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Calculate Gutter Size for Your Roof

Size gutters and downspouts based on roof area and rainfall intensity. Prevent overflow and foundation damage.

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

India

Monsoon drainage critical। Flat roofs need proper slope (1:100 minimum)। Downpipes: 1 per 10-12m gutter। Many Indian homes lack proper rainwater drainage — causes wall damage, seepage, foundation issues।

Rainwater Harvesting

Mandatory: Chennai, Bangalore, Delhi, Hyderabad। Gutter → filter → storage/recharge pit। Saves water + may reduce water bill + legally required in many cities।

⚡ CalcWolf Insight

Foundation damage from poor drainage costs $5,000-30,000 to repair. Properly sized gutters and downspouts with extensions cost $1,500-3,000 installed. This is one of the highest-ROI home improvements — protecting your foundation protects your largest investment. Check your gutters during the next heavy rain and note any overflow points.

Frequently asked questions
Mandatory?▾
Many Indian cities: yes। Chennai pioneered mandatory rainwater harvesting।
Cost?▾
Basic system: ₹5,000-15,000। Saves water bill + legal compliance।
✓ 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 →
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