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I give the Shelly Flood Gen4 4.5/5. It’s been solid for my basement setup. I use it to watch for spills from the A/C condensate line, which has been knocked out of its drain a few times, and from the washing machine’s drain hose if it comes out of the sink.
My complaint is that I’d like to adjust detection sensitivity. I couldn’t find a sensitivity setting in Shelly’s documented controls. There are alarm-mode settings and a configurable delay before reporting a sustained wet state, but those don’t adjust the detection threshold. Otherwise, I’m happy with it.
The Flood Gen4 is unusually flexible: one leak sensor that can run on WiFi, Zigbee or Matter depending on your setup, all locally in Home Assistant with no cloud. The included leak cable detects water along its length, which beats a single contact point. A strong, affordable pick for leak protection on a local-first network.
Standout: Multi-protocol leak sensor (WiFi, Bluetooth, Zigbee, Matter) with an extendable leak detection cable, fully local.
Notes last checked May 25, 2026.
Gen4 sensor supporting WiFi, Bluetooth, Zigbee and Matter. Works locally through the native Home Assistant Shelly integration or via Matter, with no Shelly Cloud account required.
Home Assistant support: supported · integration path: Shelly (native / local) or Matter.
Price notes: Around $40 at Amazon (verified 2026-09-03); it had been running in the low thirties. Includes a leak sensor cable in the box.
Verified price reads: lowest seen $39.99, latest $39.99 on Sep 10, 2026.
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The compatibility notes above have not been through the source audit yet. The manufacturer's page is here; the notes were last checked May 25, 2026.
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