Harrison, AR rainwater: 35,369 gallons off a roof

Harrison, AR: gallons off the roof each year

35,369gallons a year

That is a 1,500 sq ft asphalt roof under Harrison, AR's normal 44.5 inches of rain, about 795 gallons for every inch that falls.

In Harrison, AR 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 Harrison Boone Co Ap station (2.7 mi away). Harrison, AR ranks 39th wettest of the 39 cities covered in Arkansas.

Month by month in Harrison

Month	Rain (in)	Off the roof (gal)	Garden shortfall (gal)
Jan	2.67	2,122
Feb	2.42	1,923
Mar	3.91	3,108
Apr	4.98	3,958
May	4.81	3,823
Jun	3.85	3,060	62
Jul	3.67	2,917	85
Aug	3.42	2,718	116
Sep	4.06	3,227	36
Oct	3.81	3,028	67
Nov	3.96	3,147
Dec	2.94	2,337

Apr is the wettest month (4.98 in, 3,958 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.

Which tank size is worth it in Harrison

Best fit: one 55-gallon barrel, which delivers about 298 gallons to the garden in a normal year (81.3% of its need).

If you buy one, a 55-gallon barrel with a downspout diverter is the whole job. Check that the overflow points away from your foundation, because most of Harrison's roof water will pass straight through it.

Tank	Water used (gal/yr)	Spills over (gal/yr)
55 gal	298	33,991
110 gal	298	33,991
165 gal	298	33,991
275 gal	298	33,991
550 gal	298	33,991
1,000 gal	298	33,991
1,500 gal	298	33,991
2,500 gal	298	33,991
5,000 gal	298	33,991

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 Arkansas?

No rainwater harvesting regulations

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