Broomfield, CO rainwater: 14,148 gallons off a roof
Rainwater from a roof in Broomfield, CO
14,148gallons a year
That is a 1,500 sq ft asphalt roof under Broomfield, CO's normal 17.8 inches of rain, about 795 gallons for every inch that falls.
In Broomfield, 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 Broomfield 0.9 Ssw station (1.8 mi away). Broomfield, CO ranks 18th wettest of the 53 cities covered in Colorado.
Month by month in Broomfield
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.69 | 548 | |
| Feb | 0.62 | 493 | |
| Mar | 1.63 | 1,296 | |
| Apr | 2.19 | 1,741 | 269 |
| May | 2.53 | 2,011 | 227 |
| Jun | 2.08 | 1,653 | 283 |
| Jul | 2.00 | 1,590 | 293 |
| Aug | 1.55 | 1,232 | 349 |
| Sep | 1.82 | 1,447 | 315 |
| Oct | 1.24 | 986 | 388 |
| Nov | 0.83 | 660 | |
| Dec | 0.62 | 493 |
May is the wettest month (2.53 in, 2,011 gal off the roof); Feb the driest (0.62 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 Broomfield?
Best fit: 2 linked 55-gallon barrels, which delivers about 1,843 gallons to the garden in a normal year (86.8% 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 Broomfield's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 1,420 | 12,112 |
| 110 gal | 1,843 | 11,690 |
| 165 gal (over cap) | 1,843 | 11,690 |
| 275 gal (over cap) | 1,843 | 11,690 |
| 550 gal (over cap) | 1,843 | 11,690 |
| 1,000 gal (over cap) | 1,843 | 11,690 |
| 1,500 gal (over cap) | 1,843 | 11,690 |
| 2,500 gal (over cap) | 1,843 | 11,690 |
| 5,000 gal (over cap) | 1,843 | 11,690 |
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