Panasonic Water Leak Sensor KX-HNS103

Introduction

The Panasonic Water Leak Sensor KX-HNS103 is a reliable home monitoring accessory designed to detect water leaks early, helping to prevent costly water damage. Utilizing a small probe that senses moisture through electrical conductivity, this device alerts homeowners by triggering notifications, which can include smartphone alerts and hub beeps when connected with the compatible KX-HNB600 Hub system. Its wireless DECT 6.0 technology ensures secure and interference-free communication.

Ideal for homeowners, renters, and small business operators, this sensor is particularly useful in areas prone to water damage, such as basements, kitchens, bathrooms, and laundry rooms. Its wall-mountable design and 1.2-meter probe cable allow flexible installation on floors or walls, ensuring comprehensive coverage. The sensor features a long-lasting CR2 lithium battery providing up to two years of operation under typical usage conditions.

Available as part of Panasonic’s Home Monitoring System accessories, the KX-HNS103 typically ranges in price from $50 to $80, depending on the retailer and region. It is often sold separately but requires the KX-HNB600 Hub or an associated home monitoring kit for full functionality. With its user-friendly one-push pairing button and LED status indicators, the sensor offers seamless integration into existing Panasonic smart home ecosystems, making it a practical solution for early water leak detection.

Part names and functions

Main unit
Main unit cover
Used to confirm the status of the sensor or register the sensor to the hub.
LED indicator
Cable
Probe unit
Probes

Panasonic Water Leak Sensor KX-HNS103-Part names

Specifications

Standards
DECT 6.0 (Digital Enhanced Cordless Telecommunications 6.0)
Frequency range
DECT: 1.92 GHz – 1.93 GHz
RF transmission power
DECT: 115 mW (max.)
Power source
Lithium battery CR2 (1 ´ 3.0 V, 850 mAh)
Operating conditions
0 °C – 40 °C (32 °F – 104 °F)
Battery life
Approx. 2 years (when the sensor is triggered once a month, in an environment of 25 °C (77 °F))
Dimensions
Main unit (height ´ width ´ depth) (not including double-sided tape):
Approx. 106 mm ´ 31 mm ´ 22 mm (4 5/32 inches ´ 1 7/32 inches ´ 7/8 inches)
Probe unit (height ´ width ´ depth) (not including double-sided tape):
Approx. 44 mm ´ 24 mm ´ 10 mm (1 23/32 inches ´ 15/16 inches ´ 3/8 inches)
Cable (length):
Approx. 1.2 m (3 feet 11 inches)
Mass (weight)
Approx. 80 g (0.18 lb), excluding the battery

LED indicator

You can press and check the LED indicator to confirm the sensor’s status.
After confirming the sensor’s status, we recommend turning the LED indicator off by pressing M N again as soon as possible; otherwise, battery life may be reduced.

Note:
The LED indicator does not indicate sensor status if the sensor has not been registered (page 9).

Setup overview

Initial setup
Make sure you can access the system using your mobile device. For details, refer to the System Setup Guide included with your hub.
Insert the battery
The sensor is battery-powered.
Registration
Required only if the sensor was purchased separately (i.e., not as part of a bundle).
Confirm the usage area.
Read the information in this document to confirm that the desired installation area is suitable for proper operation.
Installation
Install the sensor in the desired location.

Confirming the usage area

Wireless communication range
The wireless communication range of each device in the system from the hub is approximately 50 m (160 feet) indoors and approximately 300 m (1,000 feet) outdoors. Wireless communication may be unreliable when the following obstacles are located between the hub and other devices.

Metal doors or screens
Walls containing aluminum-sheet insulation
Walls made of concrete or corrugated iron
Double-pane glass windows
Multiple walls
When using each device on separate floors or in different buildings

Installation

The main unit is installed on a wall, and the probe unit can be installed on a wall or a floor.
When the metal probes on the probe unit come into contact with water, a small amount of electrical charge flows between the probes, which the main unit recognizes as a water leak.

Installation precautions

The sensor is not designed to be used in situations that require high reliability. We do not recommend the use of the sensor in these situations.
Panasonic takes no responsibility for any injury or damage caused by the use of this product.
When installing, make sure the battery is inserted properly and the main unit cover is completely closed.
When installing on a wooden surface, use the included wall mounting adaptors.
Secure the wall mounting adaptors to the wall using screws (not double-sided tape).
Mount the sensor in a stable location where the sensor can be adequately supported when mounting.
Do not mount the sensor on a soft material. It may fall down, break,, or cause injury.
Do not mount the sensor on the following places: gypsum board, ALC (autoclaved lightweight cellular concrete), concrete block, plywood less than 25.4 mm (1 inch) thick, etc.
The sensor may not be able to properly detect a water leak if the water contains

Installation location

Install the water leak sensor in a basement, kitchen, utility room, or anywhere you want to detect a water leak. Common installation examples include near a washing machine, a hot water heater, or a location where a water leak has occurred in the past.

Note:

Install the probe unit so that its metal probes are about 1 mm (1/32 inches) above the floor. If the probes touch the floor, the sensor may make false detections. If the probes are too far from the floor, water leaks can only be detected after the leaked water has become deep enough to touch the probes.
Install the main unit 1 m (3 feet 3 inches) or higher above the floor. The main unit is not waterproof; if it becomes wet, the sensor may become damaged,, and water leaks will not be detected properly.

Panasonic Water Leak Sensor KX-HNS103-Installation location

Features available when using the[Home Network] app

Some of the sensor’s features that are available when using the [Home Network] app are listed below. For more information, refer to the User’s Guide (page 18).

Alarm system
You can use the app to arm and disarm the alarm system, confirm the current status of the sensor, and view a log of previous events.
Sensor integration
You can configure the sensor to trigger other system events, such as camera recording, turning on an electric device (such as a lamp), etc. (Appropriate device required.)
Telephone alert
You can configure the system to call a preprogrammed phone number when the sensor is triggered.

Troubleshooting the Panasonic Water Leak Sensor KX-HNS103

Common issues with the Panasonic Water Leak Sensor KX-HNS103 include false alarms, connectivity problems, and battery depletion. False alarms may occur if the probe contacts condensation or high humidity, which can be mitigated by installing the sensor away from such areas or ensuring the probe is not exposed to non-leak moisture.

If the sensor does not communicate with the hub, verify that the DECT wireless range (1.88-1.93 GHz) is clear of interference and that the sensor is within effective distance (usually within 50 meters indoors). Press the one-push pairing button to re-establish the connection if necessary.

Error codes are minimal, but a steady red LED typically indicates a triggered leak detection, whereas a blinking LED can signify a low battery. Replacing the CR2 lithium battery promptly will prevent loss of functionality. Preventive maintenance includes regular battery checks and ensuring the probe and sensor housing remain dry and clean.

Panasonic offers a limited warranty, generally one year from purchase, covering manufacturing defects. For support, users can contact Panasonic Customer Service via their official website or regional helplines. Online manuals and FAQs provide additional guidance for installation and troubleshooting.

Warranty (For the United States and Puerto Rico)

Panasonic Home Network System Products Limited Warranty

Limited Warranty Coverage
If your product does not work properly because of a defect in materials or workmanship, Panasonic Corporation of North America (referred to as “the warrantor”) will, for the length of the period indicated on the chart below, which starts with the date of original purchase (“Limited Warranty period”), at its option either (a) repair your product with new or refurbished parts, or (b) replace it with a new or a refurbished equivalent value product, or (c) refund your purchase price. The decision to repair, replace,, or refund will be made by the warrantor.

Home Network System Products microSD card (Included model only)

Parts: One (1) Year 90 days
Labor: One (1) Year N/A

During the “Labor” Limited Warranty period, there will be no charge for labor. During the “Parts” Limited Warranty period, there will be no charge for parts. You must mail your product prepaid during the Limited Warranty period. This Limited Warranty excludes both parts and labor for batteries, antennas, and cosmetic parts (cabinet). This Limited Warranty only applies to products purchased and serviced in the United States or Puerto Rico. This Limited Warranty is extended only to the original purchaser and only covers products purchased as new.

Pros and Cons of Panasonic Water Leak Sensor KX-HNS103

Pros:
- Highly sensitive water detection with a small probe for early alerting.
- Long battery life up to 2 years reduces maintenance.
- Wireless DECT 6.0 technology ensures a secure and stable connection.
- Easy installation with a wall-mountable design and a one-push pairing button.
- Integration with the Panasonic Home Monitoring System enables smart alerts on smartphones and cordless handsets.
Cons:
- Requires Panasonic KX-HNB600 Hub or compatible system; not a standalone device.
- Limited to indoor use within°Ca 0°°C C to 40°C operating temperature range.
- Probe cable length (1.2m) might constrain placement in larger areas.
- Not recommended for high-reliability industrial or commercial water detection needs.

Compared to alternatives, such as standalone Wi-Fi water sensors, the Panasonic KX-HNS103 offers better integration within a full smart home ecosystem but lacks independent functionality. Its price point provides good value for existing Panasonic system users who want reliable, simple water leak detection.

Customer Reviews of Panasonic Water Leak Sensor KX-HNS103

Users generally praise the Panasonic Water Leak Sensor KX-HNS103 for its prompt leak detection and seamless connectivity within Panasonic’s home monitoring setup. Many highlight the convenience of receiving smartphone alerts and the long battery life as key benefits. The sensor’s compact design and easy installation are also frequently commended.

However, some customers report occasional false alarms triggered by condensation or environmental moisture and note that the device must be paired with the Panasonic hub, which adds to the overall system cost. The limited probe length has been mentioned as a minor inconvenience for larger spaces.

Overall, the product averages around 4 out of 5 stars in user ratings. Buyers recommend it primarily for those already invested in Panasonic’s smart home ecosystem or seeking an affordable water leak sensor that integrates with other home monitoring devices.

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