Which scenario fits you?

We've built a calculator for the most common situations – each with relevant default values and answers to the scenario's questions.

House & single-family home

Single-family home on a combined sewer with roof and surface water. The classic situation where there is typically a refund to be had.

If your rainwater is already on a separate sewer, there is usually no refund – but an infiltration trench can still pay off for climate-proofing.

Large roof and paved areas. Refund and sizing are calculated the same way, just on a bigger scale.

Roofs and driveways are typically common areas – the decision lies with the homeowners' association, not the individual owner.