I use the Katydyn Combi and a SteriPen, with a bandana prefilter if the water is full of debris. So far, so good.

One of the concerns I always have is keeping the raw water part of the system, which is contact with what may be problem water, away from the clean water part of the system. If the raw water has giardia or whatever, then I do not want to have it come in contact with the rest of the filter setup.

So far I am relying on a separate freezer bag storage for the intake / raw water side, and then I immediately clean my hands with waterless sanitizer. I also use the sanitizer after attaching the intake / raw water intake tube to the rest of the system and before pumping. I do not touch the intake tube once it is attached until I am ready to remove it from the pump / filter.

Is this good enough? Are there some other best practices?

Thanks.