ᐅ Cistern! I don’t want one, but I am being forced to have it – experiences

Let me break down the calculations. The average person in Germany uses about 120 liters per day, with roughly 27% for toilet flushing and 12% for laundry. That adds up to around 40% or 48 liters for washing machines and toilets. Of course, the statistics likely still include some older toilet cisterns from the 1960s or outdated washing machines. Let’s round that up to 50 liters for easier calculation. This is the portion that can potentially be replaced by a cistern. Not things like pasta water, tea, or full baths.

This means that in a household with three people, about 50 cubic meters per year could potentially be substituted. However, we need to deduct times when there is a drought and the cistern runs dry. I estimate that at about 20%, leaving 40 cubic meters.

Now, consider water use elsewhere. For example, garden water meters: One lawn watering is estimated at approximately 20 liters per square meter. If someone waters 20 times a year (for example, once per week from May to August), that equals the same amount for 100 square meters.

As I said, I basically think this is a sensible approach. But financially, it will never pay off. Also, if we start talking about ethics, the very first thing we should do is remove garden water meters. Second, there should be regulations for retention cisterns. With our cistern, most of the volume would actually be air because we have to let unused water out. Third, we should talk about bathtubs. We don’t have any, but this decision had to be strongly defended here.

WilderSueden schrieb:

Crane?

In some regions, that word is also used for a (water) tap.

WilderSueden schrieb:

As I said, I basically think it makes sense to do that. But financially, it never adds up.

That just means that drinking water is still too cheap.

Hello,

Bertram100 schrieb:

I wrote about this: it’s definitely worth it, I have connected all toilets, washing machine, and garden. I have an annual consumption of 2m³ as an individual.

So you only use 5.5 liters (1.45 gallons) per day for cooking, brushing teeth, and showering? Could it be that a zero is missing there? ;-)

Best regards,

Andreas

Tolentino schrieb:

That only means that drinking water is still too cheap.

Or wastewater is too expensive. Considering the amounts involved here, there's probably not much room to increase the price. A better approach than raising drinking water prices, in my opinion, would be to promote the use of rainwater for stormwater management. We should encourage actual use instead of mandating retention, which ultimately just directs more water into the sewer system.

I don’t quite follow the logic in the first sentence, and I would also say it’s too cheap there. For the rest, I basically agree with you, and taken together it probably makes sense: drinking water discharged into the wastewater system is too cheap and should become more expensive. The same applies to stormwater discharged into the wastewater system.

Drinking water without a corresponding wastewater volume can remain inexpensive, and stormwater without a corresponding wastewater volume should be free. But how do you measure that (especially stormwater that is not discharged)? I suspect that’s why it mostly remains prohibited – because its use is difficult to monitor...

Water costs about 2€ and wastewater disposal 5€ in our area. The expensive wastewater charges undermine the cost-effectiveness because they have to be paid no matter what, regardless of where the water for the toilet flush comes from.