Say, what is going on here!? Crazy!
What do you always use as a reference? It constantly reads as if a cistern costs 10k... What capacity are we even talking about here? It’s probably just a three-digit amount, you can’t compare that to a carport and the like... Get a showroom piece from the hardware store (that’s what we did) and you can save a lot.
It’s not existential, just a plain cistern
If you have no idea about something like that (at least we), when building a house we usually calculate directly with 5,000€-10,000€. That’s how it’s been with almost everything so far, which is why you become so jaded and can’t believe anything else.
Although, as you could read further, there are additional costs with the cistern that definitely suggest a four-digit sum.
Call the municipality, they should also have a soil survey from the development. That should be enough for the assessment. If you are building with a basement, I would definitely find out if you have to build with a white tank on clayey soil. If yes, you can basically forget infiltration on the property.
It’s still an undeveloped plot, so there won’t be anything yet. We really hope that a white tank isn’t necessary; the slope will already demand enough additional costs from us.
The excavation was not insignificant. But luckily we could still use our soil well on the property.
After all, we still had to add about 50 cm.
Because of the slope, we are quite sure that we will manage this soil pretty well, on the contrary, we strongly expect to need a lot more soil.
Just because you have to let water infiltrate doesn’t mean a cistern (= retention) is mandatory. On the contrary, if you have a cistern, you still need an overflow, either to the sewer or again via infiltration (albeit smaller sized).
What does a solution with a cistern and infiltration look like? Two holes next to each other or can you cleverly put them one above the other?
The cheapest variant of infiltration is simply directing the water onto a depression or a larger soil surface. But you need space for that, which nowadays hardly anyone has. The second cheapest variant is the infiltration shaft. Ask the authorities whether that is approvable.
Unfortunately, we don’t have that space... An infiltration shaft sounds like the infiltration pit mentioned by tomtom79. How exactly can one imagine that?
Yes, the holes are huge. Here’s a picture of my hole compared to the floor slab. The cistern has 8 cbm.
That’s intense!!! So either it’s a very small house or a very large cistern!!! I’m guessing the latter...
The architect should actually take this into account and submit a calculation for the appropriate soakaway/infiltration shaft.
At least for us, this had to be reviewed and approved by the "Lower Water Authority" for a fee.
The calculated size ultimately depends on the total amount of sealed surfaces (roof, paving, terrace...) and must be taken into account accordingly.
Yeah, the architect... That’s a topic on its own!! Woulda, coulda, shoulda is all I can say... Unfortunately, it seems to me that the diploma attached to the building application was bought in Thailand, at least as far as competence is concerned...
We have to submit a "wastewater technical calculation," I’m very curious how he’ll do that...
I also meant soakaways in the form of concrete rings for infiltration shafts.
500€ would be the material cost for DIY, at first he said he wanted to save, hence the suggestion.
Uh, well he still wants to save and is thankful for the hint! I now have to first understand what a soakaway is and what the difference is compared to infiltration shafts and pits.
I don’t know compared to a well. Compared to tap water definitely, because in general you have fresh water = wastewater, and you don’t have to treat water for the garden in an elaborate way. And with the cistern you save a few Euros on rainwater.
Those are also our reasons why we at some point thought it makes sense to install a cistern. Garden irrigation...
Not at all, if you install appropriate meters for garden water and don’t pay wastewater charges.
What does that mean? A meter for garden water?
Permeable pavement is already enough of a nuisance because the subsoil infiltrates water two orders of magnitude less effectively than the pavement laid on it.
What do you mean by that? Why is it a nuisance?