ᐅ Cistern in the garden / driveway

Created on: 31 Jan 2020 22:28
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Piotr1981
We are planning to build or buy a rainwater cistern. Has anyone here had experience with this? The cistern is primarily intended for garden irrigation.
According to the development plan, rainwater infiltration on the property is not allowed.

Concrete?
Plastic?
What else should we consider?
Toilet connection?
Where to position it?

I would like to take this into account directly during the excavation for the foundation slab and have the hole dug at the same time.

Looking forward to your ideas and tips.
kaho6741 Feb 2020 23:13
Just don’t make it too small. It’s getting hotter and drier here all the time. Also, in the end, it hardly matters whether you dig 3 meters (10 feet) deep or 5 meters (16 feet). Only the excavator arm needs to be long enough and the pump powerful enough.
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Piotr1981
1 Feb 2020 23:18
rick2018 schrieb:

You can easily use that up.
Let’s say you have 200m2 (2,150 sq ft) of lawn. The water requirement for lawn in summer is about 20 liters per m2 (2 gallons per 10 sq ft), which means 4,000 liters (1,057 gallons) per week! This does not include hedges, trees, and so on. During the establishment phase, you need even more water. So with 10,000 liters (2,642 gallons), you will last just under three weeks.
An architect usually has no clue about this unless they are a landscape architect.
Trust me, we have several properties in the family with cisterns and automatic irrigation. My sister is struggling with only 7,500 liters (1,982 gallons).
I have also helped some forum members with irrigation planning.
You will get dirt in every cistern, though less with an inlet filter. Still, you have to clean it out every 2 to 3 years at the latest. It causes fewer problems in a large cistern. Nowadays, always use a pump with a mid-level suction.


Thanks!
I’ll get back to you when the time comes. It’s definitely quite a complex topic.
rick20181 Feb 2020 23:31
The optimal position depends on your plot and the house.
Try to position it so that you can collect runoff from all the roof, terrace, and paved surfaces.
The soil and location will also determine which type of cistern makes the most sense (shallow, horizontal cylinder, or vertical...). For plastic cisterns, you could check options like Graf, for example.
The price difference between installing a 10,000-liter (2,640-gallon) or 15,000-liter (3,960-gallon) tank is small. For a large excavator, it’s just a matter of one or two extra scoops of earth...
One002 Feb 2020 13:18
We have approximately 250 sqm (2,690 sq ft) to irrigate. The concrete cistern holds 10,000 liters (2,640 gallons), which usually just lasts through the spring and summer. I have already had to refill it twice.

A concrete cistern should be cleaned at most every five years. Solid material settles at the bottom over time, and with a gentle inflow, it won’t be stirred up. This naturally regulates the environment inside, so the water does not go bad. I regularly clean the inlet filter inside the cistern; it has never smelled. The cistern was built in 2014 and has not been cleaned so far. However, this applies only to concrete, which is said to have a positive effect on the water’s pH compared to plastic.

A pump or its intake should maintain a minimum distance of 30 cm (12 inches) from the bottom due to the mentioned deposits.
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Stefan890
3 Feb 2020 20:54
rick2018 schrieb:

Nowadays I always use a pump with a centrifugal middle-water suction.
Can you recommend a specific model? What should one pay attention to?
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Bookstar
3 Feb 2020 21:14
Stefan890 schrieb:

Can you recommend a specific model? What should one pay attention to?
Hang it with a rope in the center 30cm (12 inches) above the ground, problem solved.