Rainwater from the cistern also for laundry and toilet flushing?

So I refill a bit of salt 1 to 2 times a year. No effort, low cost.

Thank you for the answers.

The financial aspect should of course be taken into account somewhere so that there is no significant loss here. Since we have rather hard, calcareous water in our area, limescale will also accumulate here. Therefore, I am actually quite relaxed about the deposits with the water from the cistern.

The pipe for, for example, the toilet and washing machine does not have to be installed twice, right? I think this can be managed with a switching valve in a central unit.

Of course, it is not known how long 15k liters will last. But in summer it should be sufficient for the garden and in winter possibly for laundry.

The line for, for example, the toilet and washing machine does not have to be laid twice, does it? Here, I think you can use a switching valve in a central unit.

No, two lines. Garden water and drinking water must never be in the same line.

Is that really so? That no rainwater should get into the pipes of faucets, showers, bathtubs makes sense to me. But if I can introduce fresh water - in case of rain shortage - into the cistern that only supplies toilets, garden irrigation, and possibly the washing machine, that doesn't cause any problems. Rainwater doesn't get into the fresh water line - how would it? Am I wrong? It's the same for us. When the cistern is empty, I fill it up with fresh water. For the washing machine, I have a separate line to which I can connect the intake hose. Enlighten me. I'm just interested. Maybe I have a flaw in my thinking.

Am I wrong? It's the same with us.

Yes, you must NEVER use any other water in pipes intended for drinking water - whether from a well, cistern, or anywhere else. Two separate pipes are mandatory.

But if I can feed fresh water – in case of rain shortage – into the cistern, which only supplies toilets, garden irrigation, and possibly the washing machine, that should not cause any problems. No rainwater comes into the drinking water pipe – how should it?

That means you never have drinking water for the toilet? If so, water can mix – which is forbidden.
How is it regulated from the main connection so that water from the different pipes cannot mix?

For the washing machine, I have an extra pipe to which I can connect the suction hose.

An extra pipe from the cistern? That's how it should be.

No, we don’t have a fresh water line for the toilets and urinals. Everything is supplied by the cistern. I just have to refill it with fresh water when it’s empty. It doesn’t work the other way around here, which makes sense and I understand. No one really drinks from the toilet. Drinking water is only available at the other connections. Showers, bathtubs, bidet, sinks, and the kitchen faucet. I can’t use rainwater there – even if I wanted to – and of course I don’t want to.