Easton, MD rainwater: 37,904 gallons off a roof
Easton, MD: gallons off the roof each year
37,904gallons a year
That is a 1,500 sq ft asphalt roof under Easton, MD's normal 47.7 inches of rain, about 795 gallons for every inch that falls.
In Easton, MD 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 Easton 2.4 Se station (2.5 mi away). Easton, MD ranks 4th wettest of the 23 cities covered in Maryland.
Month by month in Easton
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.28 | 2,607 | |
| Feb | 2.96 | 2,353 | |
| Mar | 3.90 | 3,100 | |
| Apr | 3.55 | 2,822 | 100 |
| May | 4.34 | 3,449 | 1 |
| Jun | 3.97 | 3,155 | 47 |
| Jul | 4.41 | 3,505 | |
| Aug | 5.10 | 4,054 | |
| Sep | 4.43 | 3,521 | |
| Oct | 4.39 | 3,489 | |
| Nov | 3.29 | 2,615 | |
| Dec | 4.07 | 3,235 |
Aug is the wettest month (5.10 in, 4,054 gal off the roof); Feb the driest (2.96 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 Easton
Best fit: one 55-gallon barrel, which delivers about 114 gallons to the garden in a normal year (76.8% 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 Easton's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 114 | 36,606 |
| 110 gal | 114 | 36,606 |
| 165 gal | 114 | 36,606 |
| 275 gal | 114 | 36,606 |
| 550 gal | 114 | 36,606 |
| 1,000 gal | 114 | 36,606 |
| 1,500 gal | 114 | 36,606 |
| 2,500 gal | 114 | 36,606 |
| 5,000 gal | 114 | 36,606 |
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 Maryland?
No statewide rainwater harvesting regulations; check county for local incentives
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