RoofRainYield

Northlake, IL rainwater: 30,711 gallons off a roof

Rainwater from a roof in Northlake, IL

30,711gallons a year

That is a 1,500 sq ft asphalt roof under Northlake, IL's normal 38.6 inches of rain, about 795 gallons for every inch that falls.

In Northlake, 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 Elmhurst 0.8 Ese station (1.9 mi away). Northlake, IL ranks 177th wettest of the 225 cities covered in Illinois.

Month by month in Northlake

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan1.911,518
Feb1.981,574
Mar2.401,908
Apr3.692,93382
May4.783,799
Jun4.473,553
Jul3.762,98874
Aug4.203,33819
Sep3.222,559141
Oct3.562,83098
Nov2.582,051
Dec2.091,661

May is the wettest month (4.78 in, 3,799 gal off the roof); Jan the driest (1.91 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 Northlake?

Best fit: one 55-gallon barrel, which delivers about 329 gallons to the garden in a normal year (79.5% 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 Northlake's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal32929,287
110 gal32929,287
165 gal32929,287
275 gal32929,287
550 gal32929,287
1,000 gal32929,287
1,500 gal32929,287
2,500 gal32929,287
5,000 gal32929,287

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