Greenwood Village, CO rainwater: 14,259 gallons off a roof
How much rain a roof in Greenwood Village, CO collects
14,259gallons a year
That is a 1,500 sq ft asphalt roof under Greenwood Village, CO's normal 17.9 inches of rain, about 795 gallons for every inch that falls.
In Greenwood Village, CO 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 Centennial 3.7 W station (1.5 mi away). Greenwood Village, CO ranks 16th wettest of the 53 cities covered in Colorado.
Month by month in Greenwood Village
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.62 | 493 | |
| Feb | 0.75 | 596 | |
| Mar | 1.57 | 1,248 | |
| Apr | 2.22 | 1,764 | 266 |
| May | 2.36 | 1,876 | 248 |
| Jun | 1.96 | 1,558 | 298 |
| Jul | 2.17 | 1,725 | 272 |
| Aug | 1.99 | 1,582 | 294 |
| Sep | 1.61 | 1,280 | 342 |
| Oct | 1.26 | 1,001 | 385 |
| Nov | 0.83 | 660 | |
| Dec | 0.60 | 477 |
May is the wettest month (2.36 in, 1,876 gal off the roof); Dec the driest (0.60 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 Greenwood Village?
Best fit: 2 linked 55-gallon barrels, which delivers about 1,815 gallons to the garden in a normal year (86.2% of its need).
If you buy one, a 55-gallon barrel with a downspout diverter is the whole job. Check that the overflow points away from your foundation, because most of Greenwood Village's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 1,497 | 12,132 |
| 110 gal | 1,815 | 11,814 |
| 165 gal (over cap) | 1,815 | 11,814 |
| 275 gal (over cap) | 1,815 | 11,814 |
| 550 gal (over cap) | 1,815 | 11,814 |
| 1,000 gal (over cap) | 1,815 | 11,814 |
| 1,500 gal (over cap) | 1,815 | 11,814 |
| 2,500 gal (over cap) | 1,815 | 11,814 |
| 5,000 gal (over cap) | 1,815 | 11,814 |
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 Colorado?
Most households may use rain barrels: a maximum of two rain barrels with a combined storage of 110 gallons or less per household, rooftop runoff only, used outdoors on the same property (HB16-1005). Larger rooftop collection only for qualifying well-permit holders (SB09-080) or pilot projects (HB09-1129).
Checked against the current source on 2026-11-06. Source