RoofRainYield

Orem, UT rainwater: 13,663 gallons off a roof

Rainwater from a roof in Orem, UT

13,663gallons a year

That is a 1,500 sq ft asphalt roof under Orem, UT's normal 17.2 inches of rain, about 795 gallons for every inch that falls.

Orem, UT has gaps between storms long enough to drain a single barrel. Around 275 gallons of storage catches most of what is worth catching.

Rainfall: NOAA 1991-2020 climate normals, the Provo Byu station (4.4 mi away). Orem, UT ranks 49th wettest of the 67 cities covered in Utah.

Month by month in Orem

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan1.951,550
Feb1.561,240
Mar1.551,232
Apr1.921,526303
May2.011,598292
Jun0.93739426
Jul0.51405479
Aug0.73580451
Sep1.24986388
Oct1.591,264344
Nov1.391,105
Dec1.811,439

May is the wettest month (2.01 in, 1,598 gal off the roof); Jul the driest (0.51 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 Orem?

Best fit: a 275-gallon tote or tank, which delivers about 2,404 gallons to the garden in a normal year (89.6% of its need).

If you set one up, link barrels with a short hose at the base so they fill and drain together, and check the overflow points away from the house.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal1,20711,721
110 gal1,80011,127
165 gal2,16110,767
275 gal2,40410,524
550 gal2,40410,524
1,000 gal2,40410,524
1,500 gal2,40410,524
2,500 gal2,40410,524
5,000 gal (over cap)2,40410,524

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