If you tour in Australia, be careful about using standalone taps/spigots. There is an increasing trend to pipe separately treated sewage which is clear water, but which isn't potable water fit for human consumption, to irrigate lawns in parks. Keep a watch for signs that say "Not Suitable for Drinking". The water also has a distinct odour.

In other places, the ability to treat water is limited, and after heavy rainfall, there may be deficiencies in the "health" of water coming out of taps. The East Coast of Tasmania falls into this category. There are usually signs or notices erected around town warning of this.

Often in Australia in remote areas, there are tanks that hold rainwater (the Nullarbor Plain is an example, as well as ocean-side pull-off areas). For public liability protection, these usually carry signs that say "Not Suitable for Drinking", but they may be OK, especially if it has been a rainy season. Sometimes these tanks are replenished by road tankers.

I think iodine was the old standby bug-killer, and if I was riding through suspect areas, I probably would take a small bottle of bleach as a steriliser... a squirt or two in a bottle and let stand for an hour to let the chlorine permeate out. Or I can just boil the water for five minutes and forget the bleach.

I carried a water purifier with me for ages, but never used it and I don't remember what happened to it. I have used two-llitre wine cask bladders in the past to stock up on water when going to a remote site; they're easy to pack down to almost nothing when not in use. I'd probably use a platypus bladder or similar now because the filler is larger.