RoofRainYield

Peoria, IL rainwater: 31,578 gallons off a roof

How much rain a roof in Peoria, IL collects

31,578gallons a year

That is a 1,500 sq ft asphalt roof under Peoria, IL's normal 39.7 inches of rain, about 795 gallons for every inch that falls.

In Peoria, 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 Peoria 5nw station (0.2 mi away). Peoria, IL ranks 125th wettest of the 225 cities covered in Illinois.

Month by month in Peoria

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan2.061,637
Feb1.881,494
Mar2.572,043
Apr3.923,11654
May4.513,585
Jun4.703,736
Jul3.762,98874
Aug3.352,663125
Sep4.393,489
Oct3.462,750111
Nov2.922,321
Dec2.211,757

Jun is the wettest month (4.70 in, 3,736 gal off the roof); Feb the driest (1.88 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 Peoria?

Best fit: one 55-gallon barrel, which delivers about 283 gallons to the garden in a normal year (78.0% 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 Peoria's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal28330,125
110 gal28330,125
165 gal28330,125
275 gal28330,125
550 gal28330,125
1,000 gal28330,125
1,500 gal28330,125
2,500 gal28330,125
5,000 gal28330,125

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