Wireless Water Sensors

I installed my Elk M1G over ten years ago and it's still working flawlessly. I installed some CADDX GE wireless PIR sensors and that too has been working well. Yesterday my coworker's house flooded when a flexible hose going to the toilet broke, and I want to make sure that doesn't happen to me. So I figured I will will need an electric water shutoff valve to secure the water to the house, and I will need about ten water sensors. For sure I will want a wireless system. And then I found out Elk really isn't working with GE/CADDX any more and I should maybe consider going with the new(er) Elk wireless receiver. I'd love to keep the receivers in the $20 range or less, if possible.
 
Thoughts?
 
Should I find transmitters that work with my CADDX or should I upgrade everything to the new El wireless system?

Which wireless receiver do you have on your Elk now?  The M1XRF2G or the M1XRFEG?
 
I believe the Interlogix TX-E611 will work with the M1XRFEG.  Not sure if it will work with the older 2G.
 
If you have the M1XRF2G, the Interlogix NX695 (aka 60-744-95RA) should work with that, as well as the M1XRFEG. 

I don't have an actual Elk receiver at all. I don't know what it is since I got it ten+ years ago. I've attached a picture of it here.
 

Here's a link to higher res photos
https://photos.app.goo.gl/9mQjK9ckduH2pchJ7
https://photos.app.goo.gl/b83HZhfT4TfzoFn18

Ok, now I understand your situation better.
 
Your photo looks like a Caddx NX-548E receiver, or maybe one of the other NX series receivers.   The NX-548E is compatible with the Interlogix NX-695 water sensor I mentioned above.
 
The Caddx receiver is no longer supported by the newer firmware levels on the M1.  But if your system is stable and running well, I don't see a need to upgrade just for the sake of upgrading.
 
The Elk Two-Way Wireless receiver (M1XRFTW) doesn't yet offer a wireless water sensor.  So if you decided to get rid of the Caddx receiver, then your choice would be to go with the M1XRFEG or the Honeywell-compatible M1XRF2H.   The advantage of the M1XRFEG would be that it should be compatible with all of your existing wireless sensors.