This One Maintenance Tip Will Keep Your Water Filter Lasting For Years

A way to procure clean drinking water is one of the most important items in a backpacker’s kit. And while there are various methods for doing so, filters remain the most popular, as they are lightweight, affordable, and work almost instantly to treat water from any natural source. But most hikers know that over time, a filter’s flow rate will decrease, or it may clog altogether. If maintained properly, however, a water filter can last for year and years. The easiest, most effective process to keep your water filter functioning properly is regular backflushing. Here’s an overview of how to backflush your water filter and keep it flowing smoothly hike after hike.

Transcript

When it comes to treating water in the backcountry, we have a lot of options for how to do it today. We can go for chemical solutions like chlorine or iodine. We can also use UV light to disinfect it, but the most common solution on trails nowadays by far are hollow fiber filters. You see these in all sorts of different forms. For most backpackers, the most common ones are going to be squeeze-style compact filters like the Sawyer Squeeze or like the filter I have here, which is the Platypus QuickDraw. These are really light, really easy to use, and they filter out the vast, vast majority of pathogens. But they do have a downside, which is unlike chemical solutions and unlike UV light, they can clog.

So today we’re going to go over an essential skill for how to maintain your filter, and that is backflushing.

To understand why filters clog, it’s important to understand how they work. So in its simplest form, a filter is basically a bunch of really, really tiny straws. And when I say tiny, I mean tiny. We’re talking 1 to 2 microns. That is a fraction the width of a human red blood cell. When you force water through these straws in a hollow fiber filter, they let the water through, but don’t allow any of the contaminants through. The result is clean, drinkable water you can depend on.

Over time, mud, silt, and dirt can get stuck in these fibers and reduce the flow of your filter, or even stop it entirely. At this point, backflushing is the best way to deal with it.

Think of a milkshake. If you’ve ever been drinking a milkshake and gotten a piece of cookie dough or a chocolate chip stuck in the straw, you know it’s a lot easier to blow out to dislodge it than to try and suck it all the way through. That’s basically what backflushing is. You take the filter and you run clean water through the clean end and out the dirty end to force those contaminants out.

So before we get to how to backflush, it’s worth talking about how to prevent your filter from clogging in the first place. There are some things you can do because it’s a lot easier to prevent this than to maintain your filter.

First of all, be careful with your water source selection. If you’ve ever been on a big high-flow river, you know there’s a lot of silt in it. That’s why on a lot of river trips or a lot of trails that follow rivers, it’s smart to pick tributaries and little streams that might run a little more clear, that way you’re putting less stress on your filter.

The same goes for backpacking in the mountains. If you’ve ever seen a really beautiful, brilliant turquoise mountain lake, especially in a glaciated area, that color is caused by rock flour, which is really, really finely powdered rock, suspended in the water. You run that through your filter, you will break it in no time.

Sometimes though, you might not have a choice of what water source to use. That can be the case in the desert. Last time I was in Canyonlands, the only sources I had available were these muddy, silty puddles. It was either that or nothing.

In cases like these, it can be smart to pre-filter. That’s basically when you just run the water through a bandana or other cloth to take out larger particles of dirt and silt. However, that can be really time-consuming.

So this is where backflushing comes in. How specifically you backflush your filter, or even if you can—because you can’t backflush all filters—comes down to what model you have. Make sure to read your filter’s instructions; that will give you some helpful tips.

The equipment you need varies. If you’ve ever bought a Sawyer Squeeze, you know that frequently they come with those big oversized syringes that you use to clean them out. If you have a Squeeze, that’s the best thing to use.

What I have here is this Platypus QuickDraw, like I mentioned. It actually flushes with a normal narrow-mouth plastic bottle. If you are using a Smartwater bottle as your reservoir, that’s perfect for this. You can use that same bottle to backflush it. It’s only going to touch the clean end so you don’t have to worry about it getting contaminated.

I have a little bit of a Mountain Dew problem, so I have this empty Mountain Dew bottle that I have filled up from my kitchen sink. If you’re going to follow my instructions, pro tip: Do not forget to drink the Mountain Dew first. You could try and backflush your filter with Mountain Dew. I don’t think it’s gonna go very well.

So let’s head outside and give this a try.

OK, so I have here my plastic bottle and I have my filter. I’m just gonna pop both caps off of this filter. So we have the clean end and the dirty end. So I’m gonna open up my plastic bottle. And what I’m gonna do is I’m just gonna press the lip of this bottle to the drinking end. And you can see how tight the seal it forms is. There’s not really any water leaking out. This is specific to this model of filter. Again, I emphasize, check the instruction manual.

And I’m gonna give this bottle a little bit of a squeeze. And you can see the water flowing out the bottom. It’s flowing out without too much trouble. That’s because I already cleaned this filter once, but it could probably do with another backflush.

And what you see here is pretty much it. You’re just gonna squeeze through an entire bottle of water. It helps to probably do it twice. I usually would do about two of these. And you will have a nice, clean, and hopefully fast-flowing filter.

So after this is done, you’re gonna want to dry your filter out if you don’t plan on using it right away. It’s also a good idea, especially now as it’s getting cold in this part of the year, to keep your filter from freezing. If your filter freezes, it’s going to break. It may become dangerous if you use it or not work at all. So if the temperature is going to dip below freezing, make sure you keep this warm either in your jacket or in your sleeping bag with you.