RoofRainYield

Mequon, WI rainwater: 28,231 gallons off a roof

Mequon, WI: gallons off the roof each year

28,231gallons a year

That is a 1,500 sq ft asphalt roof under Mequon, WI's normal 35.5 inches of rain, about 795 gallons for every inch that falls.

In Mequon, 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 Germantown 1.3 Ne station (4.6 mi away). Mequon, WI ranks 46th wettest of the 98 cities covered in Wisconsin.

Month by month in Mequon

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan1.541,224
Feb1.571,248
Mar2.431,931
Apr3.642,89389
May3.793,01270
Jun4.553,616
Jul3.772,99672
Aug3.973,15547
Sep3.252,583137
Oct2.852,265187
Nov2.091,661
Dec2.071,645

Jun is the wettest month (4.55 in, 3,616 gal off the roof); Jan the driest (1.54 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 Mequon

Best fit: one 55-gallon barrel, which delivers about 475 gallons to the garden in a normal year (78.9% 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 Mequon's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal47526,721
110 gal47526,721
165 gal47526,721
275 gal47526,721
550 gal47526,721
1,000 gal47526,721
1,500 gal47526,721
2,500 gal47526,721
5,000 gal47526,721

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