Abstract: The present invention relates to a portable water safety monitoring device including a transmitter to be worn on a person, and a base station for monitoring any transmission from the transmitter indicating immersion of the transmitter in water. The device is particularly applicable for monitoring children near a swimming pool or other body of water to prevent drowning accidents. The transmitter is a compact printed circuit board carrying a capacitance water sensor and a sealed circuitry for detecting a change in capacitance and transmitting an alarm signal to the base station. Advantageously, on opposing sides of the printed circuit board large perimeter conductors provide a sensor able to register a varying level of capacitance. This can reduce false alarms due to incidental wetting. As a further advantage, the use of a compact printed circuit board eliminates any exposed leads in the construction, which could be damaged or disconnected by a child deactivating the monitor.