Rainwater Harvesting in Utah
Utah (UT) receives an average of 12.2 inches of rainfall per year, placing it in the very low-rainfall category among US states. The wettest month is typically Mar, and the driest is Jul. Rainwater harvesting is restricted in Utah. A standard 1,500-square-foot asphalt shingle roof can collect approximately 9,421 gal per year, saving an estimated $37.68 annually at the state's average municipal water rate of 0.4 cents per gallon.
Monthly Rainfall in Utah
Understanding Utah's monthly rainfall distribution is essential for sizing your storage tank correctly. The table below shows average monthly rainfall and the resulting harvest from a 1,500-square-foot roof. Utah's 12.2 inches of annual rainfall is relatively low, making every drop valuable. Even in arid climates, a properly designed harvesting system provides meaningful water for drought-tolerant landscaping, container gardens, and supplemental outdoor use.
| Month | Rainfall (in) | Harvest (1,500 sq ft) |
|---|---|---|
| Jan | 1.2" | 897 gal |
| Feb | 1.1" | 822 gal |
| Mar | 1.4" | 1,047 gal |
| Apr | 1.4" | 1,047 gal |
| May | 1.4" | 1,047 gal |
| Jun | 0.7" | 523 gal |
| Jul | 0.6" | 449 gal |
| Aug | 0.7" | 523 gal |
| Sep | 0.9" | 673 gal |
| Oct | 1.2" | 897 gal |
| Nov | 1.0" | 748 gal |
| Dec | 1.0" | 748 gal |
| Total | 12.2" | 9,421 gal |
Harvest by Roof Size in Utah
Your actual harvest depends on how much roof area you connect to your collection system. Not every square foot of your roof needs to drain into your tank — many homeowners start by connecting just one or two downspouts covering a portion of their roof. The table below shows what different collection areas yield annually in Utah using an asphalt shingle roof at 80% efficiency.
| Roof Area | Annual Harvest | Rec. Tank Size | Annual Savings |
|---|---|---|---|
| 1,000 sq ft | 6,280 gal | 1,000 gal | $25.12 |
| 1,500 sq ft | 9,421 gal | 1,500 gal | $37.68 |
| 2,000 sq ft | 12,561 gal | 1,500 gal | $42.80 |
| 2,500 sq ft | 15,698 gal | 2,500 gal | $42.80 |
Upgrading to a metal roof (95% efficiency) boosts collection by about 19% compared to asphalt shingle. For example, a 1,500-square-foot metal roof in Utah captures approximately 11,186 gal per year when used for garden irrigation and toilet flushing for a household of two.
Rainwater Harvesting Laws in Utah
Utah restricts rainwater collection. As of 2010, residents may collect up to 2,500 gallons in covered storage containers, or use two containers with a combined capacity of no more than 100 gallons without registration. Larger systems require registration with the Division of Water Rights.
Regulation Summary for Utah
- Legal Status: Restricted — volume limits apply
- Max Collection: 2,500 gallons
- Permit Required: No — for standard residential systems
- Municipal Water Rate: 0.4 cents per gallon (state average)
Popular Uses for Harvested Rainwater in Utah
Utah homeowners use harvested rainwater for a variety of purposes. The most common applications are garden irrigation, lawn watering, and toilet flushing. Each use has different water requirements and may require different levels of filtration. Explore detailed guides for the most popular uses in Utah:
How Utah Compares to Similar States
The table below compares Utah with five states that have similar annual rainfall patterns. All calculations use a standard 1,500-square-foot asphalt shingle roof collecting water for garden irrigation.
| State | Annual Rainfall | Legal Status | Annual Harvest | Water Cost | Annual Savings |
|---|---|---|---|---|---|
| Utah | 12.2" | restricted | 9,421 gal | 0.4 c/gal | $37.68 |
| Wyoming | 12.9" | Legal | 8,748 gal | 0.5 c/gal | $43.74 |
| Arizona | 13.6" | Legal | 8,373 gal | 0.6 c/gal | $50.24 |
| New Mexico | 14.6" | Legal | 9,047 gal | 0.7 c/gal | $63.33 |
| Nevada | 9.5" | Legal | 5,683 gal | 0.7 c/gal | $39.78 |
| Montana | 15.3" | Legal | 10,692 gal | 0.5 c/gal | $53.46 |
Tips for Rainwater Harvesting in Utah
In a low-rainfall state like Utah (12.2 inches per year), every gallon of harvested rainwater is especially valuable. Focus on drought-tolerant landscaping (xeriscaping) that requires minimal supplemental watering, and use harvested rainwater to support container gardens, potted plants, and select high-value plantings. A metal roof is strongly recommended to maximize collection from each rain event. Size your tank generously relative to your roof area — in Utah, rain events are often separated by weeks of dry weather, so you need enough storage to capture and hold the occasional heavy rain. Even modest systems provide meaningful water savings in Utah due to the higher-than-average water costs that accompany dry climates.
Calculate Your Specific Harvest in Utah
The estimates above use standardized assumptions. Use our Rainwater Harvesting Calculator to enter your exact roof area, material, household size, and intended uses for a customized analysis tailored to your property in Utah. You can also browse all states to compare potential across the country, or explore tank sizes and water uses for detailed information on system components and water budgeting.