Kevin there are a number of in line water filters
you can attach directly to a water hose. I have seen them used a lot but I cant help you as to how well they work or dont.
I have a backpackers filter which I use when Kayaking but as has been mentioned they are very slow.
I normally start out my trip by freezing large water containers at home and use them in the cooler instead of ice blocks and then use them as drinking water. Once thats all used up some of the big grocery store chains have water stations where you can refill your own containers with water for a small fee.