ᐅ Who has experience with cisterns?

Created on: 17 Jul 2018 13:29
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Changeling
By installing a cistern with an emergency overflow connected to the sewage system, we can reduce the rainwater charge to 10% of the usual estimated amount. If the overflow is directed to infiltration, it can even be reduced to 0%. This would save us about €250-300 per year, which is why we are interested in installing a cistern.

Unfortunately, there are many different suppliers, options, and prices available here, so my question is: What did you pay attention to when purchasing, what can you recommend or not recommend, and what were your prices?

Our key requirements:
- We would like a capacity of around 6000-7000 liters (1600-1850 gallons), as we have a large garden with many beds.
- A convenient withdrawal point is essential for us; preferably a pump with good pressure and a type of faucet that can be mounted at waist height.
- So far, I am leaning toward a concrete cistern.
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Pianist
18 Aug 2018 11:13
I have to manage my own rainwater infiltration, and I am doing that. That’s why the idea came up to store it instead of letting it infiltrate immediately. But I estimate that the whole setup (large concrete cistern, excavation work, pump, and so on) would cost around 5,000 EUR. And I could only store about 9,000 liters (2,378 gallons). That would be used up after three weeks. And here, we had hardly any rain for three months. It wouldn’t pay off in 20 years...

Moreover, a cistern always carries the risk of buoyancy if it is empty. One could argue that if there’s heavy rain and the groundwater level rises, the cistern would be full; and if it’s emptied, the groundwater level would be low because it’s dry. But who knows...

Matthias
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Schwimmbutz
18 Aug 2018 11:20
Our groundwater is very deep, so nothing floats up. Therefore, a plastic cistern is sufficient.
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Pianist
18 Aug 2018 11:27
Well, my house is occasionally surrounded by water. That’s why it is waterproof from the bottom. I will probably leave it that way...

Matthias
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Schwimmbutz
18 Aug 2018 11:53
You are probably right
C
Changeling
24 Aug 2018 08:05
We have now received a good offer for the rainwater collectors (over 9,000 liters (2,378 gallons) with pump, etc., for less than €2,500 (without excavation work)). Now the question is whether we should go for the full amount and have a regulated inflow. Does anyone have experience with this, or have you had no regulated inflow and no problems?

Supposedly, this causes less stirring up of dirt and improves water quality because oxygen is introduced from below. Since we want to use the water not only for the garden but also for the animals, we are currently considering whether it is "worth it." A floating intake is planned anyway.

@Bieber0815 – I think you were the only one here who mentioned the inflow and said it is not necessarily necessary?
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dab_dab
24 Aug 2018 08:47
A tranquil inlet should cost around 100 € (approximately $110) excluding some PVC pipes and is a highly recommended accessory. Alternatively, you can build it yourself entirely from standard PVC components. However, you should not omit it.

Besides the mentioned oxygen input, the main advantage is the reduced disturbance of the gradually forming sediment at the bottom. This results in less overall biological activity, and therefore less biomass and oxygen consumption.