ᐅ Cistern Dimensions – Building Plan Tips

Created on: 1 Jul 2016 15:22
M
McEgg
Hello,
I have a question regarding the offered cistern. Our development plan states the following:
C 3. Water Management
C 3.1 The hardening of open areas should be limited to a minimum. Parking spaces and driveways should be paved with permeable surfaces (e.g., grass pavers, paving with grass joints, gravel turf, or similar).
C 3.2 The uncontaminated rainwater collected on private properties must be retained on the site and infiltrated or used as non-potable water.
Only wastewater must be directed to the sewage treatment plant.
C 3.3 A management concept must be developed and coordinated with SGD Süd, RS WAB, Neustadt for the disposal/use of rainwater that is not significantly polluted.

The general contractor suggested that we install a cistern in the garden.
The current offer includes a cistern with a capacity of 4,000 liters (1,057 gallons).
The plot is approximately 540 m² (5,813 sq ft) in total. The house will be roughly 10 m x 11 m (33 ft x 36 ft), plus a double garage of 6 m x 6 m (20 ft x 20 ft), and a terrace...
Do you think this size is too small?
andimann14 Feb 2018 12:55
Hello,
Changeling schrieb:
In 20 years, I will pay over €6000 for my 200m2 (2150 sq ft) area in stormwater fees...

How do you figure that??? That would be €42 per cubic meter of rainwater. I think that sounds quite exaggerated..... I would rather dispose of the water as hazardous waste, that would be cheaper

Best regards,

Andreas
C
Changeling
14 Feb 2018 13:02
andimann schrieb:
How do you come to that???

From the current wastewater fee schedule: "[...] for rainwater discharged into public sewer systems (stormwater fee), charged per m2 of assessed surface area per year: from 01/01/2017 €1.56."
For 200 m2 (2150 sq ft) of sealed or roof area over 20 years, that amounts to €6240 (assuming the rate stays the same).
andimann14 Feb 2018 13:23
Oh, right... together over 20 years...

Well... 4,600 € plus about 1,400 € in interest on the 4,600 € is also 6,000 €. If nothing breaks, you’re basically at the break-even point after 20 years.

If you entirely avoid the stormwater charge, then it’s somewhat reasonable.

I would definitely consider that if I were you.

We would still pay the stormwater charge despite having a cistern. The city argues that a large part of the rainfall doesn’t occur during the irrigation period but from September to May. And sooner or later, that water runs off via the overflow (which is required here) into the sewer system. That’s not entirely wrong…

Best regards,

Andreas
8
86bibo
14 Feb 2018 18:10
From a purely economic perspective, a rainwater cistern is likely worthwhile for very few people. However, conditions vary everywhere. I cannot avoid wastewater charges by having a second meter and therefore pay €4.50 per cubic meter. If I could also save money on sealed surfaces (which is not the case for me), it might make financial sense. Those who pay only around €2 for fresh water should probably skip it.

The same applies to solar thermal systems. They usually become cost-effective only after about 20 years. I would rather save water with a cistern than save a small amount of fuel or electricity.
P
Payday
14 Feb 2018 19:09
Why shouldn’t the submeter work for you? What requirements do you have? Nearly all of these requirements can be interpreted differently from a legal perspective.

For example, in our case it says: the submeter must be located in the branch line to the external water tap.

I explained to them, referring to DIN standards and others, that there must not be a branch line there at all, because standing water can accumulate, which could lead to contamination of the entire street’s water supply. Consequently, I was allowed to install the water meter behind the frost-proof external water tap, provided I install another tap (a Gardena-style distributor) behind the meter. This way, I complied with the exact wording of their regulations.

What I still need to arrange is the “fixed installation.” For that, I wanted to build a small “housing.”
A
Alex85
14 Feb 2018 19:17
There are water supply companies that simply do not allow this.