Carmel, IN rainwater: 35,099 gallons off a roof
Carmel, IN: gallons off the roof each year
35,099gallons a year
That is a 1,500 sq ft asphalt roof under Carmel, IN's normal 44.2 inches of rain, about 795 gallons for every inch that falls.
In Carmel, 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 Carmel 1.5 W station (0.6 mi away). Carmel, IN ranks 33rd wettest of the 88 cities covered in Indiana.
Month by month in Carmel
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 2.96 | 2,353 | |
| Feb | 2.44 | 1,939 | |
| Mar | 3.57 | 2,837 | |
| Apr | 4.26 | 3,386 | 11 |
| May | 4.74 | 3,767 | |
| Jun | 5.09 | 4,046 | |
| Jul | 4.24 | 3,370 | 14 |
| Aug | 3.59 | 2,853 | 95 |
| Sep | 3.41 | 2,710 | 117 |
| Oct | 3.27 | 2,599 | 135 |
| Nov | 3.61 | 2,869 | |
| Dec | 2.98 | 2,369 |
Jun is the wettest month (5.09 in, 4,046 gal off the roof); Feb the driest (2.44 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 Carmel
Best fit: one 55-gallon barrel, which delivers about 302 gallons to the garden in a normal year (81.3% 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 Carmel's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 302 | 33,612 |
| 110 gal | 302 | 33,612 |
| 165 gal | 302 | 33,612 |
| 275 gal | 302 | 33,612 |
| 550 gal | 302 | 33,612 |
| 1,000 gal | 302 | 33,612 |
| 1,500 gal | 302 | 33,612 |
| 2,500 gal | 302 | 33,612 |
| 5,000 gal | 302 | 33,612 |
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