What Is Polyester?
Polyester is a man-made fabric produced with fibers made from oil, such as polyethylene terephthalate (PET). It is low maintenance, light weight and wrinkle resistant as well as fast drying making it ideal for everyday use or in technical clothing.
Common polyester products include:
- Jackets and sportswear
- Rainwear and outerwear
- Backpacks and luggage
- Upholstery and curtains
- Gear such as tents and tarps for outdoor use
Is Polyester Naturally Waterproof?
Is Polyester Waterproof? No, polyester is not water resistant by nature. But it is a hydrophobic one — it does not readily absorb water.
What this means in practice:
- Polyester also has the added benefit of not absorbing moisture.
- Polyester dries far quicker than your average natural fibre, such as cotton
- The long rain will after all let water through
So, yes, while polyester can withstand a light rain or some water splashes, it obviously won’t completely repel water on its own.
Polyester vs Waterproof: Key Difference
It’s also helpful to know the distinction between water-resistant and waterproof:
- Water-repellent: Can resist water to some degree (polyester would fall under this category)
- Water proof: Total barrier to water, even under pressure
Polyester, left untreated, is water resistant and not waterproof.
How Polyester Becomes Waterproof
Polyester can be waterproof depending on its particular make-up of fibers and outer coatings. Which is why so many rain jackets and other outdoor gear are based on polyester.
Common Waterproof Treatments:
- PU (Polyurethane) Coating A thin polyurethane layer is added in the fabric which prevents water from seeping through. This is commonly used in: Rain jackets Tents Backpacks
- PVC Coating A heavier weight, more durable coating that delivers powerful watereproofing used frequently in: Tarps Industrial covers Waterproof bags
- DWR (Durable Water Repellent) Finish This treatment encourages water to bead on the surface, which increases resistance but does not provide for full waterproofing.
- Lamination (Waterproof Membranes) High-tech outdoor clothes could have laminated membranes that render polyester completely waterproof but still breathable.
Is Polyester Waterproof in Clothing?
Everyday Polyester Clothing
- Not waterproof
- Can resist light moisture
- Dries quickly
Polyester Rain Jackets
- Yes with treatment or coating
- Watch for phrases like “PU-coated,” “waterproof rated” or “sealed seams.”
Polyester rainwear will leak in the heaviest downpour if they are not coated or sealed.
Is Polyester Waterproof for Bags or Backpacks?
Polyester is a popular fabric that you find in many backpacks simply because:
- Strong
- Lightweight
- Abrasion-resistant
However:
- Normal polyester bags do not accept full water-proof.
- Seams and zippers can also leak water.
- Waterproof editions feature treated coatings or liners instead
For maximum protection, search for those with coated polyester or a waterproof liner.
Polyester vs Other Fabrics
Polyester vs Cotton
- Polyester is more resistant to water than cotton
- Water absorption and quick drying of cotton
Polyester vs Nylon
- Nylon is usually the more water resistant and durable one
- Polyester is better colorfast and resists rot and decay won’t fade.
Both materials must be treated to become truly waterproof.
Benefits of Polyester When Wet
Polyester, even when water resistant but not waterproof, has some advantages:
- Quick-drying
- Lightweight when wet
- Resists mold and mildew
- Maintains shape and strength
- Affordable and widely available
These features make it perfect as a sports and outdoor towel.
Disadvantages of Polyester in Rain
- Not fully waterproof without treatment
- Seams may leak
- Coatings will abrade over time
- Less breathable when heavily coated
How to Know if Polyester Is Waterproof
Check product details for:
- “Waterproof” or “water-resistant” labels
- PU or PVC coating information
- Waterproof ratings (measured in mm)
- Seam-sealed construction
If none of these terms are used the polyester is probably only water resistant.
Frequently Asked Questions (FAQ)
Is 100% polyester waterproof?
100% polyester is water resistant not water proof unless coated.
Is polyester good for rain?
Only in light rain. 8 UNTREATED POLYESTER Multimedia Heavy or long-lasting rain will seep through untreated polyester.
Are polyester rain jackets good?
Yes—when coated or laminated. Most waterproof jackets are made from polyester as the base fabric.
Does polyester absorb water?
Very little. Polyester is made of fibers that are squeezed very close together, making the fabric resistant to water and able to dry quickly.
Is polyester better than cotton rain?
Yes. Polyester is far superior to cotton in wet conditions.
Conclusion
Polyester isn’t waterproof but is both water resistant and quick drying, which makes it an ideal choice of base material for anything built to take on the elements. When it is treated with coatings or membranes, polyester can be made fully waterproof, which is why you’ll find it in rain jackets, tents and backpacks.
If the promise of waterproofing is what you need most, then when shopping for a jacket make sure to look for coatings and linings and seam sealing—not just the material.
