ᐅ Infiltration of Rainwater: Which Method to Choose?

Hi,

we’re about to start building soon, and the building permit-free process was not objected to.

However, on the advice of the construction manager, we informed the local authority that rainwater would be infiltrated via a soakaway basin in the garden.

The authority states:
Rainwater must be infiltrated; a calculation of the infiltration system according to ATV-DVWK A-138 is required and must be documented. An infiltration test or an equivalent laboratory test is necessary.

We have no expertise in this matter ourselves. I’ve tried to read up a bit, but the whole topic seems very complex.

As mentioned, we specified a soakaway basin, so the local authority was able to approve it directly and did not have to forward it to the lower water authority.

One neighbor in our new development installed a soakaway tank and prefers it over a basin because it doesn’t create a “wet biotope” in the garden.

Another neighbor who has already built (using the same earthworks company/gardening contractor as we are) installed a trench soakaway system.

Now I’m wondering which option is better or more cost-effective?
Attached is the offer, which also includes the trench soakaway.

The soakaway tank seems to be quite a bit cheaper??

I hope you can help me decide the best infiltration method.

Hello,
first of all, soakaway crates, please.

Soakaway chambers require more space than soakaway boxes.

I don’t know what a “Sickeriglu” is, but we installed a soakaway shaft.
It’s basically just a few concrete rings with one on top that has a funnel-shaped form. The base was filled with coarse stone material.
I can’t tell you the cost because we had an all-inclusive quote from our earthworks contractor. You can just go to a hardware store to get an idea of the price for the part.
You’ll need to discuss the labor with your earthworks specialist.

A prerequisite for rainwater infiltration is soil that allows for permeation. This must be specified as the permeability coefficient (Kf value) in the soil report, which should be available to the construction supervisor. If infiltration is not possible, designing a soakaway trench is unnecessary. Alternatively, a soakaway pit (concrete rings, etc.) can be planned to reach permeable soil at greater depths. In all cases, a minimum distance of 1.00 m (3.3 ft) from the highest recorded groundwater level must be maintained. This applies to both soakaway trenches and soakaway pits.

If this cannot be demonstrated by a planning office, a special permit from the local authority allowing the discharge of rainwater into the sewer system should be obtained. This is usually the most cost-effective solution.

The soil we received should also be permeable. There is no clay mixed in either.

Which items specifically refer to the soakaway (other than the one labeled "soakaway," of course)? However, I find €3,300 net quite a lot for a soakaway.