雨水收集计算器
使用雨水收集计算器评估屋顶或场地的雨水收集潜力。输入集水面积和当地降水量，计算年度可收集雨水量，规划储水系统容量，减少自来水消耗。
Annual Rainwater Collected
29,904 gallons
Annual Rainwater Collected vs Collection Roof Area
公式
How to Calculate Rainwater Collection
Rainwater harvesting captures roof runoff for irrigation, toilet flushing, or other non-potable uses.
Formula
Gallons = Roof Area (sq ft) * Rainfall (inches) * 0.623 * Collection Efficiency
The factor 0.623 converts 1 inch of rain on 1 sq ft to gallons. Efficiency accounts for gutter losses, first-flush diversion, and evaporation.
计算示例
1,500 sq ft roof in an area with 40 inches annual rainfall, 80% collection efficiency, $5/1000 gal water cost.
- 01Annual collection: 1,500 * 40 * 0.623 * 0.80 = 29,904 gallons
- 02Monthly average: 29,904 / 12 = 2,492 gallons
- 03Annual savings: 29,904 * $5 / 1,000 = $150
- 04Recommended tank: ceil(2,492 / 100) * 100 = 2,500 gallons
常见问题
Is rainwater harvesting legal?
Most US states allow rainwater harvesting. Some states like Texas and Oregon actively encourage it with tax incentives. A few arid states have restrictions, so check local regulations.
How much rain can I collect from 1,000 sq ft?
One inch of rain on 1,000 sq ft yields about 623 gallons. At 80% efficiency, that is about 498 usable gallons per inch of rainfall.
Can I drink collected rainwater?
Rainwater can be made potable with proper filtration and UV/chemical treatment, but most residential systems use it for irrigation, toilet flushing, and laundry.