Smart water leak sensor Shelly Flood S Gen4 - CR123A battery powered, built-in buzzer, Flood and Rain modes, Wi-Fi, Bluetooth and Zigbee, Matter, app control, compatible with Home Assistant
Description
Shelly Flood S Gen4 is a compact, battery-powered flood sensor designed to detect leaks early and prevent costly damage. The contacts are made of large stainless steel plates, for fast and reliable detection even with clean or low-conductivity water.
The low-profile housing allows mounting exactly where leaks occur: under appliances, next to the plumbing or in hard-to-reach corners. The sensor has two operating modes, Flood and Rain, and three alarm profiles (Intense, Normal and Economic), which can be chosen depending on the space, plus a built-in buzzer for local warning. It communicates via Wi-Fi 6, Bluetooth 5 LE and Zigbee 3.0 and supports Matter over Wi-Fi, integrating with Shelly Cloud, Home Assistant and other common platforms.
Key features
- Detection via large stainless steel plates, effective even with low-conductivity water
- Flood and Rain operating modes
- Three alarm profiles: Intense, Normal and Economic, with different reporting frequency and buzzer behaviour
- Built-in buzzer for local alarm, independent of the network
- Powered by one included CR123A battery, with an estimated battery life of about 2 years
- Wi-Fi 6, Bluetooth 5 LE and Zigbee 3.0, with Matter over Wi-Fi support
- Low-profile housing, for mounting under appliances and in tight spaces
- Integration with Shelly Cloud, Home Assistant and other automation platforms
Practical use cases
- Under the washing machine in the kitchen. The Normal profile triggers the buzzer and sends an app notification at the first contact with water, and through a local action it can close a Shelly smart valve before the water reaches the wooden floor.
- Technical room or server room. The Intense profile reports the status every 30 seconds during the first 5 minutes and keeps the buzzer active, suitable where an unnoticed leak means major damage to equipment.
- Rarely visited vacation home. The Economic profile disables the buzzer and reduces reporting to save the battery, but keeps the app alert active for the whole time the home stays empty.
- Terrace or motorized awning. In Rain mode, the sensor detects precipitation and can automatically trigger retraction of the awning or stop the irrigation system.
Technical specifications
| Construction and dimensions | |
| Dimensions (H x D) | 23x77 mm / 0.91x3.03 inch |
| Weight | 50 g / 1.76 oz (without battery) 70 g / 2.47 oz (with battery) |
| Mounting | Flat surface |
| Housing material | Plastic |
| Housing colour | White |
| Environmental conditions | |
| Ambient operating temperature | -20°C ... 40°C / -5°F ... 105°F |
| Humidity | 30% ... 100% RH |
| Maximum altitude | 2000 m / 6562 ft |
| Electrical parameters | |
| Power supply | Battery |
| Battery type | 1 x CR123A (included) |
| Estimated battery life | approx. 2 years (depending on the battery used, usage and signal quality) |
| Sensors and metering | |
| Water detection | Da |
| Radio communication | |
| Wi-Fi | |
| Protocol | 802.11 b/g/n/ax |
| RF band | 2401 - 2483 MHz |
| Maximum RF power | < 20 dBm |
| Range | up to 30 m / 100 ft indoors and 50 m / 160 ft outdoors (depending on local conditions) |
| Bluetooth | |
| Protocol | 5 (LE) |
| RF band | 2402 - 2480 MHz |
| Maximum RF power | < 20 dBm |
| Range | up to 10 m / 33 ft indoors and 30 m / 100 ft outdoors (depending on local conditions) |
| Zigbee | |
| Protocols | 802.15.4 |
| RF bands | 2405 ... 2480 MHz |
| Maximum RF power | < 20 dBm |
| Range | up to 100 m / 328 ft indoors and 300 metres / 984 ft outdoors (depending on local conditions) |
| Microcontroller | |
| Processor | ESP-Shelly-C68F |
| Flash memory | 8 MB |
| Firmware features | |
| Schedules | Nu |
| Webhooks (URL actions) | 10 with 2 URLs per hook |
| Scripting | Nu |
| MQTT | Da |
| UDP | Da |
| KVS (key-value storage) | Da |
Shelly Flood S Gen4 is the right choice for anyone who wants to learn about a leak within the first seconds, not after the water has reached the neighbor's ceiling.