RoofRainYield

Worth, IL rainwater: 32,047 gallons off a roof

Rainwater from a roof in Worth, IL

32,047gallons a year

That is a 1,500 sq ft asphalt roof under Worth, IL's normal 40.3 inches of rain, about 795 gallons for every inch that falls.

In Worth, IL 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 Oak Lawn 1.6 Wnw station (2.8 mi away). Worth, IL ranks 96th wettest of the 225 cities covered in Illinois.

Month by month in Worth

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan2.231,772
Feb2.111,677
Mar2.532,011
Apr3.973,15547
May4.733,759
Jun4.403,497
Jul4.283,4029
Aug4.163,30624
Sep3.462,750111
Oct3.492,774107
Nov2.762,194
Dec2.201,749

May is the wettest month (4.73 in, 3,759 gal off the roof); Feb the driest (2.11 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 Worth?

Best fit: one 55-gallon barrel, which delivers about 232 gallons to the garden in a normal year (77.9% 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 Worth's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal23230,645
110 gal23230,645
165 gal23230,645
275 gal23230,645
550 gal23230,645
1,000 gal23230,645
1,500 gal23230,645
2,500 gal23230,645
5,000 gal23230,645

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 Illinois?

Local government can regulate rainwater harvesting per state plumbing law

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