Golden, CO rainwater: 16,492 gallons off a roof
Golden, CO: gallons off the roof each year
16,492gallons a year
That is a 1,500 sq ft asphalt roof under Golden, CO's normal 20.8 inches of rain, about 795 gallons for every inch that falls.
In Golden, 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 Golden 1.2 Nw station (2.2 mi away). Golden, CO ranks 2nd wettest of the 53 cities covered in Colorado.
Month by month in Golden
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.73 | 580 | |
| Feb | 0.93 | 739 | |
| Mar | 1.79 | 1,423 | |
| Apr | 2.95 | 2,345 | 175 |
| May | 2.84 | 2,257 | 188 |
| Jun | 2.38 | 1,892 | 246 |
| Jul | 2.10 | 1,669 | 281 |
| Aug | 2.13 | 1,693 | 277 |
| Sep | 1.54 | 1,224 | 350 |
| Oct | 1.46 | 1,160 | 360 |
| Nov | 1.03 | 819 | |
| Dec | 0.87 | 691 |
Apr is the wettest month (2.95 in, 2,345 gal off the roof); Jan the driest (0.73 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 Golden
Best fit: 2 linked 55-gallon barrels, which delivers about 1,562 gallons to the garden in a normal year (83.2% 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 Golden's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 1,388 | 14,264 |
| 110 gal | 1,562 | 14,090 |
| 165 gal (over cap) | 1,562 | 14,090 |
| 275 gal (over cap) | 1,562 | 14,090 |
| 550 gal (over cap) | 1,562 | 14,090 |
| 1,000 gal (over cap) | 1,562 | 14,090 |
| 1,500 gal (over cap) | 1,562 | 14,090 |
| 2,500 gal (over cap) | 1,562 | 14,090 |
| 5,000 gal (over cap) | 1,562 | 14,090 |
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