Rule Hi Water Bilge Alarm and Float Switch 12V (NSHWALARM) is a compact, reliable high-water monitoring solution built for unmanned compartments on boats and light commercial vessels. With a visual in-dash gauge and a loud 85 dB alarm, it delivers immediate, unmistakable alerts the moment water is detected.

This unit uses a non-mercury float switch and runs on 12V DC, making it easy to integrate into standard vessel electrical systems. One float switch is included in the box, and the design supports adding additional Rule Float Switches for other compartments as your protection plan grows.

• Non-mercury float switch for safer operation and simpler disposal
• In-dash gauge combines a clear visual indicator with a piercing 85 dB audible alert
• 12V DC operation for straightforward installation on most boats
• Includes (1) float switch; expandable by adding more switches for multiple compartments
• Complies with CFR 182.530, delivering required visual and audible alarms in unmanned spaces on commercial vessels at 26' (7.9 m) or longer

Why this matters: in an unattended space, silent water intrusion can escalate quickly. The Rule Hi Water Bilge Alarm gives you constant, proactive monitoring without the need for constant crew presence. The audible alarm and cockpit-ready gauge provide fast situational awareness, enabling you to respond before rising water becomes a threat.

Ideal scenarios include keel-walled bilges on sailboats, engine compartments, and other unmanned spaces where water intrusion risk exists. If your vessel has multiple compartments, simply add additional Rule Float Switches to extend protection without complicating the core system. Trusted by mariners who demand dependable, code-compliant high-water detection, this alarm helps you safeguard your hull, gear, and passengers.