Compact LoRaWAN® Water Leak Sensor for Smart Buildings & Critical Areas
The Milesight WS303 is a compact and reliable LoRaWAN® Mini Leak Detection Sensor, designed to detect the presence of conductive liquids and send instant alarms when a water leak occurs. Its small size and wireless design make it ideal for smart buildings, server rooms, offices, museums, laboratories, archives, cold storage areas and residential applications.
The WS303 uses a small water probe to detect conductive liquids. Once the liquid level reaches approximately 0.5 mm, the sensor triggers an alarm and transmits the event through a LoRaWAN® network. This enables early detection of leaks before they cause serious damage to equipment, infrastructure or valuable assets.
In addition to remote alerts, the WS303 includes a built-in buzzer for local real-time alarm notifications. It also supports Milesight D2D communication, enabling direct low-latency interaction with other Milesight devices, such as controllers for automatic valve shutoff, even without relying on a gateway.
With an IP67 waterproof enclosure, NFC configuration via the Milesight ToolBox app and a replaceable 590mAh CR2450 lithium battery with up to 5 years of battery life, the WS303 provides a practical and low-maintenance solution for water leak detection in demanding environments.
Key Features
✔ Compact LoRaWAN® Water Leak Sensor
✔ Detects Conductive Liquids
✔ 0.5 mm Leak Detection Trigger Level
✔ Built-in Buzzer for Local Alarm
✔ Milesight D2D Communication
✔ NFC Configuration via Smartphone
✔ IP67 Waterproof Enclosure
✔ Replaceable 590mAh CR2450 Battery
✔ Up to 5 Years Battery Life
✔ Compatible with Standard LoRaWAN® Gateways
✔ Ideal for Server Rooms, Museums & Smart Buildings
✔ Easy Installation with 3M Tape
Typical Specifications
• Wireless Technology: LoRaWAN® / Milesight D2D
• LoRaWAN Mode: OTAA / ABP Class A
• Frequency Bands: EU868 / US915 / AU915 / AS923 / IN865 / KR920 / CN470 / RU864
• Liquid Type: Conductive Liquid
• Trigger Condition: Liquid Level Reaches 0.5 mm
• Power Supply: 1 × 590mAh CR2450 Lithium Battery
• Battery Life: Up to 5 Years
• Configuration: NFC / LoRaWAN Downlink
• Alarm: Built-in Buzzer
• Protection Rating: IP67
• Installation: Surface Placement / Wall Mount with 3M Tape
Applications
Server Rooms & Data Centers
Smart Restrooms
Laboratories
Libraries & Archives
Cold Storage Areas
Museums
Offices & Commercial Buildings
Residential Leak Detection
Water Pipe Monitoring
Smart Building Automation
Package Includes
✔ 1 × Milesight WS303 Mini Leak Detection Sensor
✔ 1 × CR2450 Battery
✔ 2 × 3M Tapes
✔ Quick Start Guide / Warranty Card
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Product Downloads
- Model: WS303
- Type: Mini Leak Detection Sensor
- Wireless Technology: LoRaWAN® / Milesight D2D
- LoRaWAN Mode: OTAA / ABP Class A
- Frequency: EU868 / US915 / AU915 / AS923 / IN865 / KR920 / CN470 / RU864
- Liquid Type: Conductive Liquid
- Trigger Condition: Liquid level reaches 0.5mm
- Alarm: Built-in buzzer + LoRaWAN® alarm
- Power Supply: 1 × 590mAh CR2450 Lithium Battery
- Battery Life: Up to 5 years
- Configuration: NFC / LoRaWAN Downlink
- Protection: IP67
















