Merrillville, IN rainwater: 32,492 gallons off a roof
Merrillville, IN: gallons off the roof each year
32,492gallons a year
That is a 1,500 sq ft asphalt roof under Merrillville, IN's normal 40.9 inches of rain, about 795 gallons for every inch that falls.
In Merrillville, 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 Crown Pt 1n station (3.0 mi away). Merrillville, IN ranks 58th wettest of the 88 cities covered in Indiana.
Month by month in Merrillville
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 2.49 | 1,979 | |
| Feb | 2.00 | 1,590 | |
| Mar | 2.29 | 1,820 | |
| Apr | 3.70 | 2,941 | 81 |
| May | 4.33 | 3,442 | 2 |
| Jun | 4.68 | 3,720 | |
| Jul | 4.17 | 3,314 | 22 |
| Aug | 5.22 | 4,149 | |
| Sep | 3.48 | 2,766 | 108 |
| Oct | 3.54 | 2,814 | 101 |
| Nov | 2.75 | 2,186 | |
| Dec | 2.23 | 1,772 |
Aug is the wettest month (5.22 in, 4,149 gal off the roof); Feb the driest (2.00 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 Merrillville
Best fit: one 55-gallon barrel, which delivers about 246 gallons to the garden in a normal year (78.0% 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 Merrillville's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 246 | 31,090 |
| 110 gal | 246 | 31,090 |
| 165 gal | 246 | 31,090 |
| 275 gal | 246 | 31,090 |
| 550 gal | 246 | 31,090 |
| 1,000 gal | 246 | 31,090 |
| 1,500 gal | 246 | 31,090 |
| 2,500 gal | 246 | 31,090 |
| 5,000 gal | 246 | 31,090 |
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