Are Drawstring Bags Waterproof?
Drawstring bags are more practical than backpacks when carrying around those essential items that don’t fit in your pockets, such as the water bottle, sunscreen, snacks, slippers, change of clothes, deodorant, meds, notebook, phone, or wallet. Drawstring bags make excellent bags for beach goers, music festival attendees, cyclists, hiking enthusiasts, and fitness buffs. But since there are outdoors activities that require these bags to be waterproof, some of our readers have been wondering whether drawstring bags are waterproof.
Before we answer that question, we need to clarify the difference between the bags that are waterproof, those that are water repellent, and their counterparts that are just water resistant. Because there’s a huge difference, and both buyers and manufacturers often wrongly use the terms interchangeably.
Waterproof vs Water Repellent vs Water Resistant
Waterproof
A waterproof bag or fabric is 100% hydrophobic, which means that it will repel water and not let any of it pool or wick. On a waterproof fabric, water just forms beads, which need a pressure of more than 10,000 mm (or slightly over 14 psi) to be pushed through the fabric. A waterproof drawstring bag will not allow any spills to leak out and will keep your belongings bone dry even in heavy downpours.
Waterproof gear is usually much more expensive than the water-repellent or water-resistant one as the technology and materials used in its creation is more advanced. A genuine waterproof fabric can be washed countless of times without the "waterproofness" wearing off, unlike water-repellent fabrics.
Quality waterproof gear, including waterproof bags, clothing, and tents usually come with sealed/ heated seams and waterproof zippers (if any) – as these are the areas that allow most of the water in. Also, waterproof gear may be made out of multiple layers including an extra waterproof membrane to ensure that absolutely no moisture gets in.
Keep in mind that all these neat features involve higher production costs than water-resistant or water-repellent products, so don’t take a manufacturer’s word for it if they claim that a fairly inexpensive product is “waterproof”. Most likely, that product is either “water-repellent” or (in the worst case) just “water-resistant.”
Water-Repellent
A water repellent bag or fabric has been treated with a special surface coating known as Durable Water Repellent (DWR) in order not to be easily permeated by water. Just like waterproof fabrics, water-repellent ones do not allow water to pool or wick (you’ll notice water beads on the surface), but unlike genuine waterproof materials, water-repellent ones may lose water repellency in time, especially through wear and tear and repeated washes.
Water-repellent fabrics need to be waterproofed with a quality DWR (waterproofing spray or seam sealer or both) every now and then. The water pressure a water-repellent fabric can withstand before water gets through is around 1,500 mm (or around 2 psi).
Water-Resistant
Water-resistant fabrics are those tightly woven fabrics, especially man-made such as nylon and polyester. These fabrics are naturally water-resistant because water needs some time to leak through the fabric. A water-resistant fabric holds out against light showers, light snowfall, and morning mist, but if exposed to a high-humidity long enough it will get damp. Water-resistant fabrics can be made water-repellent by treating them with a quality DWR.
Are Drawstring Bags Waterproof?
The short answer is ‘no’. Drawstring bags are usually made of either man-made materials such as polyester, polypropylene, and vinyl or natural fabrics such as cotton/canvas or jute. Untreated natural fabrics are very water absorbent so we’re not even talking about water-resistance here.
Man-made fabrics such a polyester tend to be naturally tightly woven, a feature that increases the time water needs to permeate the fabrics’ threads. If the polyester is thick enough you might notice water beading on its surface, which means that the fabric is water resistant. So, the long answer to our question on whether drawstring bags are waterproof is “No, but they are water resistant to various degrees depending on the material they are made of.”
So, if a polyester drawstring bag is marketed as “waterproof”, don’t believe it. The manufacturer likely refers to the fabrics’ natural water resistance or the fact that the fabric has been treated to become “water-repellent” with a DWR. A genuine waterproof bag would involve multiple layers, seam sealing technology, ad a hefty price to be labeled as such.
If you plan on taking your drawstring bag on a kayaking or paddleboarding adventure we recommend placing it in a quality dry back which has at least an IPX 4 rating and it is made of high density material. An IPX 4 rating means that the bag is not designed to be fully submerged, but it repels water much better than water-resistant fabrics.
Can You Waterproof A Drawstring Bag?
Yes, you can add a waterproof coating to a drawstring bag, regardless of fabric used. For cotton/ canvas, we have posted a full guide to waterproofing cotton/canvas in the comfort of your own home here. For nylon/ polyester bags, do not try the wax method shown in our guide. This classic method works best on cotton canvas and leather but can create a mess on man-made fabrics.
Cotton drawstring bags need to be waterproofed ASAP because of cotton’s hydrophilic nature, which means that it attracts water molecules to its fibers like there’s no tomorrow. Untreated cotton can wick away up to nearly 30 times its weight in water. This may explain why cotton gets so easily imbued with water and takes so much time to dry out. Click here for Tote Bag Factory’s exclusive selection of cotton and canvas drawstring bags.
On nylon, vinyl and polyester, use a good waterproofing spray and follow the instructions on the package to a Tee. Just make sure that you apply the spray in a well-ventilated area because waterproofing products usually come loaded with toxic fumes. If you apply the method outdoors seek a sheltered area as the wind might stick dust and grit to your bag, compromising your mission to make it 100% water-tight it. If the manufacturer instructs you to apply a double layer of the spray do so.
To Wrap It Up
Are drawstring bags waterproof? No, they aren’t. Those in man-made fabrics are often water- or weather-resistant instead of waterproof. True waterproof fabrics require technologies and costly manufacturing methods which are ultimately reflected in the final retail price. So, don’t expect low- or medium-priced drawstring bags to be genuinely waterproof even if it says so on the label. Shop wisely!