RoofRainYield

Taunton, MA rainwater: 38,763 gallons off a roof

Taunton, MA: gallons off the roof each year

38,763gallons a year

That is a 1,500 sq ft asphalt roof under Taunton, MA's normal 48.8 inches of rain, about 795 gallons for every inch that falls.

In Taunton, MA 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 Taunton station (1.5 mi away). Taunton, MA ranks 36th wettest of the 58 cities covered in Massachusetts.

Month by month in Taunton

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan3.722,957
Feb3.432,726
Mar5.054,014
Apr4.753,775
May3.382,686121
Jun4.083,24334
Jul3.502,782106
Aug3.612,86992
Sep3.883,08459
Oct4.283,4029
Nov4.153,298
Dec4.943,926

Mar is the wettest month (5.05 in, 4,014 gal off the roof); May the driest (3.38 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 Taunton?

Best fit: one 55-gallon barrel, which delivers about 326 gallons to the garden in a normal year (77.6% 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 Taunton's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal32637,222
110 gal32637,222
165 gal32637,222
275 gal32637,222
550 gal32637,222
1,000 gal32637,222
1,500 gal32637,222
2,500 gal32637,222
5,000 gal32637,222

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 Massachusetts?

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