ᐅ Rainwater Cistern: Useful? Necessary? Costs?

Created on: 30 Apr 2015 18:23
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Bieber0815
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Bieber0815
30 Apr 2015 18:23
Hi,

in a fixed-price contract, the following is offered to us:
Rainwater cistern and wastewater connection
Construction of a concrete cistern of approximately 5.4 m³ (190 ft³), up to 5 m (16 ft) from the building structure, including piping and backfilling, connected to the roof drainage system. The wastewater pipe will be routed from the foundation slab to the existing wastewater transfer chamber and connected.
What do you think?
- Are the cistern and wastewater connection directly related?
- Do we need the cistern? What is it for? What happens if we don’t have it?
- What portion of the cost do you think it accounts for (it’s not listed separately, of course, I will ask the supplier as well)?
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ypg
30 Apr 2015 18:52
A rainwater cistern was mandatory for us. Other municipalities charge a monthly fee instead. After all, the water from your roofs has to go somewhere!
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Irgendwoabaier
30 Apr 2015 19:21
For us, although it was not (yet) mandatory, we were strongly advised to install a cistern for garden irrigation. However, our water works manager is not keen on using a domestic water system for this purpose.

At the current stage, it probably won't be cost-effective here. It becomes more interesting if wastewater and rainwater are collected separately, or if wastewater charges are calculated not only based on water consumption but also according to the sealed surface area. In that case, a recalculation would be necessary...
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Bieber0815
30 Apr 2015 19:27
Do you have a submersible pump in the cistern? Or how do you get the water out? (I only know it from my parents’ house, where there is a basement, so the cistern can be almost completely emptied directly via a tap.) How is your cistern accessible for inspections? Manhole cover? Where is the cistern located?
lastdrop30 Apr 2015 19:36
A cistern is rarely cost-effective.

I don’t mind whether the lawn sprinkler runs for 5 minutes, 30 minutes, or 60 minutes...
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ypg
30 Apr 2015 19:37
Bieber0815 schrieb:
Do you have a submersible pump in the cistern?

No, it is an infiltration cistern. Water collects there naturally and is slowly released again. We don’t use it ourselves. It is located on the side, about 4 meters (13 feet) away from a downpipe.