Aurora, CO rainwater: 13,941 gallons off a roof
Aurora, CO: gallons off the roof each year
13,941gallons a year
That is a 1,500 sq ft asphalt roof under Aurora, CO's normal 17.5 inches of rain, about 795 gallons for every inch that falls.
In Aurora, 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 Aurora 2.1 Ese station (3.2 mi away). Aurora, CO ranks 21st wettest of the 53 cities covered in Colorado.
Month by month in Aurora
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.58 | 461 | |
| Feb | 0.64 | 509 | |
| Mar | 1.83 | 1,454 | |
| Apr | 2.16 | 1,717 | 273 |
| May | 2.26 | 1,796 | 261 |
| Jun | 1.93 | 1,534 | 302 |
| Jul | 2.17 | 1,725 | 272 |
| Aug | 2.05 | 1,629 | 287 |
| Sep | 1.38 | 1,097 | 370 |
| Oct | 1.20 | 954 | 393 |
| Nov | 0.78 | 620 | |
| Dec | 0.56 | 445 |
May is the wettest month (2.26 in, 1,796 gal off the roof); Dec the driest (0.56 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 Aurora
Best fit: 2 linked 55-gallon barrels, which delivers about 1,878 gallons to the garden in a normal year (87.1% 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 Aurora's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 1,457 | 11,914 |
| 110 gal | 1,878 | 11,493 |
| 165 gal (over cap) | 1,891 | 11,480 |
| 275 gal (over cap) | 1,891 | 11,480 |
| 550 gal (over cap) | 1,891 | 11,480 |
| 1,000 gal (over cap) | 1,891 | 11,480 |
| 1,500 gal (over cap) | 1,891 | 11,480 |
| 2,500 gal (over cap) | 1,891 | 11,480 |
| 5,000 gal (over cap) | 1,891 | 11,480 |
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