RoofRainYield

Moody, AL rainwater: 45,566 gallons off a roof

Moody, AL: gallons off the roof each year

45,566gallons a year

That is a 1,500 sq ft asphalt roof under Moody, AL's normal 57.3 inches of rain, about 795 gallons for every inch that falls.

In Moody, AL 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 Moody 2.0 Ese station (2.2 mi away). Moody, AL ranks 40th wettest of the 66 cities covered in Alabama.

Month by month in Moody

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan4.863,863
Feb5.584,435
Mar5.514,379
Apr5.554,411
May4.703,736
Jun4.763,783
Jul4.603,656
Aug4.273,39410
Sep4.083,24334
Oct3.552,822100
Nov4.643,688
Dec5.234,157

Feb is the wettest month (5.58 in, 4,435 gal off the roof); Oct the driest (3.55 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 Moody

Best fit: one 55-gallon barrel, which delivers about 124 gallons to the garden in a normal year (86.5% 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 Moody's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal12444,332
110 gal12444,332
165 gal12444,332
275 gal12444,332
550 gal12444,332
1,000 gal12444,332
1,500 gal12444,332
2,500 gal12444,332
5,000 gal12444,332

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 Alabama?

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