Olean, NY rainwater: 32,325 gallons off a roof
Olean, NY: gallons off the roof each year
32,325gallons a year
That is a 1,500 sq ft asphalt roof under Olean, NY's normal 40.7 inches of rain, about 795 gallons for every inch that falls.
In Olean, NY 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 Olean station (1.1 mi away). Olean, NY ranks 79th wettest of the 90 cities covered in New York.
Month by month in Olean
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 2.73 | 2,170 | |
| Feb | 1.97 | 1,566 | |
| Mar | 2.63 | 2,090 | |
| Apr | 3.35 | 2,663 | 125 |
| May | 3.66 | 2,909 | 86 |
| Jun | 4.48 | 3,561 | |
| Jul | 4.28 | 3,402 | 9 |
| Aug | 4.03 | 3,203 | 40 |
| Sep | 3.85 | 3,060 | 62 |
| Oct | 3.60 | 2,861 | 94 |
| Nov | 2.87 | 2,281 | |
| Dec | 3.22 | 2,559 |
Jun is the wettest month (4.48 in, 3,561 gal off the roof); Feb the driest (1.97 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 Olean
Best fit: one 55-gallon barrel, which delivers about 308 gallons to the garden in a normal year (74.2% 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 Olean's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 308 | 30,651 |
| 110 gal | 308 | 30,651 |
| 165 gal | 308 | 30,651 |
| 275 gal | 308 | 30,651 |
| 550 gal | 308 | 30,651 |
| 1,000 gal | 308 | 30,651 |
| 1,500 gal | 308 | 30,651 |
| 2,500 gal | 308 | 30,651 |
| 5,000 gal | 308 | 30,651 |
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 New York?
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