Lawrence, IN rainwater: 37,038 gallons off a roof
Rainwater from a roof in Lawrence, IN
37,038gallons a year
That is a 1,500 sq ft asphalt roof under Lawrence, IN's normal 46.6 inches of rain, about 795 gallons for every inch that falls.
In Lawrence, 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 Lawrence 2.0 Ene station (2.2 mi away). Lawrence, IN ranks 18th wettest of the 88 cities covered in Indiana.
Month by month in Lawrence
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.35 | 2,663 | |
| Feb | 2.90 | 2,305 | |
| Mar | 3.48 | 2,766 | |
| Apr | 4.71 | 3,744 | |
| May | 4.89 | 3,887 | |
| Jun | 5.96 | 4,737 | |
| Jul | 4.60 | 3,656 | |
| Aug | 3.65 | 2,901 | 87 |
| Sep | 3.34 | 2,655 | 126 |
| Oct | 3.35 | 2,663 | 125 |
| Nov | 3.62 | 2,877 | |
| Dec | 2.75 | 2,186 |
Jun is the wettest month (5.96 in, 4,737 gal off the roof); Dec the driest (2.75 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.
Barrel or cistern in Lawrence?
Best fit: one 55-gallon barrel, which delivers about 275 gallons to the garden in a normal year (81.4% 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 Lawrence's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 275 | 35,548 |
| 110 gal | 275 | 35,548 |
| 165 gal | 275 | 35,548 |
| 275 gal | 275 | 35,548 |
| 550 gal | 275 | 35,548 |
| 1,000 gal | 275 | 35,548 |
| 1,500 gal | 275 | 35,548 |
| 2,500 gal | 275 | 35,548 |
| 5,000 gal | 275 | 35,548 |
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