If you’ve slept in a good tent in a rainstorm, you’ve likely experienced the wonder that it is to have rain pouring down on your tent without getting wet. It might be easy to think that because most tents made out of vinyl are made of the same materials, they should all be waterproof, but is that the case?
Although the fabric of a tent is not waterproof by itself–a tent can keep you dry during a storm if your tarp (for double-walled tents) is set up properly and the seam tape and hydrophobic coatings are in good condition.
Doing research for this makes me realize how much goes into weatherproofing a tent! There are a lot of factors that impact the water resistance of a tent, and so good research is required to find a tent that will keep you dry.
By the way, as an Amazon Associate, I earn when buying qualified products through links on my site.
Are Tents Waterproof?
Tents are not waterproof–even really good tents will let in water after enough rain. If you carefully set up your tent you can mitigate this. But really, tents are designed to be clever redirectors of water (very similar to the house you live in). If your tent is not set up properly or if you have water pooling in any way, your tent will let water in.
This is actually a complicated question–here’s a table to explain what parts of a tent are waterproof/water-resistant:
|Part of Modern Synthetic Tent
|Water Resistance Level
|High: Water will bead off but water can still drip through if water pools
|Medium: The tent fabric is more breathable than the tarp, but water can still bead off a little bit, but eventually the tent fabric will absorb the water
|Low to High depending on treatment: Seams are not waterproof and have to be treated with seam tape and/or hydrophobic coatings
|Medium To High: The floor of the tent can be “tarp-like” Depending on if you have a bathtub floor or not. Water can soak in or condense after extended exposure.
|Low to Medium: The common mesh walls that you see in double-walled tents can actually be waterproof-treated. Water will bead off or absorb into the mesh, but water will start leaking through pretty quickly with lots of exposure to rain.
Even the parts of the tent that are highly water-resistant will eventually let water through if continuously exposed–especially if you’ve used your tent for a while and the waterproof coatings start to erode. Read here later in this article for more details on what waterproof coatings are used.
How Do I Keep Water From Coming Into My Tent?
The process of keeping water out of your tent is actually pretty simple to explain but it can be difficult to do in real life. Sometimes there is no good spot to put up your tent or maybe you don’t have enough rope to stretch out your guylines. If you follow these steps then you should stay dry even during a decent storm:
Buy A Tent With A HH Rating Greater Than 1000
It may already be too late to go buy a new tent–but generally, the higher the HH level (read here in this article to see what that is) is going to be more water-resistant.
Pitch Your Tent On a Slope Without Water Runoff
To keep the bottom of your tent dry, you should pitch your tent on a slight slope so that water won’t pool.
If you pitch your tent on a completely flat piece of ground (this is kind of rare in and of itself), then water will pool and you’ll get wet.
If you pitch your tent in a dip (where the tent is at the lowest point of slopes on two sides of the tent), then water will pool and you’ll get wet.
If you pitch your tent where water runs off (in a channel of some sort), then you’ll get wet.
Stretch Out All Your Anchor Points
Whatever type of tent you have, you need to stretch out the tent at all anchor points by tying guylines (or using provided guylines) outward. Let me show you:
In the case of this picture, this is just a tarp corner, but if you look at your tent chances are you’ll see loops that are designed to be anchor points so you can tie the tarp to tent stakes that you put in the ground.
Why? Two reasons:
- Stretching out the tent fabric will prevent the fabric from making folds where water can pool
- Stretching out the tent fabric is essential for ventilation (often these anchor points are where the tent vents are). Ventilation is as important for staying dry as a tarp is
Sometimes your tent will have pre-attached bungees or cords that are meant to stretch out the tent to provide ventilation and stretch out the tent fabric, such as this picture here:
Ventilate, Ventilate, Ventilate
There are two ways you can get wet from a storm in your tent:
Generally, we don’t think about tent condensation as much, but believe you me, if you don’t take care of condensation then… you’ll get wet.
Stretching out your tent with guylines as I talk about above is crucial to provide ventilation. After that, there’s not too much you can do–although you can open windows (sometimes tents have windows that have mesh so you can let light/air in). You’ll have to balance the risk of water splashing into the mesh and getting your tent wet vs. condensation.
It’s not a bad idea to use a towel (we love our travel microfiber towels similar to these ones on Amazon for this purpose) as a way to wipe up any condensation that happens in the tent.
Tape Your Seams (Or Seal Them)
If you look carefully at the seams inside your tent, you’ll notice there is what appears to be tape covering the seams. This is seam tape and it DOES wear out over time. At the time of this writing, I actually have to go fix this in our tent, soon.
If you’d like to see what gear you can buy, I talk about how to waterproof your own tent later on in this article.
Coat Your Tent
Tents are made more waterproof because of their coating. I talk about what types of coatings are used in tents in this part of the article, and you can learn to do your own tent coating here in this section.
Keep Your Stuff And Yourself Away From the Sides Of the Tent
Condensation is your enemy–and one easy way to let water in is actually by the sides of the tent themselves. If you can, make sure your gear, your clothes, your sleeping bag, and yourself are not touching the sides of the tent while you’re in the tent.
Because of physics, the sides of your tent will condense. If you’re touching the sides of your tent or your gear is, then water will find a path inside your tent. If you don’t touch the sides of your tent that will help keep the water on the path to the ground.
Lay a Tarp Under your Tent WITHOUT IT PEEKING OUT FROM UNDER THE TENT
An additional ground covering helps a lot–it protects the floor of your tent and is an additional layer against condensation and water build-up.
However, if your ground covering is peeking out from the sides of your tent then that means that water can drip onto the tarp and become trapped between the bottom of your tent and the tarp.
Make sure your ground covering is completely hidden underneath the tent.
You can see more pictures and detail in my article here on ground coverings.
How Do I Buy a Tent That’s Waterproof?
This is a difficult question to answer, as the technical specs don’t tell the whole story. Even a tent with good “specs” might not be very weather-resistant. The design of the tent as well as other attributes all play a part. Here are a couple of things to look for in any case:
Waterproof Rating, or HH
Tent fabrics have a waterproof rating. This rating called HH (or Hydrostatic Head), is expressed in millimeters (mm). The higher the mm, the better the waterproof rating.
If you are planning on significant rainy weather, then a HH rating at or higher than 1000mm will give you enough protection.
One attribute you should look for when trying to get a waterproof tent are “taped seams“. Taped seams just means a waterproof tape made of silicone or polyurethane is covering the seams. This doesn’t mean that the seams are taped well, though, so you might have to inspect to ensure there’s no peeling or other defect with the taped seams.
Some seam tapes seal to the seams with heat and will penetrate the holes thus creating a tight seal.
MSR tents advertise a stitching technology that uses precision stitches with waterproof thread that swells to seal the hole created by the needle.
This just means that the fabric is folded inside the tent, so the seams are sewed inside the tent rather than on the outside of the tent. This is just one technique out of many to try and not expose the seams to water.
4-season is definitely a marketing term and doesn’t necessarily mean anything. Many tent manufacturers use the term 4-season to mean a tent with higher weatherproof capabilities. Don’t count on this term to be what you need, as 4-season tents are often designed to withstand wind and to some extent cold, and not wet, so you have to look at the other capabilities of the tent to make a decision.
No Tent Is Waterproof–Eventually
A brand new premium tent with a thick layer of hydrophobic coating is going to be a champ at keeping out water–but tents are exposed to water, air, and sunlight, and eventually, those waterproof treatments will fade.
As far as your budget and my budget is concerned, there is no tent that is forever waterproof without additional treatments.
How are Nylon or Polyester Tents Waterproofed?
Just like in chocolate-dipped ice cream, the secret about waterproofing synthetic materials is all about the coating.
Tent fabrics, in order to be “waterproofed”, have to be coated with either polyurethane, silicone, or a DWR (Durable Water Repellant), or even a combination of several of these.
All of these coatings will erode over time, and so even a very expensive tent with all the waterproofing treatment will need re-treatment if you want to continue to benefit from a dry tent.
DWR is the most lightweight treatment of all of these sprays (and therefore will erode), Teflon being a recognizable type. The use of DWR is controversial as to its environmental impacts and its overall effectiveness.
Polyurethane is a plastic material which is commonly used for waterproofing fabrics (including tents). Typically the type of polyurethane are either polyester urethane (PU) or polyether urethane (PE), which have similar attributes with PE having some advantages of longevity and lack of water absorbency over PU.
Silicone is an inert substance known for its nonstick capabilities. It is incredibly water-resistant and lasts a long time.
Tents are coated with some form of polyurethane or silicone, and many times both.
If you want an explanation of the different waterproof coatings as well as a breakdown of advantages and disadvantages, look at this blog post from slingfin.com.
Are Nylon or Polyester Fabrics Waterproof?
Nylon and polyester fabrics (which tents are often made of) are not naturally water-resistant. However, nylon and polyester can be woven in such a way as to resist water since nylon and polyester don’t absorb water like cotton does.
If you have ever used nylons, or worn a polyester shirt, you probably have spilled water on them and left a big wet spot on your shirt that you had to carry around before they dried. (unless you’re one of those amazingly coordinated people who know how to drink water properly… I guess maybe I’m admitting too much here).
Polyester fibers don’t absorb water like nylon fibers do, but fabrics are just fibers woven close together, and water can seep or be pulled through to the other side of a fabric, polyester or nylon.
The weave of the polyester and nylon does impact how much water can get through, and denser fabrics will generally stop water better than thinner fabrics of the same type.
Even if your fabric has a very tight weave, water will still get through the seams. Two pieces of fabric are joined with seams, which means a needle and thread passes through the fabric, tying them together. Seams are an entry point for water.
Why Is it So Many Tents Leak?
As I was researching the process in how nylon and polyester tents are waterproofed, it turns out that adding the coating is a tricky and delicate process. As it is common for a tent to be coated with PU and with Silicone, the different types of coatings must be added separately as they are not compatible to be applied together. In fact, if too much silicone is added, the PU won’t adhere to the tent properly!
Coupled with that, sealing the tent seams is a tricky and tedious business, and if rushed or done offhandedly, the seams will inevitable allow water in.
Buying an inexpensive tent means you are at risk of buying a tent that doesn’t pass quality control standards, and you may get a tent with very poor waterproofing.
If you are in the market for a tent and want to see what the prices of a budget tent vs. a high quality tent, check out my tent prices guide where I compare tons of different tents so you can find which one works for your situation.
Which is Better for Rain? Polyester or Nylon?
This is somewhat of a holy war kind of topic where there is no right side and opinions abound!
However, one aspect of nylon that can’t be denied is that it does absorb a small amount of water. If a nylon rainfly gets wet, then the rainfly will sag slightly. Tentlabs did a pretty in-depth comparison here if you want to see examples of how much sag can happen.
Why is sag a big deal? Maybe it doesn’t look as nice, but does it cause any issues?
A huge part of the water-resistant capabilities of a tent is gravity.
The roofs of our houses are sloped in such a way to make rain run off. If water was allowed to collect on top of our roofs, then water would eventually make its way into our houses. This is true of tents. Tent walls are sloped downward, so the water takes the path of least resistance down to the earth.
Any bunching or folds in the tent means a stopping place for water. Any place on a tent where water collects is where water will soak through.
Polyester is superior in this point because it doesn’t absorb nearly as much water, and so after a long rainy night, the tent will still be as taut as it was when you set it up.
Are Cotton Tents Waterproof?
Cotton tents, more commonly known as canvas tents, are not as common, nowadays, but they are an old technology that’s been around for a long while.
Canvas tents do have a natural waterproofing ability, but it requires some preparation.
Cotton is a very breathable fabric, which is part of the reason of its huge popularity in textiles. You’d think that this would make it not-so-awesome in rainy weather.
Cotton, however, absorbs water like crazy, and will actually swell up when wet, sealing the pores of the tent, effectively creating a water-barrier. It’s the “can’t beat ’em, join ’em” kind of approach where the water itself is used as a way to redirect the water to the ground.
To make a canvas tent more waterproof, it needs a little bit of water to swell up the canvas fibers. You can do this yourself with a hose, and if you want you can put a smelly friend inside “to supervise” while you’re doing this so that they get a much needed bath.
A problem with this is that the walls of your canvas tent are swollen with water, which means that if you, or anything else you have touches the walls of the tent, capillary action will send the water into the tent.
Some canvas tents are blends of synthetic and cotton to get the best of both worlds, while others are completely made from polyester.
As always, there is a trade-off for each material.
How to Waterproof your Canvas Tent
Many different methods are out there to do your own waterproofing of canvas:
Some swear by applying a DWR (durable water resistant) spray to the canvas (make sure to avoid silicone as this will gum up the pores of the cotton canvas), on a yearly basis, but as I’ve mentioned, there is some controversy in this method.
Still others use wax, or linseed oil or other substances to create a waterproof barrier on a canvas tent. Be very careful about any of these methods, especially oil-based methods, as oil and canvas can create a gigantic fire-hazard. (even creating the potential for spontaneous combustion)
The absolute best and foolproof way to waterproof your canvas tent is to suspend a tarp over your tent. Admittingly this isn’t the easiest thing to do sometimes, but it is by far the most effective, and won’t impact the fire-retardant or breathable capabilities of your canvas tent.
If you’d like to see more details about why you possibly would want a canvas tent, I found several compelling reasons and put them in this article.
How to Waterproof Your Own Nylon/Polyester Tent
Before you embark on this journey, remember that it’s not the fabric that creates the waterproofing as much as the coating. Although polyurethane and/or silicone have decent longevity, if the the tent was stored wet (storing a wet tent can destroy a tent much more quickly. Check out my article on drying your tent to see how to dry your tent and why)
If the protective PU or silicon coating is peeling off the tent walls or rain-fly, then your tent is not salvageable, at least in terms of its waterproof abilities. You can always get a replacement fly–but if your tent floor loses its waterproof power, then you might want to start shopping around for a new tent.
Where you CAN waterproof your own tent is at the seams and by repairing small holes.
Tents can accumulate small holes over time (our tent right now has a couple in the tent floor), and these holes can let in water. Using patch kits matching the fabric of the tent can extend the life of your tent and keep water from coming in.
A very common way for a tent’s weatherproofing to deteriorate is at the seams. Even if they’ve been factory taped, heat-sealed, reinforced with adamantium (just kidding on the adamantium), these seams will eventually deteriorate. Fortunately, you can apply your own seam sealer or tape to keep water out and make your tent last longer.
Step 1: Find problem areas in your tent by hosing down the tent in your backyard and watching carefully for areas where the water is soaking through.
Step 2: Apply the seam sealer using a syringe or a brush applicator to the inside of the seams (inside the tent)
Step 3: Ensure no beads or drops form, wipe away with a sponge you won’t use again (you may have to use mineral spirits on the sponge to be able to work with the seam sealer)
Waterproof vs. Water-Resistance
I’ve used waterproof and water-resistance interchangeably in this article, but to ease my mind about being correct, I wanted to mention that no tent is waterproof. A waterproof tent would be a tent that you could submerge in a swimming pool and it wouldn’t allow water to pass through.
Tents are at best water-resistant. Getting this water resistance is really a combination of several different techniques which should all be explored if you’re wanting to stay dry.
Water Resistance vs. Air Breathability
Another conundrum to think about while researching a tent is that if your tent fabric is breathable, you will have less moisture build-up inside your tent. If your tent fabric is less breathable, it is likely more water-resistant.
It’s a trade-off! Even if your tent is super water-resistant, you may find water condensing on the inside of your tent from the air you breath and from general humidity.
I’ve experienced this many times. Even if it doesn’t rain, if it gets chilly outside, water will condense on the wall of the tent, making everything damp and clammy.
So what do you do?
Remember that to keep the inside of your tent dry, it’s just as important to ensure your tent has adequate ventilation. Guying out the vents on your tent and ensuring your rainfly is taut will make a big difference on the inside of your tent in the morning.