- New
Product description: LoRaWAN IP67 mini spot flood sensor - Milesight WS303
The Milesight WS303 is a modern, miniature point flood sensor that automatically sends alerts upon detection of water or other conductive liquids using the LoRaWAN protocol. A 590 mAh lithium battery provides up to 5 years of operation without requiring replacement. The sensor is equipped with a local audible alarm (buzzer) and can operate in direct D2D mode, allowing for ultra-fast response without the need for a LoRaWAN gateway . The IP67 -rated housing protects the device in demanding environments.
Main features of the Milesight WS303 flood sensor
- Liquid detection from a level of 0.5 mm : immediate reaction to flooding
- Audible alarm : built-in buzzer for local warning
- LoRaWAN and Milesight D2D connectivity : wireless transmission and communication without a gateway
- NFC setup : quick pairing with the mobile app
- 5 years of operation on a single battery : low energy consumption and wireless
- IP67 housing : waterproof and dustproof in harsh environments
- Integration with Milesight IoT Cloud : data visualization and remote management
Reliable leak detection thanks to precise technology
The Milesight WS303 is a miniature flood sensor that uses the electrical conductivity of liquids to detect the presence of water as low as 0.5 mm . Two gold-plated metal contacts create a circuit upon contact with the liquid, immediately triggering a local audible signal and an alarm transmitted via the LoRaWAN network . This allows the sensor to quickly respond to uncontrolled leaks, flooded floors, or plumbing leaks. A built-in buzzer provides immediate warning to the user, even without network access. Additionally, the device supports Device-to-Device (Milesight D2D) operation , enabling instant communication with other system components without the use of a LoRaWAN gateway .
LoRaWAN and NFC connectivity - flexible integration with IoT systems
The sensor enables communication distances of up to 2 km in urban areas and up to 15 km in open spaces. Thanks to its low power consumption, it can operate for up to 5 years on a single 590 mAh CR2450 battery (based on 1 hour of flood detection per week). Configuration is performed via NFC with the Milesight ToolBox app , making the entire commissioning and update process quick and convenient. The sensor works with any standard LoRaWAN gateway and can be remotely monitored and managed via the Milesight IoT Cloud platform.
IP67 resistant design and easy, tool-free installation
The WS303 is designed for harsh environments. Its IP67-rated housing provides protection against water and dust, allowing installation even in damp rooms. Its compact size (63 x 63 x 14 mm) allows the sensor to fit virtually anywhere – under a washing machine, dishwasher, in a cabinet, or near pipes. Installation is wireless and requires no drilling using double-sided 3M tape . Stainless steel components and gold-plated contacts ensure long life and corrosion resistance . It's ideal for both home and industrial use.

In the event of a water leak, the sensor will trigger an alarm and send a notification to your smartphone.
Smart applications in homes and offices
The WS303 sensor is suitable for use in bathrooms, kitchens, basements, public restrooms, server rooms, and industrial installations . It integrates seamlessly with smart building infrastructure and can be part of complex automation scenarios, such as activating shut-off valves, sending alerts to phones, or activating traffic lights. Thanks to its MQTT, API, and LoRaWAN compatibility , it can be easily integrated with other IoT systems. When combined with the Milesight IoT Cloud , it offers data visualization, automated reports, and real-time alerts, enabling rapid response and reducing flood-related losses.
Technical specifications of the flood sensor
- Technology: LoRaWAN, Milesight D2D
- Frequency range: EU868
- Receive sensitivity: -137 dBm @ 300 bps
- Transmission modes: OTAA, ABP (class A)
- Liquid detected: conductive
- Detection level: from 0.5 mm
- Alarm: built-in buzzer
- Configuration: NFC (mobile app)
- Power supply: 1x CR2450 590 mAh (replaceable)
- Battery life: up to 5 years (at 1 hour of measurement / week, 25°C)
- Operating temperature range: -10°C to 60°C
- Relative humidity: 0% RH to 100% RH
- Tightness class: IP67
- Housing material: ABS + PC, white
- Mounting: 3M tape, horizontal surface
- Dimensions: 63 x 63 x 14 mm
- Weight: 36.4 g
Contents of the set
- 1x WS303 Sensor
- 1x CR2450 battery
- 2x 3M mounting tape





