Shelly Flood S Gen4

Shelly Flood S Gen4 Smart Water Leak Sensor | Matter & Zigbee

Catch leaks early and protect your property with the Shelly Flood S Gen4 Smart Water Leak Sensor. This compact, battery-powered sensor uses large-surface stainless-steel detection pads to identify water quickly and reliably—even clean or low-conductivity water.

Its low-profile, IP67-rated design makes it ideal for positioning under appliances, beneath sinks, near plumbing fixtures or inside drip pans. With Wi-Fi 6, Bluetooth 5 LE, Zigbee 3.0 and Matter-over-Wi-Fi connectivity, it can deliver alerts and trigger smart-home automations through Shelly Cloud, Home Assistant and other compatible platforms.

Key Features

• Reliable leak detection: Large stainless-steel contact pads detect clean and low-conductivity water.
• Flood and Rain modes: Choose the appropriate operating mode for indoor leak protection or outdoor rain-based automations.
• Three alarm profiles: Select Intense, Normal or Economic mode to suit the location and level of protection required.
• Built-in audible alarm: The integrated buzzer provides an immediate local warning when water is detected.
• IP67 protection: Designed for reliable operation in wet and demanding environments.
• Long battery life: Powered by one included CR2477 battery for convenient wireless operation.
• Multiple connectivity options: Supports Wi-Fi 6, Bluetooth 5 LE and Zigbee 3.0.
• Matter support: Matter-over-Wi-Fi provides streamlined integration with compatible smart-home ecosystems.
• Local automation actions: Create responsive automations without relying entirely on cloud services.
• Broad platform compatibility: Integrates with Shelly Cloud, Home Assistant, Amazon Alexa, Google Home, Samsung SmartThings and other compatible platforms.

Flood and Rain Detection Modes

Flood Detection Mode

Detects a change in water status and immediately activates the selected alarm profile. This mode is recommended for kitchens, bathrooms, laundries, plant rooms, server rooms and other areas where a leak requires urgent attention.

Rain Detection Mode

Detects the presence of water without activating the flood alarm. It is ideal for outdoor automations such as pausing irrigation, closing skylights or windows, and controlling motorised awnings.

Selectable Alarm Profiles

• Intense: Frequent reporting and an extended audible alarm for high-value or critical areas, including server rooms and laboratories.
• Normal: The default profile for everyday residential and commercial leak protection.
• Economic: Disables the buzzer and conserves battery power, making it suitable for holiday homes, cabins and locations that may remain unattended.

Popular Applications

Immediate Flood Detection

Receive rapid alerts in kitchens, bathrooms and laundry rooms, allowing you to respond before water damage spreads.

Under-Appliance Protection

Slide the low-profile sensor underneath washing machines, dishwashers, refrigerators and other water-connected appliances.

Under-Sink and Valve Monitoring

Position it beneath P-traps, water filters, shut-off valves and flexible hoses to detect slow drips before they cause hidden damage.

Toilet Leak Detection

Place the sensor besides or behind a toilet to monitor supply lines, cisterns and base seals.

Water Heater and Boiler Pans

Install it inside a drip pan to receive an alert if the pan begins to fill or overflow.

Automatic Water Shutoff

Pair the sensor with a compatible smart water valve and automation platform to shut off the water supply automatically when a leak is detected.

Rain-Based Automations

Use Rain Detection Mode to trigger compatible outdoor automations, including irrigation control, motorised awnings and skylight or window closure.

Automatic shutoff and other automation functions require separately sold compatible devices and appropriate platform configuration.

Suitable For

• Homes and apartments
• Hotels, condominiums and multi-dwelling developments
• Small offices, shops and restaurants
• Government and municipal facilities
• Universities, colleges and laboratories
• Farms and agricultural facilities
• Server rooms and equipment areas

Smart-Home Integrations

• Amazon Alexa: Contact Sensor capability
• Google Home: Sensor State capability
• Samsung SmartThings: Battery and Water Sensor capabilities
• Home Assistant: Compatible integration options for monitoring and automation
• Shelly Cloud: Remote monitoring, alerts and automation
• MQTT, UDP and Webhooks: Advanced local and third-party integration options

Button Controls

• Press once: Wakes the sensor for three minutes and initiates a status report.
• Press twice rapidly: Returns the device to sleep.
• Press three times rapidly: Activates Zigbee inclusion mode for three minutes.
• Press five times rapidly: Switches between the default Matter firmware and Zigbee mode.
• Hold for five seconds: Initiates a network reset.
• Hold for ten seconds: Restores factory settings.

Audible and LED Indications

Buzzer

• Long repeating beep: Flood detected.
• Short repeating beep: Battery level below 20%.

LED

• Blue: Access Point mode enabled.
• Red: Wi-Fi station mode active but not connected.
• Yellow: Connected to Wi-Fi but not Shelly Cloud, or cloud access is disabled.
• Green: Connected to Wi-Fi and Shelly Cloud.
• Flashing purple: Zigbee commissioning mode.
• Flashing red and blue: Firmware update in progress.
• Flashing yellow: Device identification mode.

Technical Specifications

Frequently Asked Questions

Why doesn’t the sensor detect water instantly?

To extend battery life, the Shelly Flood S Gen4 checks for a change in flood status every five seconds. This brief delay balances responsive detection with efficient battery operation.

How can false alarms be reduced in humid environments?

Increase the State Hold Time setting. It is set to zero by default and can be adjusted up to 60 seconds. The flood state will then change only when the same condition remains present for the selected period.

What’s Included

• 1 × Shelly Flood S Gen4
• 1 × CR123A battery
• User documentation