If you have a zigbee network the aqara leak detector is a good option. It doesn't require a hub, cloud or any setup. And if you are willing to wait you can get them on AliExpress for a lot cheaper than Amazon.
I have a few of the Aqara leak detectors and they have worked well.
They also have screw terminals that you can attach wires onto to extend the detection area/range. I’ve also seen people attach contact or pressure sensors to them, they are nifty devices.