Cedarburg, WI rainwater: 28,224 gallons off a roof

Cedarburg, WI: gallons off the roof each year

28,224gallons a year

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

In Cedarburg, 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 Grafton Wwtp station (1.8 mi away). Cedarburg, WI ranks 47th wettest of the 98 cities covered in Wisconsin.

Month by month in Cedarburg

Month	Rain (in)	Off the roof (gal)	Garden shortfall (gal)
Jan	1.58	1,256
Feb	1.73	1,375
Mar	2.07	1,645
Apr	3.94	3,132	51
May	3.99	3,171	45
Jun	4.50	3,577
Jul	3.61	2,869	92
Aug	3.77	2,996	72
Sep	3.18	2,527	146
Oct	2.98	2,369	171
Nov	2.15	1,709
Dec	2.01	1,598

Jun is the wettest month (4.50 in, 3,577 gal off the roof); Jan the driest (1.58 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.

Which tank size is worth it in Cedarburg

Best fit: one 55-gallon barrel, which delivers about 443 gallons to the garden in a normal year (76.7% 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 Cedarburg's roof water will pass straight through it.

Tank	Water used (gal/yr)	Spills over (gal/yr)
55 gal	443	26,640
110 gal	443	26,640
165 gal	443	26,640
275 gal	443	26,640
550 gal	443	26,640
1,000 gal	443	26,640
1,500 gal	443	26,640
2,500 gal	443	26,640
5,000 gal	443	26,640

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