RoofRainYield

Port Washington, WI rainwater: 27,810 gallons off a roof

How much rain a roof in Port Washington, WI collects

27,810gallons a year

That is a 1,500 sq ft asphalt roof under Port Washington, WI's normal 35.0 inches of rain, about 795 gallons for every inch that falls.

In Port Washington, 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 Port Washington 0.5 S station (0.3 mi away). Port Washington, WI ranks 58th wettest of the 98 cities covered in Wisconsin.

Month by month in Port Washington

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan1.791,423
Feb1.581,256
Mar1.971,566
Apr3.943,13251
May3.762,98874
Jun4.453,537
Jul3.813,02867
Aug3.712,94980
Sep3.012,392167
Oct2.742,178201
Nov2.081,653
Dec2.151,709

Jun is the wettest month (4.45 in, 3,537 gal off the roof); Feb 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.

Barrel or cistern in Port Washington?

Best fit: one 55-gallon barrel, which delivers about 522 gallons to the garden in a normal year (81.6% 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 Port Washington's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal52226,298
110 gal52226,298
165 gal52226,298
275 gal52226,298
550 gal52226,298
1,000 gal52226,298
1,500 gal52226,298
2,500 gal52226,298
5,000 gal52226,298

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