RoofRainYield

Charlottesville, VA rainwater: 38,572 gallons off a roof

Rainwater from a roof in Charlottesville, VA

38,572gallons a year

That is a 1,500 sq ft asphalt roof under Charlottesville, VA's normal 48.5 inches of rain, about 795 gallons for every inch that falls.

In Charlottesville, VA 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 Charlottesville 2w station (2.0 mi away). Charlottesville, VA ranks 8th wettest of the 39 cities covered in Virginia.

Month by month in Charlottesville

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan3.422,718
Feb2.972,361
Mar3.963,147
Apr3.482,766108
May4.633,680
Jun4.683,720
Jul4.843,847
Aug4.023,19541
Sep5.214,141
Oct3.923,11654
Nov3.652,901
Dec3.752,981

Sep is the wettest month (5.21 in, 4,141 gal off the roof); Feb the driest (2.97 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 Charlottesville

Best fit: one 55-gallon barrel, which delivers about 161 gallons to the garden in a normal year (79.2% 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 Charlottesville's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal16137,241
110 gal16137,241
165 gal16137,241
275 gal16137,241
550 gal16137,241
1,000 gal16137,241
1,500 gal16137,241
2,500 gal16137,241
5,000 gal16137,241

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 Virginia?

Legal and promoted by the state. Va. Code 32.1-248.2 directs the Board of Health to set standards for rainwater harvesting systems, and the Department of Health with DEQ to promote rainwater use. No state storage cap; indoor/potable use must meet health regulations.

Checked against the current source on 2026-11-06. Source