Arvada, CO rainwater: 14,251 gallons off a roof
How much rain a roof in Arvada, CO collects
14,251gallons a year
That is a 1,500 sq ft asphalt roof under Arvada, CO's normal 17.9 inches of rain, about 795 gallons for every inch that falls.
In Arvada, 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 Arvada 3.5 Wnw station (1.2 mi away). Arvada, CO ranks 17th wettest of the 53 cities covered in Colorado.
Month by month in Arvada
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.68 | 540 | |
| Feb | 0.80 | 636 | |
| Mar | 1.61 | 1,280 | |
| Apr | 2.45 | 1,947 | 237 |
| May | 2.82 | 2,241 | 191 |
| Jun | 1.75 | 1,391 | 324 |
| Jul | 1.82 | 1,447 | 315 |
| Aug | 1.68 | 1,335 | 333 |
| Sep | 1.47 | 1,168 | 359 |
| Oct | 1.28 | 1,017 | 383 |
| Nov | 0.91 | 723 | |
| Dec | 0.66 | 525 |
May is the wettest month (2.82 in, 2,241 gal off the roof); Dec the driest (0.66 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 Arvada?
Best fit: 2 linked 55-gallon barrels, which delivers about 1,854 gallons to the garden in a normal year (86.6% 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 Arvada's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 1,404 | 12,201 |
| 110 gal | 1,854 | 11,752 |
| 165 gal (over cap) | 1,854 | 11,752 |
| 275 gal (over cap) | 1,854 | 11,752 |
| 550 gal (over cap) | 1,854 | 11,752 |
| 1,000 gal (over cap) | 1,854 | 11,752 |
| 1,500 gal (over cap) | 1,854 | 11,752 |
| 2,500 gal (over cap) | 1,854 | 11,752 |
| 5,000 gal (over cap) | 1,854 | 11,752 |
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