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.
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.
Is there a general rule of thumb for how much rainwater storage capacity one should have? Somehow, the amount the roof delivers during heavy rainfall and the water used in the weeks before and after need to be reasonably balanced. Otherwise, the cistern either empties too quickly or constantly overflows, requiring the excess to be drained away.
I would like to install a drip irrigation hose both under the lawn and in mulched areas. 100 meters (330 feet) probably won’t be enough, more like 200 meters (660 feet). The hose has an outlet every 30 cm (12 inches), each releasing 1.6 liters (0.42 gallons) of water per hour. That means: with 200 meters (660 feet) of drip hose, I can deliver one cubic meter (264 gallons) of water to the garden in one hour. To avoid forgetting to turn off the pump, I would probably install a push button with a timer switch that shuts off after one hour.
If watering takes place three times a week for one hour each time, and the cistern holds 10 cubic meters (2,641 gallons), it would be empty after three weeks. That could be tight under current weather conditions...
Another question: What type of pump would be suitable that can both deliver the required water volume and generate sufficient pressure for 200 meters (660 feet) of drip hose? And is there a way to install something that allows you to monitor whether there is pressure in the system?
Matthias
I would like to install a drip irrigation hose both under the lawn and in mulched areas. 100 meters (330 feet) probably won’t be enough, more like 200 meters (660 feet). The hose has an outlet every 30 cm (12 inches), each releasing 1.6 liters (0.42 gallons) of water per hour. That means: with 200 meters (660 feet) of drip hose, I can deliver one cubic meter (264 gallons) of water to the garden in one hour. To avoid forgetting to turn off the pump, I would probably install a push button with a timer switch that shuts off after one hour.
If watering takes place three times a week for one hour each time, and the cistern holds 10 cubic meters (2,641 gallons), it would be empty after three weeks. That could be tight under current weather conditions...
Another question: What type of pump would be suitable that can both deliver the required water volume and generate sufficient pressure for 200 meters (660 feet) of drip hose? And is there a way to install something that allows you to monitor whether there is pressure in the system?
Matthias
G
garfunkel9 Aug 2018 15:29There are maps showing rainfall amounts and various calculators that can directly determine the appropriate cistern size.
The amount of water you can collect is logically the amount available to you.
A 10 m³ (350 ft³) cistern... I don't know anyone who has such a huge one in their garden. Most are in the 1 to 3 m³ (35 to 105 ft³) range, which is already quite substantial; some even have 5 m³ (175 ft³).
No one here waters their lawn...
A 200 m (650 ft) hose with drip irrigation sounds challenging to me. The pressure has to be maintained all the way to the very end, which means the pressure at the beginning is higher than at the far end. Therefore, the emitters at the start will deliver much more water into the soil than those at the very end. I don’t think this will work well without some kind of pressure regulation.
I also think that might be overdoing it. Although we have experienced droughts here and there this year, with simple surface irrigation running in the evening, at night, or in the early morning, it should still be possible to supply more than enough water to the soil to prevent drying out here in Germany.
The amount of water you can collect is logically the amount available to you.
A 10 m³ (350 ft³) cistern... I don't know anyone who has such a huge one in their garden. Most are in the 1 to 3 m³ (35 to 105 ft³) range, which is already quite substantial; some even have 5 m³ (175 ft³).
No one here waters their lawn...
A 200 m (650 ft) hose with drip irrigation sounds challenging to me. The pressure has to be maintained all the way to the very end, which means the pressure at the beginning is higher than at the far end. Therefore, the emitters at the start will deliver much more water into the soil than those at the very end. I don’t think this will work well without some kind of pressure regulation.
I also think that might be overdoing it. Although we have experienced droughts here and there this year, with simple surface irrigation running in the evening, at night, or in the early morning, it should still be possible to supply more than enough water to the soil to prevent drying out here in Germany.
I have read that the Netafim drip hose should not exceed 170 meters (560 feet) in length. It is pressure-compensated, meaning it is supposedly designed to ensure that an equal amount of water drips from each hole, regardless of the pressure.
In my opinion, the lawn definitely needs to be irrigated because otherwise it will suffer too much from dryness. Additionally, it gradually gets taken over by ants that eat the roots and eventually destroy it completely. So far, I have been watering the lawn with pop-up sprinklers, but after ten years they seem to be reaching their mechanical lifespan.
With drip hoses, the water is delivered exactly where it is needed, and there are no losses due to wind or evaporation. At least, that’s what the manufacturers claim. I have no personal experience with this yet.
Matthias
In my opinion, the lawn definitely needs to be irrigated because otherwise it will suffer too much from dryness. Additionally, it gradually gets taken over by ants that eat the roots and eventually destroy it completely. So far, I have been watering the lawn with pop-up sprinklers, but after ten years they seem to be reaching their mechanical lifespan.
With drip hoses, the water is delivered exactly where it is needed, and there are no losses due to wind or evaporation. At least, that’s what the manufacturers claim. I have no personal experience with this yet.
Matthias
I have recalculated everything several times and keep coming to the conclusion that the effort for using rainwater in the garden never really pays off. The tap water is simply too cheap here in Berlin. Especially since we have a second meter and don’t have to pay sewage fees for the water that soaks into the ground in the garden. Also, due to our geology and deep wells, we don’t have any water supply issues here in Berlin, even during a summer like this one.
Therefore, I wonder if it’s even worth the effort to go through all this when water comes straight from the tap...
Matthias
Therefore, I wonder if it’s even worth the effort to go through all this when water comes straight from the tap...
Matthias
S
Schwimmbutz18 Aug 2018 11:04On our plot of land (in NRW), rainwater must infiltrate on-site. Since I need to install a soakaway or similar system anyway, I can integrate a cistern with an overflow directly. That way, the additional costs don't seem that bad.
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