[darreninthenet]

Just to reiterate what's already been said - don't use tap water. We have a carnivorous plant expert/dealer local to us and he just collects and uses rainwater, as he says tap water will kill them.

Simple waterbutt attached to the drain pipe off the guttering and you get infinite free water for them

[dfc]

Water butt (noun) - British: a large container for collecting or storing a liquid (such as rainwater)

This is so much better than "rain barrel".

[alecst]

Was told the same thing, but my tap water works fine. If it’s true that it’s harmful I’d like to see some science (even citizen science.) Pretty sure it’s a myth.

[spiorf]

It's water that builds up limescale that it's harmful for the carnivorous plants. The peat moss substrate that carnivorous plants like is acidic and the limescale neutralizes that.

[alecst]

Plausible, perhaps -- is there any evidence?

[Xss3]

Yes there is plenty of evidence that carnivorous plants die in alkaline or neutral soil conditions.

Read literally any book about caring for them. They like acidic soil. Rain water is slightly acidic.

It might take a year or more to kill a plant by slowly draining its soil of acidity. Just like it can take a year to kill a big plant via inadequate lighting.

[diggan]

Probably depends on the location. I've had a bunch of carnivorous plants in Spain, not exactly great tap water, and killed a bunch of them before switching to purchased distilled water.

[teaearlgraycold]

Depends on your tap water. Hetch Hetchy water has worked perfectly for me for years.