be able to sprinkle a bunch of cheap water leak detectors around my house, and have them automatically turn off my water main in the event any of them get wet. I’m open to any “kind” of sensor, but I’d like them to be as cheap as possible, battery operated with a long battery life, and ideally be able to monitor battery level in each sensor.

Z-wave sensors are quite expensive and the battery life is not great…zigbee seems to be a little cheaper and battery life a little better, but I haven’t found anything that seems great. WiFi sensors seem about the same, but with the added uncertainty of “can this actually integrate with HA?”…it’s too bad wyze doesn’t make a water sensor…and then there’s the 433MHz sensors like this which look promising. They’re the form-factor I’m looking for…and I think the battery life seems better on them? (Altho I couldn’t find any battery life info on that one specifically). The info on how to set these up is really spotty tho…does anyone know how they work? Am I right in assuming I’d need a receiver like this, and run something like this and then somehow bridge that to mqtt (what is mqtt anyways?) which would get it into HA? How do these types of sensors authenticate/pair with the controller? (Or do they?)…I have an existing sensor as part of my home alarm system that I assume is also a 433MHz sensor, could I also receive the signal from that one? Do these sensors report battery level? I’m guessing they don’t…

You can find 2 water sensors in the list below:

I haven’t tested the power consumption of this one but I have done it with the second one, more details below:

You’re on the right track, yes to the sdr dongle, yes to the rtl_433 and yes to mqtt. I use this set up for a number of weather sensor around my house.