Is there a Waterproof Rating for Rain Suits?

Is there a waterproof rating for rain suits? Or do we just trust the maker? Or do we keep changing them until we find one that works? And NO, THIS IS NOT A PAID OR SPONSORED ARTICLE.

We admit, buying a motorcycle rain suit is not an easy task, especially when every maker claiming to make the best rain suit, usually along the lines of being “fully waterproof” and “breathable.” Just head to online shopping platforms such as Shopee and Lazada and you will see what mean. (And we have not begin to touch on fake ones yet.)

So, back to the question: Is there such a rating? Well, yes.

Fabric waterproof ratings
Waterproof Rating (Water column in mm)  Level of water resistance Conditions
0-5000 mm No resistance to some resistance to moisture. Light rain, no pressure.
6000-10000 mm Rainproof and waterproof under light pressure. Light rain, light pressure.
11000-15000 mm Rainproof and waterproof except under high pressure. Moderate rain, light pressure.
16000-20000 mm Rainproof and waterproof under high pressure. Heavy rain, some pressure.
20000 mm+ Rainproof and waterproof under very high pressure. Heavy rain, high pressure.

Please refer to the table above.

So, the higher the water column rating, the more waterproof that fabric is.

“Pressure” as described above is the force which presses the water column against the fabric, which simulates wind. This is why certain rain suit and/or winter clothing makers specify their fabrics’ waterproof rating in PSI (pressure per square inch). The conversion rate is 1 psi = 704 mm of water.

How is the fabric tested?

The technical term is hydrostatic pressure test.

First, there is a reason why the rating is called “water column.” It refers to a vertical tube filled with water and graduated in mm, thus resembling a column.

Photo from

A piece of fabric is pulled taught, like the skin of a drum, and the tube is placed on top of it. Water is then added into the tube until its pressure permeates through the fabric.

For example, if water starts to permeate at 3250mm, that particular fabric has a waterproof rating of between 0-5000mm, hence it is somewhat resistant to water and suitable for very light rain.

Photo from

Simple so far.

Problem is…

However, not all manufacturers publish their rain suits’ rating. There are those who mimic (ahem) or utilise the same materials used by other manufacturers to create their own.

There are several resulting eventualities here:

  • A rain suit that has no waterproof rating, but is really waterproof due to good materials and design. You will be surprised to find certain branded rain suits that are rather thin and light yet offers great waterproofing and lasts for many years.
  • A rain suit that not only lets water in, but it is as much water as not wearing a rain suit. It could be due to a bad design such as no velcro seal, no “rain channel” to cover the jacket’s zipper, or bad seam seals (especially in the crotch area), or bad materials, or the combination of any or all these factors. And good luck trying to get your money back from the Shopee seller you ordered from!
  • But… there are also manufacturers who actually tested their rain suits yet they leak like a sieve. Clock these up to bad design and materials.
So how do we know?

The best bet, unfortunately, is to experiment with rain suits from several brands. Our favourites thus far are from RS Taichi and Komine. The former does not have its waterproof rating published, while the Komine’s level is 32000mm. They are light, long lasting, breathable, and very waterproof. NO, THIS IS NOT A PAID ARTICLE, instead it is from our own experiences of having owned several rain suits.

Wahid's lust for motorcycles was spurred on by his late-Dad's love for his Lambretta on which he courted, married his mother, and took baby Wahid riding on it. He has since worked in the motorcycle and automotive industry for many years, before taking up riding courses and testing many, many motorcycles since becoming a motojournalist. Wahid likes to see things differently. What can you say about a guy who sees a road safety message in AC/DC's "Highway to Hell."

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