Butput an inline filter between a hydration bladder and yourself? I'm not convinced anything like that will work, even if you could put such a system together. The reason: You need to have some kind of pumping action to push the water through the filter. In the SafeWater system or Exstream bottle, that comes from a combination of sucking on the bottle and squeezing it. Trying to pull water through a hose AND a filter with suction alone isn't going to be possible. You'll be hiking or biking around with your cheeks caved in.
What to do? Pump filters are the obvious solution, but you must have your reasons for not wanting to go down that road (weight, perhaps). That leaves you with chemical purifiers, such as Potable Aqua ($8 for 50 tablets plus taste neutralizer; www.rei.com). That stuff kills just about anything.
More water-filtering advice and product reviews can be found in Outside's 2004 Buyer's Guide
Support Outside Online
Our mission to inspire readers to get outside has never been more critical. In recent years, Outside Online has reported on groundbreaking research linking time in nature to improved mental and physical health, and we’ve kept you informed about the unprecedented threats to America’s public lands. Our rigorous coverage helps spark important debates about wellness and travel and adventure, and it provides readers an accessible gateway to new outdoor passions. Time outside is essential—and we can help you make the most of it. Making a financial contribution to Outside Online only takes a few minutes and will ensure we can continue supplying the trailblazing, informative journalism that readers like you depend on. We hope you’ll support us. Thank you.