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Sockeldichtung13 Jul 2025 11:56Good morning,
Our outdoor landscaping will be done soon, and at the spots where the paving meets the house, a base channel (ACO Profiline) will be installed. We are now considering whether to drain the base channel into the sewer system or into an infiltration basin.
Basically, we would prefer to connect it to the sewer. However, the bottom edge of the base channel is below the backflow level. In case of backflow, wastewater could potentially be pushed into the base channel.
The soil is sandy, and the groundwater level is relatively high (about 1-2 m (3-6.5 ft) deep).
What do you think?
Our outdoor landscaping will be done soon, and at the spots where the paving meets the house, a base channel (ACO Profiline) will be installed. We are now considering whether to drain the base channel into the sewer system or into an infiltration basin.
Basically, we would prefer to connect it to the sewer. However, the bottom edge of the base channel is below the backflow level. In case of backflow, wastewater could potentially be pushed into the base channel.
The soil is sandy, and the groundwater level is relatively high (about 1-2 m (3-6.5 ft) deep).
What do you think?
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wiltshire13 Jul 2025 12:16First thought: A dedicated backflow preventer for the connection of the base gutter.
Sockeldichtung schrieb:
The ground is sandy, and the groundwater level is relatively high (about 1–2 m depth (3–6 feet)). Where do you drain your gutters?
I would also drain the base drainage channels there.
A soakaway only as an overflow behind a rainwater tank, so you have water for irrigation and the environment benefits.
Do you have a basement?
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Allthewayup13 Jul 2025 19:49How much does the groundwater level fluctuate in your area? We have connected the gutters to the soakaway chamber for the rainwater. Our backflow level is also at ground level. However, the groundwater here has never reached ground level — it has always been well below it, so it was clear that the water would infiltrate in the soakaway chamber. If you live in a flood-prone area and there is a chance that rainwater or groundwater could ever reach or even exceed ground level, it’s all the same. Either nothing drains anymore, or water pushes back out. A backflow prevention device only provides a short-term solution in the latter case, because water then pushes back through the street or neighbors’ sewer lines, etc.
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Sockeldichtung13 Jul 2025 20:50Thank you for the feedback.
The rain gutters drain into the sewer system, which is allowed here as well. We do not have a basement. In the event of backflow, wastewater could potentially rise a few centimeters in the rain downpipes but should not overflow. The bottom of the gutter is at least 9 cm (3.5 inches) below the backflow prevention level (determined as the next highest exit point from the sewer system above our connection point). This means that without the proposed additional backflow protection, the wastewater would spread in the gutter and reach the building base.
Connecting directly to the sewer system with additional backflow protection would certainly be the premium option but would also involve some extra costs.
The groundwater does not reach the surface. Even before we raised the ground, the groundwater did not reach the surface. The neighboring plots are partly 20–40 cm (8–16 inches) lower. This means that before water on our property stops seeping away due to the groundwater level, these neighboring plots would already be flooded. In the case of a once-in-a-century rain event flooding the entire construction area, we would have a problem anyway, as Allthewayup mentioned.
We also have a fairly large roof overhang, so not much water should actually accumulate in the base gutter.
With this additional information, are there still serious concerns about draining via an infiltration shaft, as described by Allthewayup?
The rain gutters drain into the sewer system, which is allowed here as well. We do not have a basement. In the event of backflow, wastewater could potentially rise a few centimeters in the rain downpipes but should not overflow. The bottom of the gutter is at least 9 cm (3.5 inches) below the backflow prevention level (determined as the next highest exit point from the sewer system above our connection point). This means that without the proposed additional backflow protection, the wastewater would spread in the gutter and reach the building base.
Connecting directly to the sewer system with additional backflow protection would certainly be the premium option but would also involve some extra costs.
The groundwater does not reach the surface. Even before we raised the ground, the groundwater did not reach the surface. The neighboring plots are partly 20–40 cm (8–16 inches) lower. This means that before water on our property stops seeping away due to the groundwater level, these neighboring plots would already be flooded. In the case of a once-in-a-century rain event flooding the entire construction area, we would have a problem anyway, as Allthewayup mentioned.
We also have a fairly large roof overhang, so not much water should actually accumulate in the base gutter.
With this additional information, are there still serious concerns about draining via an infiltration shaft, as described by Allthewayup?
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