Skip to content
CalcWolf Home Regentonne-Rechner
Home

How Much Rainwater Can You Collect?

Calculate rainwater collection potential from your roof area and local rainfall.

📅 Updated April 2026 Formula verified 📖 4 min read 🆓 Free · No sign-up

Berechnung

Liter = Dachflaeche (m²) × Niederschlag (mm) × 0,9. 100 m² Dach, 10 mm Regen: 900 Liter. Deutschland: ~700-800 mm/Jahr. 100 m² Dach: ~63.000 Liter/Jahr nutzbar! Regentonne 300-500 Liter: 50-150 €. Unterirdische Zisterne: 1.000-3.000 €.

Sparen

Einige Kommunen gewaehren Reduzierung der Niederschlagswassergebuehr bei eigener Versickerung/Sammlung.

⚡ CalcWolf Insight

A single rain barrel saves approximately 1,300 gallons of tap water per year — about $15-20 on your water bill. The environmental benefit is larger: it reduces stormwater runoff (the #1 source of urban water pollution) by capturing roof water that would otherwise flow into storm drains carrying pollutants to local waterways.

Frequently asked questions
Wie viel kann ich sammeln?
100 m² Dach: ~63.000 L/Jahr. Eine 300L-Tonne füllt sich bei 3,3 mm Regen.
Gebuehren sparen?
Ja — Niederschlagswassergebuehr kann reduziert werden bei Eigenversickerung.
✓ Math logic verified against primary sources → See our verification process
Kevin Glover
Founder, CalcWolf · GLVTS · Blickr
All formulas sourced from primary references — IRS publications, peer-reviewed research, and official standards. Results are tested against independent reference calculators before publishing. Rates and brackets updated when official sources change. Editorial policy →
🐛 Report a Calculator Error
Found a bug or outdated data? Reports go directly to Kevin and are reviewed personally.