In Adelaide (where the Water is no where as good as Melbourne), I use a twin filter under sink unit, with its own outlet. It was the cheapest unit I could find in Bunnings, but with decent filters inside. I use this water for all chemical mixing, but for final negative rinsing I use demin water. For print washing, I use the tap water and have never had an issue.
Originally Posted by bluedog
The main downside with these under sink units is the flow is not overly quick. You can buy (I used to have a friend who installed them) big units that you can install on the mains that will filter the whole house. This will only see a marginal drop in flow, but for Melbourne, I would suggest that this would be overkill