Rain Barrel Calculator
Calculate how much rainwater you can collect from your roof. Estimate water bill savings, garden coverage, and optimal barrel count with US city rainfall data.
| City | Annual (in) | Collection (gal) | Savings/yr |
|---|---|---|---|
| Seattle, WA | 37" | 22,129 | $110.64 |
| Portland, OR | 43" | 25,717 | $128.59 |
| Atlanta, GA | 50" | 29,904 | $149.52 |
| Houston, TX | 50" | 29,904 | $149.52 |
| Denver, CO | 14" | 8,373 | $41.87 |
| Phoenix, AZ | 8" | 4,785 | $23.92 |
| New York, NY | 50" | 29,904 | $149.52 |
| Chicago, IL | 36" | 21,531 | $107.65 |
How to Use Rain Barrel Calculator
- 1Enter roof collection area
- 2Set annual rainfall inches
- 3Choose barrel size and count
- 4View collection and savings
Frequently Asked Questions
How much water can I collect from my roof?▾
1 inch of rain on 1,000 sqft of roof produces about 623 gallons. A 1,200 sqft roof with 40 inches of annual rainfall can collect nearly 30,000 gallons per year.
How many rain barrels do I need?▾
A 55-gallon barrel fills quickly — a 1,000 sqft roof fills it with just 0.1 inches of rain. For meaningful storage, consider 2-4 barrels or a 250-gallon cistern.
Is it legal to collect rainwater?▾
Rainwater collection is legal in most US states. Some states had restrictions but now allow up to 110 gallons. Check your state and local regulations.
About Rain Barrel Calculator
Calculate how much rainwater you can collect from your roof. Estimate water bill savings, garden coverage, and optimal barrel count with US city rainfall data.
NexTool's Rain Barrel Calculator is completely free to use with no sign-up required. Your data is processed directly in your browser and never sent to our servers, ensuring complete privacy and instant results.
Related Tools
Stay Updated
Get notified about new tools, features, and exclusive deals. No spam, ever.