IP Ratings for Outdoor Sensors: What IP65, IP67 and IP68 Actually Mean

IP67 is not better than IP65. It's different, and in one common situation it's worse.

That surprises most buyers, because the numbers look like a ladder. They aren't. The second digit describes which specific test the enclosure passed, and passing the immersion test doesn't mean passing the pressure jet test.

Get this wrong and you buy a sensor rated for submersion, mount it in a wash-down area, and destroy it the first time someone points a hose at it.

What the two digits mean

An IP rating has two numbers. The first covers solids, the second covers liquids.

First digit: solid particle protection

For outdoor sensors, 5 or 6 is what you want. Below that you're into indoor equipment.

Second digit: liquid ingress protection

So IP65 means dust protected and jet resistant. IP67 means dust tight and immersion resistant. IP68 means dust tight and rated for continuous submersion at a stated depth.

Why higher is not automatically better

Here is the part that catches people out.

IP67 devices are tested for immersion, not for jets. A sealed enclosure can survive sitting in still water at low pressure and still fail against a pressure washer, because a directed jet applies far more localised force than a metre of static water.

If your sensor sits in a food processing area, a dairy, a vehicle wash bay or anywhere that gets cleaned with a hose, IP65 or IP66 is the rating that matters, not IP67. The jet test is the relevant one.

If your sensor might sit in standing water after heavy rain, or gets buried, or drops into a tank, IP67 or IP68 is what you need.

Some devices carry both, written as IP66/IP68. That's the manufacturer telling you it passed two separate test regimes, and it's genuinely more capable than either alone.

The practical question isn't "what's the highest rating I can get." It's "what is water going to do to this device, and which test matches that."

What an IP rating does not cover

The rating tests one thing, under laboratory conditions, with clean, fresh water. Several outdoor failure modes sit entirely outside it.

UV degradation. Plastics chalk, embrittle, and crack after years of sun. Nothing in the IP test says anything about it, and it's the most common cause of enclosure failure on multi-year outdoor deployments.

Condensation. A sealed enclosure that heats in the day and cools at night will condense internally. The water didn't get in from outside, it was always in there as vapour. IP68 doesn't help.

Corrosion. IP tests use fresh water. Salt air, fertiliser, cleaning chemicals, and livestock housing ammonia all attack seals and contacts in ways the test never simulates. Coastal and agricultural deployments age faster than the rating suggests.

Temperature cycling. Repeated expansion and contraction work seals loose over time. A rating is a point-in-time test result, not a lifespan.

The honest way to read an IP rating is as a minimum specification for a new device, not a guarantee for year five.

Which rating for which deployment

Note that wind-driven rain is closer to a jet than to splashing, which is why IP65 rather than IP54 is the sensible floor for anything genuinely exposed.

Where enclosures actually fail

Almost never through the body. Nearly always at one of four points.

Cable glands. The most common failure by a wide margin. A gland tightened by hand, or one sized for a different cable diameter, will leak regardless of what the enclosure body is rated for.

Cable entry orientation. Bring a cable in from above and water runs down it into the gland. Bring it in from below, or form a drip loop, and gravity works for you instead.

Lids opened and reclosed. Every time an enclosure is opened for maintenance, the seal is a reinstallation. Pinched gaskets, missed screws, and grit on the sealing face all undo the rating.

Unused ports. A spare gland left open is a hole. Blank it.

An IP67 enclosure with a badly fitted gland performs worse than an IP54 enclosure with a good one. The rating describes the enclosure as tested, not as you installed it.

When the rating isn't published

Plenty of sensors ship without a stated IP rating. That doesn't automatically mean it's poor, but it does mean you're buying on faith.

Ask the supplier directly, and ask for the specific rating rather than a description. "Waterproof" and "weather resistant" are marketing terms with no defined test behind them. IP65 is a test result.

If a supplier can't give you a figure, treat the device as suitable for sheltered positions only, and add protection yourself. An IP65 outdoor bag or enclosure around a device with no rating of its own is a legitimate way to deploy hardware that wasn't designed for exposure, provided the cable entries are handled properly.

For anything going into a location where replacement means a site visit, get the number in writing before ordering.

Match the rating to the water, not to the number

The buyers who get this right ask one question before ordering: what is water going to do to this device? Rain, jets, immersion, and humidity are four different problems, and only one of them is solved by the highest number on the list.

Check the rating on any external sensor before it goes outside, and look through accessories for the enclosures, bags, and cases that let you deploy hardware in conditions it wasn't built for.

Not sure what your site will throw at a sensor? Describe the location to us at UbiBot USA, and we'll tell you the rating you need and whether protection is worth adding. It's a cheaper conversation than a replacement.

Frequently asked questions

Is IP67 better than IP65? 

Not universally. IP67 is tested for temporary immersion, IP65 for water jets. In a wash-down environment, IP65 or IP66 is the relevant rating, because a pressure jet applies more localised force than static immersion. Choose the rating that matches the water exposure you actually have.

What does the first digit in an IP rating mean? 

Solid particle protection. For outdoor sensors, you want 5 (dust protected) or 6 (dust tight). Anything lower is indoor equipment.

Can an IP68 device be pressure washed? 

Not necessarily. IP68 covers continuous immersion, not directed jets. Look for a device rated IP66/IP68 or check the manufacturer's guidance, because the two tests are separate.

Does an IP rating cover UV and sun damage? 

No. IP testing covers solids and water only. UV degradation, condensation, corrosion, and temperature cycling all sit outside it, and all of them cause outdoor enclosure failures over time.

What IP rating do I need for a buried soil sensor? 

IP67 as a minimum, IP68 if the ground stays saturated or floods. Buried sensors sit in prolonged contact with wet soil, which is closer to immersion than to rain.

Why did my IP65 sensor still get water inside? 

Almost always the cable gland or the lid seal rather than the enclosure body. Check gland tightness and cable diameter, form a drip loop so water runs away from the entry rather than into it, and blank any unused ports.