sensor

Shelly Flood Gen4

budget Owned and reviewed local: excellent Wi-FiBluetoothZigbeeMatter

Price: $39.99 verified Oct 31, 2026
HA fit: excellent
Offline: yes
Setup: easy
Hub needed: no

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Shelly Flood Gen4, a battery-powered water leak sensor puck for laying on the floor

Owner’s hands-on review 4.5/5

Solid leak monitoring; I wish sensitivity were adjustable

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.

OneDroidyHome · 2026-09-13

Quick verdict

The Flood Gen4 is unusually flexible: one leak sensor that can run on Wi-Fi, 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 (Wi-Fi, Bluetooth, Zigbee, Matter) with an extendable leak detection cable, fully local.

Notes last checked May 25, 2026.

Compatibility snapshot

Home Assistant excellent

Apple Home good

Google Home good

Alexa good

Works offline yes

Setup easy

Extra hub needed no

Power battery

Local control facts

Home Assistant: shelly integration, Local Push, Platinum on the quality scale (home-assistant.io, checked Oct 10, 2026)
Zigbee2MQTT: supported device, listed as Shelly S4SN-0071A (Flood Gen 4) (zigbee2mqtt.io, checked Oct 10, 2026)

Why it stands out

flexible protocols: Wi-Fi, Bluetooth, Zigbee and Matter on one device
includes a leak sensor cable that detects water along its full length, not just one point
fully local through the native Shelly integration or Matter, no cloud needed

Reasons to hesitate

battery powered, so it reports on intervals rather than instantly when idle
you must pick one radio mode per device, configured at setup
Matter water leak support in Home Assistant is newer than Wi-Fi Shelly support

Best for

protecting water heaters, washing machines and under-sink areas with local leak alerts
Home Assistant users who want a leak sensor that fits Wi-Fi, Zigbee or Matter setups

Avoid if

you need a hardwired, always-on sensor with instant reporting
you want a purely Zigbee-mesh sensor and do not want to manage Wi-Fi or Matter pairing

Privacy and local-control notes

Gen4 sensor supporting Wi-Fi, 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.

Buying reality check

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 $31.99, latest $39.99 on Oct 31, 2026.

Oct 31, 2026$39.99amazon
Oct 24, 2026$39.99amazon
Oct 17, 2026$39.99amazon
Oct 10, 2026$39.99amazon
Oct 8, 2026$31.99amazon
Oct 7, 2026$31.99amazon
Oct 6, 2026$31.99amazon
Oct 5, 2026$39.99amazon

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What changed for this product

Oct 10, 2026 · Brief

Black Friday smart home deals for Home Assistant: the prices to beat

Black Friday 2026 smart home deals for Home Assistant and local-control homes: the lowest price I've recorded for 100+ Zigbee, Z-Wave, Matter and Wi-Fi devices.
Sep 24, 2026 · Brief

Schneider Electric is buying Shelly: what it means for local control

Schneider Electric agreed on September 24, 2026 to bid EUR 70 a share for Shelly. What the deal promises, and whether to keep buying Shelly gear.

From the change log and the news briefs that name this product.

Verified against

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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