RoofRainYield

Cudahy, WI rainwater: 27,476 gallons off a roof

Cudahy, WI: gallons off the roof each year

27,476gallons a year

That is a 1,500 sq ft asphalt roof under Cudahy, WI's normal 34.6 inches of rain, about 795 gallons for every inch that falls.

In Cudahy, WI 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 Milwaukee Mitchell Ap station (2.1 mi away). Cudahy, WI ranks 61st wettest of the 98 cities covered in Wisconsin.

Month by month in Cudahy

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan1.791,423
Feb1.691,343
Mar2.201,749
Apr3.863,06861
May3.542,814101
Jun4.383,481
Jul3.402,702118
Aug3.652,90187
Sep3.162,512148
Oct2.782,210196
Nov2.241,780
Dec1.881,494

Jun is the wettest month (4.38 in, 3,481 gal off the roof); Feb the driest (1.69 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 Cudahy

Best fit: one 55-gallon barrel, which delivers about 572 gallons to the garden in a normal year (80.3% 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 Cudahy's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal57225,884
110 gal57225,884
165 gal57225,884
275 gal57225,884
550 gal57225,884
1,000 gal57225,884
1,500 gal57225,884
2,500 gal57225,884
5,000 gal57225,884

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 Wisconsin?

No rainwater harvesting regulations

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