Lakewood, CO rainwater: 14,108 gallons off a roof
Lakewood, CO: gallons off the roof each year
14,108gallons a year
That is a 1,500 sq ft asphalt roof under Lakewood, CO's normal 17.8 inches of rain, about 795 gallons for every inch that falls.
In Lakewood, 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 Denver 6.1 Wsw station (1.0 mi away). Lakewood, CO ranks 19th wettest of the 53 cities covered in Colorado.
Month by month in Lakewood
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.66 | 525 | |
| Feb | 0.86 | 684 | |
| Mar | 1.49 | 1,184 | |
| Apr | 2.48 | 1,971 | 233 |
| May | 2.89 | 2,297 | 182 |
| Jun | 1.67 | 1,327 | 334 |
| Jul | 2.08 | 1,653 | 283 |
| Aug | 1.71 | 1,359 | 329 |
| Sep | 1.25 | 994 | 386 |
| Oct | 1.16 | 922 | 398 |
| Nov | 0.84 | 668 | |
| Dec | 0.66 | 525 |
May is the wettest month (2.89 in, 2,297 gal off the roof); Jan 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.
What size rain barrel for Lakewood
Best fit: 2 linked 55-gallon barrels, which delivers about 1,842 gallons to the garden in a normal year (85.8% 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 Lakewood's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 1,364 | 12,128 |
| 110 gal | 1,842 | 11,650 |
| 165 gal (over cap) | 1,871 | 11,622 |
| 275 gal (over cap) | 1,871 | 11,622 |
| 550 gal (over cap) | 1,871 | 11,622 |
| 1,000 gal (over cap) | 1,871 | 11,622 |
| 1,500 gal (over cap) | 1,871 | 11,622 |
| 2,500 gal (over cap) | 1,871 | 11,622 |
| 5,000 gal (over cap) | 1,871 | 11,622 |
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