RoofRainYield

Morris, IL rainwater: 30,830 gallons off a roof

Rainwater from a roof in Morris, IL

30,830gallons a year

That is a 1,500 sq ft asphalt roof under Morris, IL's normal 38.8 inches of rain, about 795 gallons for every inch that falls.

In Morris, 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 Morris 1 Nw station (0.8 mi away). Morris, IL ranks 163rd wettest of the 225 cities covered in Illinois.

Month by month in Morris

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan2.091,661
Feb1.791,423
Mar2.231,772
Apr3.342,655126
May4.393,489
Jun4.723,751
Jul4.923,910
Aug4.013,18742
Sep3.552,822100
Oct3.232,567140
Nov2.501,987
Dec2.021,606

Jul is the wettest month (4.92 in, 3,910 gal off the roof); Feb the driest (1.79 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 Morris

Best fit: one 55-gallon barrel, which delivers about 326 gallons to the garden in a normal year (80.0% 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 Morris's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal32629,439
110 gal32629,439
165 gal32629,439
275 gal32629,439
550 gal32629,439
1,000 gal32629,439
1,500 gal32629,439
2,500 gal32629,439
5,000 gal32629,439

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