RoofRainYield

Union City, NJ rainwater: 39,359 gallons off a roof

Rainwater from a roof in Union City, NJ

39,359gallons a year

That is a 1,500 sq ft asphalt roof under Union City, NJ's normal 49.5 inches of rain, about 795 gallons for every inch that falls.

In Union City, NJ 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 New York Cntrl Pk Twr station (3.4 mi away). Union City, NJ ranks 49th wettest of the 116 cities covered in New Jersey.

Month by month in Union City

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan3.642,893
Feb3.192,535
Mar4.293,410
Apr4.093,25132
May3.963,14749
Jun4.543,608
Jul4.603,656
Aug4.563,624
Sep4.313,4265
Oct4.383,481
Nov3.582,845
Dec4.383,481

Jul is the wettest month (4.60 in, 3,656 gal off the roof); Feb the driest (3.19 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 Union City?

Best fit: one 55-gallon barrel, which delivers about 66 gallons to the garden in a normal year (76.7% 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 Union City's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal6638,092
110 gal6638,092
165 gal6638,092
275 gal6638,092
550 gal6638,092
1,000 gal6638,092
1,500 gal6638,092
2,500 gal6638,092
5,000 gal6638,092

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 New Jersey?

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