Columbus, IN rainwater: 37,626 gallons off a roof
Columbus, IN: gallons off the roof each year
37,626gallons a year
That is a 1,500 sq ft asphalt roof under Columbus, IN's normal 47.3 inches of rain, about 795 gallons for every inch that falls.
In Columbus, IN a single barrel does most of the work. Storms come often enough that a small tank refills before it runs dry, and a bigger one would mostly sit full.
Rainfall: NOAA 1991-2020 climate normals, the Columbus station (2.8 mi away). Columbus, IN ranks 13th wettest of the 88 cities covered in Indiana.
Month by month in Columbus
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.42 | 2,718 | |
| Feb | 2.91 | 2,313 | |
| Mar | 3.78 | 3,004 | |
| Apr | 5.00 | 3,974 | |
| May | 4.99 | 3,966 | |
| Jun | 5.31 | 4,220 | |
| Jul | 4.54 | 3,608 | |
| Aug | 3.48 | 2,766 | 108 |
| Sep | 3.21 | 2,551 | 142 |
| Oct | 3.39 | 2,694 | 120 |
| Nov | 3.60 | 2,861 | |
| Dec | 3.71 | 2,949 |
Jun is the wettest month (5.31 in, 4,220 gal off the roof); Feb the driest (2.91 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.
Which tank size is worth it in Columbus
Best fit: one 55-gallon barrel, which delivers about 306 gallons to the garden in a normal year (82.6% of its need).
If you set one up, a 55-gallon barrel with a downspout diverter is the whole job. Check that the overflow points away from your foundation, because most of Columbus's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 306 | 36,105 |
| 110 gal | 306 | 36,105 |
| 165 gal | 306 | 36,105 |
| 275 gal | 306 | 36,105 |
| 550 gal | 306 | 36,105 |
| 1,000 gal | 306 | 36,105 |
| 1,500 gal | 306 | 36,105 |
| 2,500 gal | 306 | 36,105 |
| 5,000 gal | 306 | 36,105 |
Simulated storm by storm through a normal year using the station's count of days with 0.1 in or more of rain each month.
Is rainwater collection legal in Indiana?
No statewide rainwater harvesting regulations; check county for local incentives
From the 2015 (Pacific Northwest National Laboratory report 24347); not yet re-checked against current law, so check with your state water agency before building anything large. Source