RoofRainYield

Kings Mountain, NC rainwater: 35,250 gallons off a roof

How much rain a roof in Kings Mountain, NC collects

35,250gallons a year

That is a 1,500 sq ft asphalt roof under Kings Mountain, NC's normal 44.4 inches of rain, about 795 gallons for every inch that falls.

In Kings Mountain, NC 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 Gastonia 1.8 Sse station (10.8 mi away). Kings Mountain, NC ranks 80th wettest of the 91 cities covered in North Carolina.

Month by month in Kings Mountain

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan3.602,861
Feb3.212,551
Mar3.923,116
Apr3.913,10855
May3.482,766108
Jun4.383,481
Jul3.772,99672
Aug4.093,25132
Sep3.582,84596
Oct3.252,583137
Nov3.282,607
Dec3.883,084

Jun is the wettest month (4.38 in, 3,481 gal off the roof); Feb the driest (3.21 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 Kings Mountain

Best fit: one 55-gallon barrel, which delivers about 411 gallons to the garden in a normal year (82.0% of its need).

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

TankWater used (gal/yr)Spills over (gal/yr)
55 gal41133,774
110 gal41133,774
165 gal41133,774
275 gal41133,774
550 gal41133,774
1,000 gal41133,774
1,500 gal41133,774
2,500 gal41133,774
5,000 gal41133,774

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 North Carolina?

Regulated through the Department of Environment and Natural Resources; allowed through state’s plumbing code; 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