RoofRainYield

Newport News, VA rainwater: 40,805 gallons off a roof

Rainwater from a roof in Newport News, VA

40,805gallons a year

That is a 1,500 sq ft asphalt roof under Newport News, VA's normal 51.3 inches of rain, about 795 gallons for every inch that falls.

In Newport News, 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 Newport News 3.3 E station (3.7 mi away). Newport News, VA ranks 4th wettest of the 39 cities covered in Virginia.

Month by month in Newport News

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan3.472,758
Feb2.862,273
Mar3.692,933
Apr3.202,543143
May4.533,600
Jun4.893,887
Jul4.913,902
Aug6.204,928
Sep5.314,220
Oct5.144,085
Nov3.612,869
Dec3.532,806

Aug is the wettest month (6.20 in, 4,928 gal off the roof); Feb the driest (2.86 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.

Barrel or cistern in Newport News?

Best fit: one 55-gallon barrel, which delivers about 115 gallons to the garden in a normal year (80.2% 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 Newport News's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal11539,401
110 gal11539,401
165 gal11539,401
275 gal11539,401
550 gal11539,401
1,000 gal11539,401
1,500 gal11539,401
2,500 gal11539,401
5,000 gal11539,401

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