Glenwood Springs, CO rainwater: 15,507 gallons off a roof
Rainwater from a roof in Glenwood Springs, CO
15,507gallons a year
That is a 1,500 sq ft asphalt roof under Glenwood Springs, CO's normal 19.5 inches of rain, about 795 gallons for every inch that falls.
In Glenwood Springs, 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 Glenwood Springs .64 S station (0.9 mi away). Glenwood Springs, CO ranks 5th wettest of the 53 cities covered in Colorado.
Month by month in Glenwood Springs
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 1.62 | 1,288 | |
| Feb | 1.65 | 1,311 | |
| Mar | 1.50 | 1,192 | |
| Apr | 2.03 | 1,613 | 289 |
| May | 2.15 | 1,709 | 274 |
| Jun | 0.96 | 763 | 423 |
| Jul | 1.29 | 1,025 | 382 |
| Aug | 1.45 | 1,152 | 362 |
| Sep | 1.80 | 1,431 | 318 |
| Oct | 2.08 | 1,653 | 283 |
| Nov | 1.55 | 1,232 | |
| Dec | 1.43 | 1,137 |
May is the wettest month (2.15 in, 1,709 gal off the roof); Jun the driest (0.96 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 Glenwood Springs?
Best fit: 2 linked 55-gallon barrels, which delivers about 1,887 gallons to the garden in a normal year (81.0% 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 Glenwood Springs's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 1,520 | 13,147 |
| 110 gal | 1,887 | 12,780 |
| 165 gal (over cap) | 1,983 | 12,684 |
| 275 gal (over cap) | 2,015 | 12,652 |
| 550 gal (over cap) | 2,015 | 12,652 |
| 1,000 gal (over cap) | 2,015 | 12,652 |
| 1,500 gal (over cap) | 2,015 | 12,652 |
| 2,500 gal (over cap) | 2,015 | 12,652 |
| 5,000 gal (over cap) | 2,015 | 12,652 |
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