RoofRainYield

Hendersonville, NC rainwater: 46,933 gallons off a roof

Hendersonville, NC: gallons off the roof each year

46,933gallons a year

That is a 1,500 sq ft asphalt roof under Hendersonville, NC's normal 59.1 inches of rain, about 795 gallons for every inch that falls.

In Hendersonville, 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 Hendersonville 1 Ne station (0.5 mi away). Hendersonville, NC ranks 4th wettest of the 91 cities covered in North Carolina.

Month by month in Hendersonville

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan5.284,197
Feb4.263,386
Mar4.953,934
Apr4.843,847
May4.403,497
Jun4.953,934
Jul5.794,602
Aug5.734,554
Sep4.973,950
Oct4.063,22736
Nov4.553,616
Dec5.274,189

Jul is the wettest month (5.79 in, 4,602 gal off the roof); Oct the driest (4.06 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 Hendersonville

Best fit: one 55-gallon barrel, which delivers about 30 gallons to the garden in a normal year (83.0% 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 Hendersonville's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal3045,583
110 gal3045,583
165 gal3045,583
275 gal3045,583
550 gal3045,583
1,000 gal3045,583
1,500 gal3045,583
2,500 gal3045,583
5,000 gal3045,583

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