Menu

Usage methods

Regenzisterne von Speidel wird in Grube gehoben

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 infiltration trench
Only infiltration trench

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 French drain
Only French drain

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.

Only infiltration with dry well using gravel
Only infiltration with dry well using 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 infiltration trench
Rainwater harvesting with infiltration trench

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
French drains are subject to approval in Baden-Württemberg

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 harvesting with French drain
Rainwater harvesting with French drain

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.

Rainwater utilization with sewer connection
Rainwater utilization with sewer connection

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 without useable volume and 100 % detention volume
Detention cistern without useable volume and 100% detention volume

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.

Detention cistern with 50 % useable volume and 50 % retention volume
Detention cistern with 5 0% useable volume and 50 % retention volume