How Apple Watch Ejects Water From Its Speaker (And How to Do It on Any Phone)

Apple Watch has a clever feature called Water Lock. Here's how it works and how to replicate it on any device.

Water Lock: The Science

When you exit Water Lock mode, the Apple Watch plays a ~165Hz tone through its speaker. This specific frequency causes the tiny speaker diaphragm to oscillate rapidly enough to overcome the surface tension holding water droplets inside the speaker grille.

The result: water gets physically pushed outward through the mesh. You can actually see tiny droplets fly off the watch when this happens.

Why 165Hz?

The 150-200Hz range is the sweet spot because:

• The wavelength matches typical speaker grille cavity dimensions
• It creates optimal diaphragm displacement
• The oscillation is fast enough to break water surface tension
• But gentle enough not to damage the speaker

Replicating This on Any Phone

The same physics applies to any speaker. A free web tool at fixspeaker.com implements a 30-second frequency sweep from 150-200Hz.

Steps:

1. Open fixspeaker.com
2. Turn volume to maximum
3. Press Eject Water
4. Hold the device with speaker facing down
5. Repeat 2-3 times

The Web Audio API Behind It

const ctx = new AudioContext();
const osc = ctx.createOscillator();
osc.type = 'sine';

// Sweep through the effective frequency range
osc.frequency.setValueAtTime(150, ctx.currentTime);
osc.frequency.linearRampToValueAtTime(200, ctx.currentTime + 30);

osc.connect(ctx.destination);
osc.start();
setTimeout(() => osc.stop(), 30000);

The key insight is using a sweep rather than a fixed tone. Different speaker sizes resonate at slightly different frequencies within the 150-200Hz range, so sweeping ensures you hit the optimal frequency for any device.

Results

Tested across iPhone 15, Pixel 8, Samsung S24, MacBook Air:

• Submersion recovery: 1-2 cycles
• Rain/splash: 1 cycle
• Steam/humidity: 2-3 cycles

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The next time someone tells you to put your wet phone in rice, show them this instead.