Sydney is lucky enough to have a fine water supply. As long as the pipe fittings to one’s house are good (and they usually are) the water is free from harmful contaminants. Other places in the world are not so lucky, and some people need to filter the water they drink. There are several methods for doing this.
These can mount under the sink or come as a stand-alone pitcher. They filter most pollutants out of the water, and noticeable improve the taste. The filtration process takes time, so the household will be limited in the amount that can consume per day.
It is possible to have all water in the household filtered; residents can shower and brush their teeth with filtered water. But this is both expensive and unnecessary. If we are not ingesting fluoride there should be no issues.
These use a semipermeable membrane to filter anything larger than a water molecule. Often this is combined with carbon filtration. These devices can be mounted under a sink, and wile effective they tend to cost several hundred dollars.
This simply boils off steam that is then condensed in virtually pure water. Anything that boils at a lower temperature than water gets left out. Some people manage to distil water on stovetops; others buy specialized equipment.
Clean drinking water is obviously important for our health. We can be less particular about water used for cleaning or hydronic underfloor heating. As long as the cleaning and heat pipe fittings are not damaged by the water, which is highly unlikely, these cleaning and heating systems will operate without issue. DIY Hydronic heating should not require any apparatus to filter the water.