Here is a piece of kit I will always have with me,whether riding,hiking or camping. I bought this bottle out of necessity after a 60 mile round trip rail to trail ride. The map for Van Fleet trail showed two water stations so I figured I would pack lite and only take two h2o bottles and refill at the stations. Wrong!
At the 30 mile end point there was a fountain, I turned it on and let it run took a swig and spit it out. Water was hot,cloudy, foul smelling and tasted like iron. I swallowed some and my stomach immediately protested. I wasn't going to risk it. SO I rode with 12 oz of water for 18 miles and came upon the other station. This one was a little better but I only took a quick gulp. The last 12 miles to the car were brutal. I'm in Florida and it's 92 degreeish riding hot pavement little to no shade and thirsty.
When I got home I researched water bottle filters and discovered this reasonably priced excellent filter system. http://www.berkeyfilters.com/berkey-water-filters/sport-berkey.html I am amazed at the amount of impurities it can filter.
I bought mine on ebay for around $15shipped from the seller in Colorado. It fits in holders well and has a 640 refill capacity from municipal water or 160 from any source.

The filter is connected to a tube you drink from like a straw. Having a roll top cover the straw will stay clean in your bottle cage.
Drinking thru the straw is not as quick as say a Camelbak jet valve but this isn't my primary bottle. I won't leave home without it!
Thanks for looking,comments welcome.