RoofRainYield

New Britain, CT rainwater: 38,167 gallons off a roof

New Britain, CT: gallons off the roof each year

38,167gallons a year

That is a 1,500 sq ft asphalt roof under New Britain, CT's normal 48.0 inches of rain, about 795 gallons for every inch that falls.

In New Britain, CT 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 Newington 1.9 Ssw station (2.6 mi away). New Britain, CT ranks 14th wettest of the 21 cities covered in Connecticut.

Month by month in New Britain

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan3.282,607
Feb2.952,345
Mar4.163,306
Apr4.563,624
May3.662,90986
Jun4.523,593
Jul3.722,95779
Aug4.243,37014
Sep4.163,30624
Oct4.553,616
Nov3.793,012
Dec4.433,521

Apr is the wettest month (4.56 in, 3,624 gal off the roof); Feb the driest (2.95 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 New Britain

Best fit: one 55-gallon barrel, which delivers about 158 gallons to the garden in a normal year (78.2% 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 New Britain's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal15836,868
110 gal15836,868
165 gal15836,868
275 gal15836,868
550 gal15836,868
1,000 gal15836,868
1,500 gal15836,868
2,500 gal15836,868
5,000 gal15836,868

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 Connecticut?

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