Had an interesting thing happen recently. I noticed a while back that flume was registering almost zero water flow daily - like .1 or .3 gallons a day. obviously we are using more than that. I assumed the batteries were dead/dying, but when I checked the app it showed them at 100%. That really didn't make sense as I've had the sensor in place since Feb of '22, a few weeks past two years ago!
Yesterday I finally made time to look into it. Went out to the water meter out front and found (as sort of expected) a mess inside there. It's one of those underground w/a concrete lid over it. There were bugs, black widow spiders, dirt, dust and debris, likely due to significant storms we've had over the last few months. The Flume sensor was still in place w/its strap around the meter, but dirt and debris had worked it's way between the Flume sensor and the meter.
I cleaned things up a little w/out actually removing the sensor. (Admittedly a little freaked out by the black widows.) I moved the meter back and forth and disloged/removed as much as the dirt/debris between the sensor and the meter as I could. Ran some water and checked the app and water use was registering normally again, and appears to be working normally now.
One surpise is that the sensor is still reporting full battery to the Flume app, which it obviously can't be after two years. I'm thinking that it may update at some point, but it's been over 18 hours since I cleaned/adjusted the sensor and still showing 100%. Regardless of what it's reporting, I am mightily impressed that it still has enough juice to run at all after just over two years. IIRC I haver the black shrink-wrapped version of the battery pack.
I have a buried power line nearby, so at some point I'd like to follow through on plans to setup a wired power connection for the sensor, but there always seem to be too many honey-do's that I am told have a higher priority. 
This small adventure reminds me to thank you again, @tomw for the integration. 
