How to waterproof your bag

Whether you've been out in light drizzle or a serious downpour you'll have soon realised that your backpack isn't waterproof. Though the material is water-resistant and some rain will just run off, coating the whole thing with Gore-Tex or similar would be hideously expensive. Rain gets into bags via a number of methods, either soaking through the fabric, entering through holes and zips, or getting in through contact with the ground when you put the bag down on wet grass.

Although there are waterproof bags out there, primarily designed for kayakers, they are heavier than walkers' bags, and do not have the ergonomic design to keep you comfortable for hours on the trail. With those aside, there are a few things you can do to waterproof the kit in your bag, keeping your spare clothes dry and your electronics in working order.

The most visual way of waterproofing a bag is by using a rain cover. These are large sheets of water-resistant material that are pulled over the whole bag on the outside and which have either an elastic rim or a draw-cord to hold them in place. Some bags even come with these in-built so they can be stashed in a separate hood pocket when not needed. Although they provide quick protection and are quite cheap, there are a few disadvantages.

Firstly, because they are only water resistant, water will get in eventually, and when it does, all your kit gets wet. But the bigger problem for me lies in how they catch the wind and flap around, generally being annoying and frequently coming off or acting like a sail pushing me sideways.

The other method for keeping kit dry is using dry-bags. These come in a number of different sizes, with enough room for a phone and wallet, all the way up to a change of clothes and your packed lunch. The key difference here is that dry-bags go inside your bag, and are excellent at separating your kit rather than having everything shoved in as you packed it; this makes finding things more efficient when you're out and about. A good tip would be to get a set of different sizes and different colours, and then to separate your kit into the bags depending on how often you use it. For example, I have a dry bag with hat, gloves, buff and sunglasses in – items that will probably be used during the day and which can stay together near the top in their own bag.

Dry-bags work well as deflecting rain water, but water can still get in, especially if the bag isn't done up properly or if they are submerged in a puddle at the bottom of the bag. For the extra step in keeping your vital kit dry like phone and GPS, consider an Aquapac case, which I have had out in terrible weather and which has still kept my phone dry.

There's nothing wrong of course in combining the methods, so having your kit in dry-bags in your backpack, and then having a rain cover on the outside. The message we're trying to get across here is that your backpack itself isn't waterproof, so some thought needs to be given on making sure everything still stays dry.