The quality of the water depends on area, Perths water (like most of our cities) has Cl and a few have F, or various salts.
The severity varies from town to town, for example in Ingham QLD the tap water of the town is ok for carns providing one repots now and then, yet in Townsville a mere 100km down the rd the water will kill a dionaea or drosera within a week, even within Townsville (its a city) certain water in a few suburbs is fine for nepenthes, yet 10km away in another suburb it can be lethal.
I keep most of my plants at dads, near ingham, but he has a bore and lives in the mountains so the water is very "soft" as opposed to a cities "hard" water.
So you will have to check your own water, otherwise go to a clean creek (not one in a paddock as sheep and cattle pollute the water to much) or collect rain water.