Why IP68 Enclosures Still Suck Up Water – And What You Can Do About It

It’s a common misconception in the electronics and outdoor enclosure world: “My project is safe because I’m using an IP68-rated enclosure.” Unfortunately, that sense of security often proves false. Despite the high ingress protection rating, IP68 enclosures can – and often do – absorb water over time. Here’s why.

What IP68 Really Means

An IP68 rating means the enclosure is dust-tight (first digit 6) and can withstand continuous immersion in water beyond 1 meter (second digit 8). But here’s the catch: this rating is tested under controlled conditions – static pressure, clean water, a short time span, and a brand-new, perfectly sealed unit.

What the rating doesn't account for is:

  • Thermal cycling (daily heating/cooling)
  • Air pressure changes (weather or altitude)
  • Long-term exposure
  • Mechanical stress or minor deformations

And this is exactly where the problem begins.

The Water-Vapor Trap

Every time your sealed enclosure heats up during the day (due to sun exposure, internal electronics, or ambient heat), the air inside expands. If there’s no way for that pressure to release, the enclosure starts to deform slightly – or air may escape via the tiniest leaks.

Then, when the temperature drops at night, the internal pressure drops, and the enclosure tries to suck in outside air to equalize the pressure. If the enclosure is perfectly sealed, this causes vacuum stress. But in reality, most “sealed” enclosures aren’t perfect. They suck in tiny amounts of air – and moisture with it.

Do this enough times, and the internal humidity rises until condensation forms or free water pools at the bottom.

Why Gaskets Aren’t Always Enough

Standard silicone gaskets or molded seals often lose flexibility over time. Worse yet, many are not chemically compatible with specific environments (e.g., salt spray, oils, or UV). Over time, they degrade or allow micro-leaks.

Unless you’re using:

  • Custom-cut gaskets designed to compress evenly across the enclosure
  • Proper torque control on fasteners, and
  • Consistent gasket compression around the entire seal,

...your IP68 enclosure will slowly inhale humid air and eventually get wet inside.

Additionally, for every connector, bolt, or custom component sticking out of the enclosure (such as UHF connectors, cable glands, or mounting screws), you need custom gaskets or sealing measures tailored to that part. If not properly sealed, these points act as capillary paths for moisture. For example, in baluns without dedicated gasket seals, water will eventually ingress through screws, bolts, or coax connectors.

The Critical Role of a Compression/Pressure Valve

A hydrophobic pressure relief valve (also called a breather valve or vent plug) is the missing piece. These small but essential components allow:

  • Air pressure to equalize through a semi-permeable membrane,
  • Water and dust to stay out, thanks to PTFE or ePTFE membranes,
  • Moisture to evaporate, preventing long-term buildup.

With the right valve, your enclosure can “breathe” safely and eliminate the pressure differential that causes it to suck in water through seals or microcracks.

The Bottom Line

IP68 does not mean waterproof for life. Without a pressure compensation solution, every temperature change turns your enclosure into a mini vacuum pump – one that slowly draws in humidity and eventually water.

If you want long-term protection, especially outdoors, always use:

✅ Custom gasket solutions with high compression recovery
✅ Torque-managed enclosure fasteners
✅ A pressure relief valve designed for your enclosure volume

Water always finds a way. It's up to you to stop it.

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Written by Joeri Van Dooren, ON6URE – RF, electronics and software engineer, complex platform and antenna designer. Founder of RF.Guru. An expert in active and passive antennas, high-power RF transformers, and custom RF solutions, he has also engineered telecom and broadcast hardware, including set-top boxes, transcoders, and E1/T1 switchboards. His expertise spans high-power RF, embedded systems, digital signal processing, and complex software platforms, driving innovation in both amateur and professional communications industries.