Rainwater must be obligatorily infiltrated

That's the kind of soakaway shaft I meant

Rainwater must basically be infiltrated or discharged into a nearby open water body, as long as this is possible without damage at reasonable expense (§ 48 b Abs. 3 WG-BW).

Now I would like to ask a question regarding my original post.

The sentence quoted again in the letter from the authority is there, can someone explain to me what "reasonable expense" means?

I ask because we have now been in contact with a few earthworks contractors and of course always mentioned the intended cistern and the letter from the authority regarding infiltration. Each of these earthworks contractors said they would install the cistern for us but would not assume any liability for the infiltration because eventually a cistern also fills up. They all want a drainage plan from the architect with details on the implementation because they cannot rule out that at some point water will gush out of our rain gutter.

The thing is, we are already done with our architect, he has submitted the final invoice and thus everything is settled for him. Asking him again (although we don't like him) or another architect for a drainage plan will certainly cost another four-figure amount right away.
All these things added up will surely amount to a five-figure sum in the end, and all this after submitting the building application, because none of this was in the development plan.

Is there any way to try to explain that the expense is slowly no longer reasonable? Do you have any tips for us?

Unfortunately, I don't have time to read the 12 pages now to recall the details, but what is the "CURRENT state"? Have you now decided on a cistern? Why again no soakaway? ... If you don't want to contact your previous architect, then ask others.... Ultimately, I think you are overinterpreting this and any architect could "quickly" do it for a few hundred euros. You just have to find one who is willing to devote themselves to the small task in between. We quickly had our originally planned soakaway redesigned by another architect who delivered a revised plan for submission to the authorities within 3 days for a small fee. This is not the answer to your question, but ultimately I also don't understand what the possible argument regarding "reasonable effort" brings you if at the end of the day the water still gushes from the rain gutters? ;)

Hello, we also built in BaWü and had the same requirement. After a neighbor complained several times to the building authority about the (officially mandated) soakaway pit, we were able to "get rid" of this requirement through a Tektur. The building authority eventually agreed that we could discharge the water directly into the sewer. Additionally, we used permeable paving in the driveway to drain the rainwater on the property.

I am still reviewing our options and one option for me is to see if we can get around it, since the effort might not be justifiable or the effort is too high.
Because on the one hand, we have to cut things for cost reasons, and on the other hand, such requirements suddenly come up. I think if there were such a requirement, it would be written in the development plan (which dates from 2019), and the sentence with "justifiable effort" must have some meaning.
I just think they could have told us much earlier, then we might have saved the costs of the subsequent plan change; I have been in contact personally with that official from the office x times...


That sounds very interesting, can you explain it to me in more detail and do you maybe also have sketches for it? What do you mean by Tektur? Permeable pavers are, I think, an option for the driveway, but I think the roof will be mostly affected and so far we have no solution for that.

That sounds very interesting, can you explain it to me in more detail and do you maybe also have sketches for it? What do you mean by Tektur? Permeable paving is, I think, an option for the driveway, but I think the roof will be affected the most and so far we have no solution for that.

I don’t have sketches, but a Tektur is simply a subsequent change to the building application. We only had to submit a new wastewater plan. In this, the path of the rainwater from the roof goes directly into the sewer; previously there was a soakaway pit in between. But we first coordinated this approach with the officer at the building authority and then submitted it. Just call your officer ;-)

For us, the driveway was also important, as it’s almost 160 sqm ;-)