Herriman, UT rainwater: 25,760 gallons off a roof
Herriman, UT: gallons off the roof each year
25,760gallons a year
That is a 1,500 sq ft asphalt roof under Herriman, UT's normal 32.4 inches of rain, about 795 gallons for every inch that falls.
In Herriman, UT 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 Dry Fork station (9.5 mi away). Herriman, UT ranks 3rd wettest of the 67 cities covered in Utah.
Month by month in Herriman
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.20 | 2,543 | |
| Feb | 3.14 | 2,496 | |
| Mar | 3.98 | 3,163 | |
| Apr | 4.33 | 3,442 | 2 |
| May | 3.09 | 2,456 | 157 |
| Jun | 1.55 | 1,232 | 349 |
| Jul | 1.26 | 1,001 | 385 |
| Aug | 1.18 | 938 | 395 |
| Sep | 1.76 | 1,399 | 323 |
| Oct | 2.54 | 2,019 | 226 |
| Nov | 3.07 | 2,440 | |
| Dec | 3.31 | 2,631 |
Apr is the wettest month (4.33 in, 3,442 gal off the roof); Aug the driest (1.18 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 Herriman
Best fit: 2 linked 55-gallon barrels, which delivers about 1,513 gallons to the garden in a normal year (82.3% 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 Herriman's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 1,272 | 22,927 |
| 110 gal | 1,513 | 22,686 |
| 165 gal | 1,513 | 22,686 |
| 275 gal | 1,513 | 22,686 |
| 550 gal | 1,513 | 22,686 |
| 1,000 gal | 1,513 | 22,686 |
| 1,500 gal | 1,513 | 22,686 |
| 2,500 gal | 1,513 | 22,686 |
| 5,000 gal (over cap) | 1,513 | 22,686 |
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 Utah?
Up to 2 covered containers of max 100 gal each with no registration; with free registration at the Utah Division of Water Rights, total storage up to 2,500 gal. Use limited to the same parcel where captured.
Checked against the current source on 2026-11-06. Source