RoofRainYield

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

How much rain a roof in Lockport, IL collects

32,047gallons a year

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

In Lockport, 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 Lockport 1.3 Se station (1.2 mi away). Lockport, IL ranks 91st wettest of the 225 cities covered in Illinois.

Month by month in Lockport

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan2.141,701
Feb1.941,542
Mar2.792,218
Apr3.873,07660
May4.533,600
Jun4.623,672
Jul4.573,632
Aug4.083,24334
Sep3.322,639128
Oct3.562,83098
Nov2.662,114
Dec2.241,780

Jun is the wettest month (4.62 in, 3,672 gal off the roof); Feb the driest (1.94 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 Lockport?

Best fit: one 55-gallon barrel, which delivers about 252 gallons to the garden in a normal year (78.6% 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 Lockport's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal25230,639
110 gal25230,639
165 gal25230,639
275 gal25230,639
550 gal25230,639
1,000 gal25230,639
1,500 gal25230,639
2,500 gal25230,639
5,000 gal25230,639

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