Hello,
I have a question regarding the offered cistern. Our development plan states the following:
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?
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?
Hello,
I can only speak for the Nuremberg area, but here in Franconia, garden wells are mostly no longer permitted.
Regards,
Andreas
Joedreck schrieb:
Are garden wells out of fashion now, or are they not allowed in many communities?
I can only speak for the Nuremberg area, but here in Franconia, garden wells are mostly no longer permitted.
Regards,
Andreas
andimann schrieb:
That’s official... here I get about 2,500 m³ (88,300 cubic feet) of fresh water. I won’t need that much in my garden in my lifetime... And that’s exactly why a rainwater tank—officially installed—is never really practical. Such a tank can definitely be worthwhile for someone who does all the work themselves. But if you have a company do it in a quick and easy way, it won’t achieve much.
Whether it’s morally acceptable to use fresh water for irrigation is up to each individual to decide. On the other hand, many liters also flow away daily through the toilet...
C
Changeling14 Feb 2018 11:42andimann schrieb:
That’s official... here I get about 2,500 m³ (88,300 ft³) of fresh water. I won’t need that much for my garden in my lifetime... If you only have a lawn, probably not. We have several flowerbeds and a greenhouse, so the demand adds up. Unfortunately, I couldn’t find reliable figures quickly, but with an estimated 150 m³ (5,300 ft³) of garden water per year, it takes about 15 years for the rainwater tank to pay off. Since we’re building new, that’s at least our goal.
However, the tank would need to be consistently filled optimally, and no water should infiltrate the ground, because with 700 mm (27.5 inches) of annual rainfall and a 200 m² (2,150 ft²) roof area, you only get about 140 m³ (4,950 ft³) of rainwater— and not just in summer, when we need most of the water. So if I estimate 100 m³ (3,530 ft³) of usable rainwater, the break-even point extends to over 20 years... which makes it somehow uneconomical.
Maybe it’ll just come down to rain barrels and using fresh water after all :-/
Hello,
Your calculation is still quite optimistic. Our neighbors installed a cistern back then (I believe 4m³ [5.2 yd³]) and they say it fills only about 5-8 times a year. With around 100m² (1,076 ft²) of roof area, that results in about 65m³ (85 yd³) of usable rainwater. Unfortunately, it usually rains when I don’t need the cistern. And in summer, we often experience dry periods lasting several weeks (even last summer, which apparently was very rainy in many areas).
Economically, this doesn’t add up. Although water prices are likely to rise, you also have to factor in financing costs for the 4,600 euros.
It only becomes interesting if you either need to build an infiltration system anyway or if having a cistern means you no longer have to pay a fee for stormwater runoff.
Best regards,
Andreas
Changeling schrieb:
However, the cistern would always need to be optimally filled and no water should infiltrate, because with 700mm (28 inches) of rainfall per year and 200m² (2,150 ft²) of roof area, only about 140m³ (185 yd³) of rainwater will be collected – and not just in summer, when we mostly need the water. So if I calculate with 100m³ (131 yd³) of usable rainwater, we're already looking at a break-even point of over 20 years... which then somehow becomes unprofitable.
Your calculation is still quite optimistic. Our neighbors installed a cistern back then (I believe 4m³ [5.2 yd³]) and they say it fills only about 5-8 times a year. With around 100m² (1,076 ft²) of roof area, that results in about 65m³ (85 yd³) of usable rainwater. Unfortunately, it usually rains when I don’t need the cistern. And in summer, we often experience dry periods lasting several weeks (even last summer, which apparently was very rainy in many areas).
Economically, this doesn’t add up. Although water prices are likely to rise, you also have to factor in financing costs for the 4,600 euros.
It only becomes interesting if you either need to build an infiltration system anyway or if having a cistern means you no longer have to pay a fee for stormwater runoff.
Best regards,
Andreas
C
Changeling14 Feb 2018 12:24andimann schrieb:
Economically, this won’t be profitable. Although the water price will probably increase, you also have to factor in the financing costs for the 4600 € against it. The water price here has been stable since 2001, and according to Google ("development of water prices in Germany"), it roughly keeps pace with inflation. So unless there are really drastic climate changes and drinking water becomes scarce (like currently in Cape Town), I don’t expect major changes here...
andimann schrieb:
It only becomes interesting if you either have to build an infiltration system anyway or if a cistern means you no longer have to pay stormwater fees. That’s exactly my point. In 20 years, I will be paying over 6000 € for stormwater charges on my 200m2 (2150 sq ft) area... you could do quite a lot with that money.
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