ᐅ Allowing Rainwater to Infiltrate the Ground – The Most Cost-Effective Option?

Hello everyone,

I need to get rid of my rainwater.
Discharging into the sewer system is not allowed in our community.
At first, I wanted to install a flat tank with a pump and be done with it.
Now my neighbor told me about a well, which is possible here and is now being implemented cost-effectively.
I no longer need the rainwater, but I have already connected 100mm (4 inches) KG pipes to my downspouts and laid them out over about 16m (52 feet). The attached sketch basically shows my current installation.

My problem is this: Various forums and my execution drawing say the infiltration basin should be about 30cm (12 inches) deep. However, my pipe end is at a depth of 1m (3.3 feet).
I didn’t want to skimp on the slope to ensure no water stands, and frost protection should also be considered.

The question is: What (more cost-effective) alternatives do I have with my pipe end at 1m (3.3 feet) depth?

The groundwater level here is very high during the relevant months. Our house connections could only be installed with a 2-month delay in January using a pump to remove the water.

Thanks in advance!

What do you mean you didn’t want to be stingy with the slope?

There is a good reason why a certain slope is usually recommended.
Especially when it comes to flushing the pipe, having too steep a slope can be a disadvantage.
Heavier particles (dirt) might get caught because the water flows past too quickly, allowing debris to settle over time and eventually clog the pipe.

We have a concrete inspection shaft with a cover in the garden. It has a diameter of about 1 meter (3 feet) and is approximately 3 to 4 meters (10 to 13 feet) deep. Its overflow leads into a buried gravel pit filled with 4 cubic meters (140 cubic feet) of gravel, which was first covered with a geotextile fabric and then covered with soil.

What type of drainage system have you applied for, what was approved, and who planned it?
I don’t want to sound like a bureaucrat, but do you really know what you’re doing? I think your neighbor isn’t referring to a well but to a soakaway pit. However, that’s not a 1-meter (3.3 feet) deep pipe. Especially with a high groundwater level, I don’t believe it works as simply as you have outlined.

Alex85 schrieb:
What type of drainage did you apply for, what was approved, and who planned it?
I don’t want to act like a bureaucrat, but do you really know what you’re doing? I think your neighbor isn’t talking about a well but a soakaway or infiltration pit. That’s not just a 1m (3 ft) deep pipe. Especially with a high groundwater level, I don’t believe it works as simply as you have outlined.

He probably means the well, as with a high groundwater level it’s a more affordable and reliable water source than a cistern.

We also want a well but had to install a small cistern due to clear regulations.

I agree with you that it should at least be properly planned [emoji14]

What is the groundwater level?

I would just calculate two soakaways and have them installed. That's it.

Regarding the well, I would first have a water analysis done.

Unfortunately, I recently found out that our well water is generally fine except for the zinc content. The concentration is so high that the water cannot be used for irrigation.

About the cistern:

I built one a few years ago myself. Since I didn’t want to go through the process of obtaining a building permit/planning permission from the local water authority—which also costs money—and I didn’t know where to install infiltration trenches because there are many trees and shrubs here, only a surface infiltration system was feasible. So I slit sewage pipes and laid them on one side of the garden. When needed, an inexpensive pump starts and drains the tank a little. The water then disperses over a length of about 10 meters (33 feet).