Hello everyone,
We are currently working on building our single-family house. The building application has been submitted, and we promptly received the first letter from the building authority stating:
Rainwater must generally be infiltrated or directed into a nearby open water body, as long as this is possible without excessive effort and damage (§ 48 b Abs. 3 WG-BW).
After a phone consultation with the building authority, we were told that rainwater is not allowed to be discharged into the sewer system due to water protection zone III. The proposed solution (if you can call it that, as they basically said “there’s no way around it”) is a cistern. Permeable paving was also mentioned for the driveway, although we’re not sure what that is for. There is no water body nearby, by the way.
We had actually considered a cistern for watering the garden but excluded it due to the cost. Now we are being forced to install one despite the financial strain, so I have a question for you.
There seem to be countless types of cisterns (according to Google). Can you tell me which type would suit our purpose and where it’s most important not to cut corners?
Kind regards
We are currently working on building our single-family house. The building application has been submitted, and we promptly received the first letter from the building authority stating:
Rainwater must generally be infiltrated or directed into a nearby open water body, as long as this is possible without excessive effort and damage (§ 48 b Abs. 3 WG-BW).
After a phone consultation with the building authority, we were told that rainwater is not allowed to be discharged into the sewer system due to water protection zone III. The proposed solution (if you can call it that, as they basically said “there’s no way around it”) is a cistern. Permeable paving was also mentioned for the driveway, although we’re not sure what that is for. There is no water body nearby, by the way.
We had actually considered a cistern for watering the garden but excluded it due to the cost. Now we are being forced to install one despite the financial strain, so I have a question for you.
There seem to be countless types of cisterns (according to Google). Can you tell me which type would suit our purpose and where it’s most important not to cut corners?
Kind regards
WilderSueden schrieb:
One alternative is simply setting up rain barrels to collect regular rainfall, even without a cistern. Provided it can be demonstrated that the capacity is sufficient for the expected precipitation...?
Just because infiltration is required, a cistern (retention tank) is not mandatory. On the contrary, anyone with a cistern still needs an overflow, either connected to the sewer system or back to infiltration (albeit on a smaller scale).
The cheapest infiltration method is to let the water flow onto a depression or larger soil area. However, this requires space, which is rarely available nowadays. The second most affordable option is an infiltration shaft. You might want to check with the local authority whether this is approvable.
W
WilderSueden17 Mar 2022 15:52Mahri23 schrieb:
The excavation was significant. But fortunately, we were still able to reuse our soil well on the property.Yes, the holes are huge. Here is a photo of my hole compared to the foundation slab. The cistern has a volume of 8 cubic meters (10.5 cubic yards).TmMike_2 schrieb:
Just build a soakaway, it might cost around 500€ and you’re done.A soakaway is definitely the right term, but 500 euros is quite far from the current actual costs. Depending on the type of soakaway, delivery might also take up to 3 months.
In many municipalities, rainwater must be infiltrated on your own property and is not allowed to be discharged into the sewer system.
The architect should take this into account and submit calculations for the appropriate soakaway or infiltration chamber. At least in our area, this needed to be reviewed and approved by the local water authority for a fee. The required size ultimately depends on the total amount of impermeable surfaces (roof, paving, terrace, etc.) and must be taken into consideration accordingly.
WilderSueden schrieb:
Yes, the holes are huge. Here is a picture of my hole compared to the foundation slab. The cistern has a capacity of 8 cubic meters (10.5 cubic yards).
I always wonder if it’s economically worth it. I had a deep well drilled through a friend.
5-inch pump, 8.5 m³ per hour (9.4 cubic yards per hour), it can run all 10 sprinklers simultaneously in summer.
TmMike_2 schrieb:
I always wonder if it’s economically viable.
I had a deep well drilled through a friend.
5" pump, 8.5 m³ per hour (around 30 cubic feet per hour), it can handle all 10 sprinklers at once during summer. Most likely not economically viable. But you can’t install or use a well everywhere or in every situation.
netuser schrieb:
"Rigole" is the right term, but €500 (about $550) is quite far from the actual current costs. Depending on the rigole, delivery can also take up to 3 months. 😉 I was also referring to rigole in the form of concrete rings used for soakaway pits.
€500 (about $550) would be the material cost assuming self-installation. At the start, he said he wanted to save money, so that was the suggestion.
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