Franklin, IN rainwater: 35,742 gallons off a roof
Rainwater from a roof in Franklin, IN
35,742gallons a year
That is a 1,500 sq ft asphalt roof under Franklin, IN's normal 45.0 inches of rain, about 795 gallons for every inch that falls.
In Franklin, 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 Franklin 1 W station (1.3 mi away). Franklin, IN ranks 25th wettest of the 88 cities covered in Indiana.
Month by month in Franklin
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.22 | 2,559 | |
| Feb | 2.42 | 1,923 | |
| Mar | 3.60 | 2,861 | |
| Apr | 4.80 | 3,815 | |
| May | 4.99 | 3,966 | |
| Jun | 5.08 | 4,038 | |
| Jul | 4.37 | 3,473 | |
| Aug | 3.39 | 2,694 | 120 |
| Sep | 3.27 | 2,599 | 135 |
| Oct | 3.11 | 2,472 | 155 |
| Nov | 3.56 | 2,830 | |
| Dec | 3.16 | 2,512 |
Jun is the wettest month (5.08 in, 4,038 gal off the roof); Feb the driest (2.42 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.
What size rain barrel for Franklin
Best fit: one 55-gallon barrel, which delivers about 337 gallons to the garden in a normal year (82.4% of its need).
Before you buy, a 55-gallon barrel with a downspout diverter is the whole job. Check that the overflow points away from your foundation, because most of Franklin's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 337 | 34,190 |
| 110 gal | 337 | 34,190 |
| 165 gal | 337 | 34,190 |
| 275 gal | 337 | 34,190 |
| 550 gal | 337 | 34,190 |
| 1,000 gal | 337 | 34,190 |
| 1,500 gal | 337 | 34,190 |
| 2,500 gal | 337 | 34,190 |
| 5,000 gal | 337 | 34,190 |
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