Connection types
Infiltration, Canalisation or Detention
Solutions for rainwater disposal
By installing a cistern, you can save money on wastewater charges. This is because you are making a significant contribution to better infiltration and relieving the burden on the sewer system during heavy rainfall. But what happens when the cistern is full? There are additional infiltration systems that can be used to drain the excess rainwater into the sewer system or directly into the groundwater. You can find out which type of connection is right for you on this page.
Only infiltration trench
Potential savings
Stormwater utility fee for associated impermeable area
Advantages
Affordable design
Disadvantages
Terrain must be suitable
Recommendation
The optimal solution where there is favourable terrain, especially in Baden-Württemberg, because Infiltration through active topsoil layers requires no building permit whereas French drains need approval.
Only French drain
Potential savings
Stormwater utility fee for associated impermeable area
Advantages
Concealed infiltration
Disadvantages
Checking on the soakaway is rather more involved
Subject to approval In some German Federal States (for instance Baden-Württemberg)
Recommendation
The most common solution for medium-sized infiltration systems with good accessibility for trucks to deliver drainage gravel.
Only infiltration with dry well using gravel
Potential savings
Stormwater utility fee for associated impermeable area
Advantages
Easy to install
Soakaway can be checked
Disadvantages
Soakaway trench may need to be filled up with considerable volumes of suitable gravel.
Recommendation
The easiest and cheapest solution for medium-sized infiltration systems with good accessibility for trucks to deliver drainage gravel.
Rainwater harvesting with infiltration trench
Potential savings
Up to 50 % of household drinking water
and stormwater utility fee of associated roof area
Advantages
Easiest system to install
Lowest investment costs for infiltration
Disadvantages
Only solutions using a basket filter suitable
Terrain must be suitable
Recommendation
With favourable terrain conditions, the optimal solution with maximum possible savings. Especially in Baden-Württemberg, infiltration through active soil layers is a more reasonable solution than a French drain which requires approval.
Rainwater harvesting with French drain
Potential savings
Up to 50% of household drinking water
and stormwater utility fee of associated roof area can be saved
Advantages
No garden area is taken up for use as a soakaway
Disadvantages
Only solutions using a basket filter suitable
Recommendation
The most common and best solution for flat plots. This version offers the maximum possible savings. The number of necessary soakaway crates depends on the roof area and soil type.
Rainwater utilization with sewer connection
Potential savings
Up to 50 % of household drinking water
Relief on stormwater utility fee
Advantages
All filter options can be used
Easiest system to install
Disadvantages
Usually not complete exemption from stormwater fee
Recommendation
If a soakaway is not technically possible or only at great expense, then this is the optimal solution.
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Detention cistern without useable volume and 100 % detention volume
Potential savings
Relief in the calculation of impermeable area, and thus reduction of stormwater fee.
Advantages
Lowest investment costs, since almost no tank accessories are required
Disadvantages
Not possible to make use of rainwater
Recommendation
If a detention tank is required and the rainwater cannot be or is not wished to be used, this retention option is the right one.
Detention cistern with 50 % useable volume and 50 % retention volume
Potential savings
Up to 50 % of household drinking water
Relief in the calculation of impermeable area, and thus reduction of stormwater fee.
Advantages
Advantages of rainwater harvesting and retention at the same time
Disadvantages
Only 50 % of the tank volume is available for use. A larger tank should be chosen.
Recommendation
If a detention tank is required and also rainwater is to be used, this retention option is ideal.
Lassen Sie lieber Wasser versickern statt Geld: