Construction costs are currently skyrocketing

The cistern will start to pay off when the garden water meters are abolished. It is much easier to implement than to control when someone turns on the sprinkler. Aside from the fact that it is pure madness to run extensively treated water of drinking water quality through the sprinkler.

That's the joke of the century anyway. You install heat pumps that only pay off after 15 years... Photovoltaics that could never pay off at the current moon prices. And that stuff has a lifespan of... 15 years? Maybe 20.

But with a cistern, which saves increasingly precious drinking water, many cubic meters every year... suddenly it has to pay off, and preferably already after 3 years?

A concrete cistern lasts... 40, 50 years?
The 3-4,000 EUR is very well-invested money.
Anyone who doesn't have a cistern should better not mention the words ecology, environmental protection, and climate change.
It takes an incredible amount of energy to turn wastewater into drinking water... just for the lawn?

That's anyway the joke of the century. You install heat pumps that only pay off after 15 years... Photovoltaics that could never pay off at the current moon prices. And that stuff has a lifespan of... 15 years? Maybe 20. But for a cistern that saves increasingly precious drinking water, many cubic meters every year... suddenly it has to pay off, preferably after 3 years? A concrete cistern lasts... 40, 50 years? The 3-4,000 EUR is very well invested money. Anyone who doesn't have a cistern should better not utter the words ecology, environmental protection, and climate change. It takes an incredible amount of energy to turn wastewater into drinking water... for the lawn?

There are many people who have legal wells. They don't use drinking water for watering. And then the cistern wouldn't pay off even in 100 years. The disadvantage of the cistern is that when you really need a lot of water, it doesn't provide much water. Before the rain this week, we had 6 or 7 weeks without rain. What would the cistern have helped me? How far do I get with the 5 or 6 m3? My domestic water system can deliver 6 m3/h, my well probably doesn't provide that much, but let's say only 1 m3, then the cistern is empty after 6 hours.

They simply subsidize everything, e.g. Intel with 10 billion, the electricity price or electric cars. Yes, I’m also happy when I get a mid five-figure sum gifted to me, but who paid for it? Yes, the taxpayers, and I certainly don’t need it.

Housing subsidies are a different matter for me, but here too only owners are favored. Tenants are left out.

I wouldn’t have thought so, but I totally agree with you. I reject this frenzy of subsidies and discounts. Here a fuel discount, there an electricity price cap (both could be fully exploited by the corporations), there a few hundred euros energy allowance. What good are 300 euros once, especially when they come way too late. Instead, we need cheap, sustainable energy etc. They should better focus on that instead of keeping people happy with tiny bites. What could have been built for them in wind turbines with the costs of these mini aid packages ... I would also completely cut the (new) housing subsidies. If at all, then promote refurbishment of existing buildings.

However, I find it just as problematic that masses of people from other countries are fully cared for here without ever having paid a cent, while locals are then told that they must first use up all their assets.

I understand what you mean, but I consider this view to be a misconception. With real estate, you are 1000 times wealthier than these people and also significantly better off. You have assets and can do with them as you please. Not selling them is also your own choice. Others do not have these assets, the associated freedoms, or many other freedoms. This only seems "better" at first glance.

Photovoltaics, which could never be worthwhile at the current moon prices. And that stuff has a lifespan of... 15 years? Maybe 20.

Experts currently speak of 30 years. Photovoltaics have proven to be energetically profitable in under 5 years.

A concrete cistern lasts... 40, 50 years? The 3-4,000 EUR is very well invested money.

Calculate for me how much money I can save with that. My estimates for a 3000€ cistern are about 50€/year. Unfortunately, that means it only "pays off" well after the 40-50 years. With cisterns, unfortunately, it is often like with photovoltaic storage. Always full when you don’t need it and always empty when you urgently need it. It becomes more sensible if you use it for the toilet and garden, but then you will never get by with 3000€.

It costs an incredible amount of energy to turn wastewater into drinking water... for the lawn?

Yes, how much energy does it take (in kWh) to produce one m³ of water? I’ll gladly help you with some numbers: If it is "just" pumped from the ground, it’s about one kWh. If it has to be produced by reverse osmosis, then 4-9 kWh. A well-dimensioned photovoltaic system easily produces that on the days when you need water for watering.