USP Water Level Sensor


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WARNING: Cancer and Reproductive Harm –


Detects The Presence Or Absence Of Water

The USP Water Level Alarm Sensor is used to detect the presence or absence of water, depending on your desired configuration. The water level alarm sensor (NO/NC) connects to a USP alarm panel or automatic voice dialer, and triggers an alarm when a high or low water level is detected. The automatic water level indicator is perfect for detecting leaks before they cause significant damage, or for detecting low water conditions in a fish tank or pet bowl.

  • Activates with the presence or absence of water
  • Detects water leaks to help prevent property damage
  • Detects low water conditions in fish tanks, pet bowls, etc.
  • Works with a USP alarm panel or automatic voice dialer


  1. This automatic water level indicator is designed for use with other USP products, such as the United Securities Dialer. Compatibility with third-party brands is not guaranteed.
  2. Not intended to be submerged in water.

United Security – Robust, Rugged, Ready

United Security Products (USP) has supplied quality products to the security alarm industry for more than 40 years, with proven performance in more than 100 million installations. Security systems professionals rely on USP for the most innovative products in the security industry. For your next installation, be sure to specify USP products.


  • Sensor Dimensions: ½ x ½ x 2½ inches
  • Leads: 24 inches

WLS Operating/Installation Instructions

  1. Mount the sensor (WLS) where monitoring is needed, i.e., on the floor or the wall at the height where the water notification is desired.
  2. Connect the wires to the alarm output:
    • Black wire to the positive or normally open connection. Red wire to the negative or common connection.
  3. The sensor is now ready to detect flooding, when the water reaches the level of two terminals, the alarm will activate.
  4. How to connect for a dry contact:
    • Normally Open application
    • Black wire to Normally Open contact (N/O)
    • Red wire to Common contact
    • Normally Closed application
    • Black wire to Common contact
    • Red wire to Normally Closed contact (N/C)

Note: When using United Security voice/pager dialers, use the Normally Closed application.
Note: ELK924 Sensitive Relay required when connecting to alarm panels.