What is a Good Waterproof Rating for Tents?

What is a Good Waterproof Rating for Tents Explained

1,500 mm, 3,000 mm, 10,000 mm: if you want to buy a new camping or trekking tent, you will find these numbers everywhere. No wonder: It’s about the water column of the tent.

But what does it say? What is good? What bad? Here are the answers to all these questions…

First of all: the water column of the tent basically reflects its water resistance which provides the inscriptions on how much water the tent can withstand without it dripping through. So far so good.

As a layman, you won’t understand anything at first. 1,000 mm? 5,000 mm? 10,000 mm? How much “water column” (WS) does your new camping or hiking tent have to have? This is exactly what this guide should explain to you. Also, we will figure out what is a good waterproof rating for tents.

How is the water column measured?

The unit of measurement for the water column in a tent is the millimeter (mm). How many millimeters of water the tent fabric can withstand until it lets the water through.

The measurement of the water column is therefore quite simple. The manufacturers fill a measuring cylinder with water under which 10 cm³ of tent fabric is stretched.

The manufacturers “start” with 100 ml in the cylinder. This amount is increased by another 100 ml every minute. If the first three (!) Drops appear on the inside of the fabric, the limit (= water column) has been reached. So it’s more about the pressure that the water needs to penetrate the fabric.

The manufacturers specify this pressure in mm instead of bar. After all, the simple rule of thumb applies here: the more, the better. Because when it rains you want to stay dry in your tent. Or not?

What is a Good Waterproof Rating for Tents?

But from what value is a water column “good”? What does 3,000 mm mean? Good? Bad? These categories help …

1,500 mm water column

1,500 mm water column is the minimum standard for tents, which is considered “tight” all over the world.

However, hiking tents with this water column cannot withstand continuous rain. Because if it rains continuously, more than 1,500 mm of water can “hit” the tent.

Consequence: It’s raining though. Nevertheless, a tent with 1,500 mm WS suffices for summer or southern regions (Italy, Spain).

2,000 mm water column

2,000 mm is more than 1,500 mm. But 2,000 mm is not top yet. For short trekking tours, in summer and Central Europe or North America, this value is definitely sufficient.

But the same applies here: You don’t want to experience continuous rain in such a tent. So check the weather for the next few days before your tour.

3,000 mm water column

Better: a water column of 3,000 mm. You can use such tents for longer tours without hesitation.

5,000 mm water

Column, After all, a water column of 5,000 mm or more is considered a premium. These tents are waterproof even in extreme weather. Whether in the far north or in rainy regions, with 5,000 mm you rarely have trouble. But: This “premium” is also paid for by the manufacturers.

Attention: Premium is not a must. 3,000 mm water column means that 3 m (!) Of water can “stand” on your tent. The tent is still tight. Because it’s about hydrostatic pressure.

Water column tent: what does the legislature say?

If you want to be on the safe side while camping or hiking, pay attention to a water column of at least 3,000 mm. 5,000 mm and more are only necessary for the far north or in rainy corners. More? You read that right because you will also find tents with 10,000 mm WS. But if you’re not going on an expedition to the North or South Pole, you don’t need such a high value. With 3,000 mm WS, you are flexible and safe.

By the way, everything from 1,300 mm is considered waterproof. That explains the mentioned minimum value of 1,500 mm, with which the manufacturers can praise their tents as “absolutely waterproof”. Unfortunately, Mother Nature has never heard of it. As always, practice and theory are two worlds.

Here are a few more numbers about the water column:

  • Umbrella: 800 mm
  • Rainwear class 3: 800 mm (EU standard EN 343: 2003)
  • Rainwear class 2: 1,300 mm (EU standard EN 343: 2003)
  • Waterproof tent fabric: 1,500 mm (DIN ISO 10966)
  • Waterproof tent floor: 2,000 mm (DIN ISO 10966)
  • Sitting & kneeling on a wet surface: 4,800 mm (EU Norm EN 343: 2003)
  • Clothing for sailors and mountaineers: 20,000 mm (EU standard EN 343: 2003)

Do you notice something? Keyword tent fabric and tent floor? Why is there a difference here? Quite simply: there is significantly more pressure on the tent floor. Because you lie, sit or kneel on it.

Therefore, the tent floor must have a higher water column than the tent fabric. Because when lying, sitting or kneeling, your body weight creates more pressure and therefore more stress. The demands on the tent floor are therefore higher than on the tent fabric.

Note: If a water column of 3,000 mm is considered a good value for the tent fabric, it is 5,000 mm for the tent floor.

Why all water columns are not same

In the end, the values ​​are rather relative. Why? First, there is no standard for measuring the water column. Europeans as well as Americans use completely different procedures.

Europeans – for example Bergans, Cocoon, Grand Canyon, Hilleberg, Jack Wolfskin – measure on brand new tents. The Americans – Big Agnes, Coleman, GoLite, Marmont, Mountain Hardware, MSR – on the other hand at five-year-old tents.

It’s logical that a five-year-old trekking tent had to take a lot. The material is subject to aging, plus the influences of the environment, weather and use.

Consequence: The value of a five-year-old product cannot keep up with that of new goods. Accordingly, a water column of 3,000 mm according to the US value is significantly better than according to the Euro standard.

But the comparison lags, because of the US standards, even well-known manufacturers such as MSR often only have a low water column. The MSR Hubba NX * or the MSR Elixir II * only measures 1,200 mm or 1,500 mm for the tent fabric and 3,000 mm for the tent floor.

That sounds bad at first. But curious: The Hubba and the Elixir are not cheap tents. At around 385 and 250 dollars, the prices are in the middle price range.

Manufacturers from Europe on the other hand “effortlessly” achieve a water column of 3,000 to 5,000 mm for their tent fabric. Because of the completely different tests and uses, the European tents are by no means of higher quality than US products.

Note: A higher water column is not always better. Instead, the value – depending on the manufacturer’s country – can even be confusing because different tests are used.

Why the water column is only one criterion

The weak points in the “tightness” of a tent are elsewhere. Namely, with the seams and the zippers, a water column of 10,000 mm is of no use if the seams, corners and zippers are not well made. Quality counts here. Because if the seams are bad, water will get into the tent. Consequence: you get wet.

Even the seams are just one criterion that disregards the water column. Therefore, in addition to the value for the water column, pay attention to:

The workmanship of the seams and zippers

If these are poorly made, the ingress of water is not a miracle – it is the logical consequence. Accordingly, seams must be taped and treated well.

Material of the inner and outer tents as well as the floor

Modern trekking or camping tents are made of polyester, nylon or ripstop nylon or cotton or polycotton (mixed fabric). Polyester is tear and abrasion-resistant, cheap and also very waterproof. For this, polyester is a bad choice in summer because synthetic fiber creates a lousy indoor climate.

The UV protection is also not good. Nylon on the other hand offers you good UV protection. It is also ultra-light but stretches when wet.

That being said, nylon trekking tents are expensive. Cotton convinces with the best room climate and UV protection as well as tear resistance. But cotton is heavy, dries slowly when wet, and is expensive.

Type of coating or impregnation

Finally, for the coating, either polyurethane (PU) or silicone (SI) is used here. PU is cheap and allows seams to be glued. However, it is heavier and worse in terms of UV protection. SI is light, very tear-resistant and UV-resistant. SI is more expensive and also does not allow seams to be glued.

Why cotton tents don’t have “WS”

In any case, the water column says nothing about these three points. Nevertheless, these criteria are essential for the tightness of a tent.

If you want to buy a new trekking or camping tent, don’t just look at the WS. The material is an interesting point. Tents made of cotton are not coated at all, but (if at all) impregnated. Because cotton swells when wet and thus becomes waterproof or impermeable by itself.

Caution: This does not apply to tents made of a cotton blend or polycotton or technical cotton. These must be very well coated. Otherwise, such a tent would not be waterproof. Cotton or cotton blends are more likely to be used in larger family tents than in trekking tents for one or two people. Because cotton is quite heavy, a modern hiking tent should be as light as possible.

In conclusion, the water column is only one point on the subject of water resistance. So don’t let yourself be blinded by a (high) WS. Rather, look at the workmanship or quality, material and coating. You are only safe from water ingress if all the other criteria are met. So carefully weigh the pros and cons when buying a tent.

If you travel a lot with a tent, a “double purchase” is even worthwhile. A tent for dry areas with a better indoor climate and one for wet areas that “hold tight”.

Note: How waterproof a tent is not just determined by the water column. Rather, the density of your new trekking tent is determined by the four criteria mentioned:

  1. Water column
  2. Workmanship & quality
  3. material
  4. Coating

How you can maintain the water column in your tent

There are a number of things you can do to keep your tent waterproof. The magic word here is tent maintenance. The better you take care of your trekking or camping tent, the longer it will last.

How can you take care of your tent? So….

  • Clean your tent after every tour, if possible already on the tour. You should remove dirt, sand and stones every day. If you pack your tent “dirty”, the coating will otherwise quickly sand off. Suddenly the tent is no longer airtight. So always shake it out well in the morning.
  • Pay attention to the subsurface when setting up. “Clean” it of sharp stones, pine cones, thorns, etc. These could otherwise pierce the tent floor and make it leak.
  • Tip: Use a tent pad (footprint). This protects the tent floor and, secondly, increases the WS.
  • Check the seams, as these are generally the weak point in a tent. You can treat leaky seams with seam sealer. This is especially necessary for tents with an SI coating, where no seam gluing is possible.
  • It is best to patch holes promptly. With a PU coating, the tape is sufficient. With SI, a patch is necessary.
  • Brace your tent well. Even if your tent is free standing, you should guy out in the wind. So there is less tension on the tent, that’s already the seams. However, do not use force to tension the lines. Seams and attachment points can tear.
  • Be careful with nylon tents: Here you may have to re-tension the guy ropes due to the wet stretch. And they relax when the tent dries.
  • Keep your tent dry. Never store it damp at home. On tour, you can dry the tent during breaks during the day.
  • Don’t cook in the tent. Firstly, there is a risk of fire, secondly, there are gases, and thirdly, condensation. From then on, heat damages the coating.
  • Also, sunscreen is a good idea, because the UV rays damage the material.

You can find more information about tent maintenance here!

How to pimp the water column in a tent

You can also pimp the tightness of your hiking or camping tent. As mentioned, a tent pad is especially advisable for the ground. This is a simple tarpaulin, also known as a footprint in “technical jargon”. With a tarpaulin like this, you will definitely increase the water column of your tent floor.

Important

When setting up the tent – first the underlay, then the tent – make sure that there is no water between the underlay and the tent.

Again: watch out for sharp stones and the like when setting up your tent. These can “perforate” your tent floor, allowing water to penetrate. A footprint serves here as additional protection.

Speaking of underground

Camping in a puddle is generally not a good idea. Better look for a small hill or a slightly sloping place where water cannot stand or run off.

You should also re-impregnate your tent after every major tour. This way, the rain rolls off better on the next trip, and the fabric doesn’t even become soaked with water.

Nice side effect: Your tent dries faster after a rain shower. In addition, a refreshed impregnation keeps dirt off better.

Test

You can use a “Watering Can” to check whether the impregnation of your tent is still intact. Put up your tent and empty “Watering Can” over it. If the water rolls off directly, everything is okay. However, if the water rolls off badly, you should re-impregnate your tent.

Conclusion: what you should pay attention

The water column is not everything when it comes to choosing a waterproof tent. On the contrary: If the trekking or camping tent is to be really “tight”, several factors play a role.

Whereby the water column in the tent is usually a little higher than stated by the manufacturer. Because the tent fabric arrives at the tent manufacturers almost “ready” on large rolls – including the coating. Because of the laying and kinking during processing, a certain part of the coating goes flat.

Nevertheless, the actual water column is usually a little higher than officially stated. Quasi for safety.

Finally, a few more tips. Pay special attention to your new trekking tent:

  • The floor, a high water column is important here: Since the tent floor is usually made of polyurethane, this is rarely a problem. If necessary, improve with a tent pad.
  • Well processed and taped seams if possible: These are considered to be the number one “water problem”. A tube of seam sealer in your backpack is therefore always a good idea. Especially for tents with a silicone coating.
  • Small holes at the seams: You should close this with a seam sealer. Otherwise, water will quickly get into the tent. Therefore, always set up a new tent at home first and check it out thoroughly.

If you are traveling in a “rainy region”, of course, it doesn’t hurt if you spend a little more money on your tent. Here you are even spoiled for choice: expensive and light or cheap and a little heavier.

In practice, both options can be waterproof. Expensive products use better materials like nylon, which makes the tent wonderfully light. A boon for your back, joints and muscles on longer tours. Cheaper products on the other hand rely on a “thick” coating, which of course means weight.

Get to your destination dry!

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