Are all the Prescott Wells going dry? NO with the FACTS

Overview

The memorandum is a meta-analysis of groundwater conditions in the Little Chino Basin within the Prescott Active Management Area (AMA). It reviews scientific literature, hydrologic data, and well records to evaluate recharge rates, groundwater level trends, aquifer storage, and claims of wells going dry. The analysis was prepared for Prescott Truth in March 2026.

Recharge in the Little Chino Basin

Recharge estimates vary widely across studies, but most converge around 1–3.8% of annual precipitation, with an average of ~2.2%.

Key findings

• Annual precipitation across the basin ranges from 198,000 to 317,000 acre-feet depending on elevation and data source.

• Using the average recharge rate (2.2%), estimated natural recharge is:

  • 4,358 AFY (low precipitation scenario)

  • 5,693 AFY (moderate)

  • 6,980 AFY (high)

• Artificial recharge adds ~7,500 AFY on top of natural recharge.

• Isotope studies show winter precipitation and mountain-block runoff dominate recharge.

• The document notes: “Identifiable summer recharge is very weak to absent; and runoff from mountain blocks is the most likely main source of recharge.”

Outlier

ADWR’s 2024 Supply & Demand report estimates 6.3–10.1% recharge, far higher than all other scientific studies.

Groundwater Level Trends

Groundwater levels have been declining for decades, consistent with long-term pumping exceeding recharge.

Key findings

• Across 32 wells, the average decline is –1.63 ft/year.

• Little Chino subbasin wells decline more slowly (–1.16 ft/year) than Agua Fria wells (–1.77 ft/year).

• Some localized areas show rising water tables due to artificial recharge or over-irrigation.

• The report states: “Groundwater declines of between 1–2 ft per year in the Little Chino Valley basin are cited by multiple sources going back to 1967.”

Aquifer Storage and Future Supply

The aquifer system includes a thick upper alluvial unit and a lower volcanic unit, together providing substantial storage.

Key findings

• Upper alluvial aquifer thickness: up to ~1,200 ft.

• Lower volcanic aquifer thickness: ~200 ft.

• Specific yield in the upper aquifer: 0.08–0.12, meaning 96–144 ft of drainable water in the thickest areas.

• Prescott’s Assured Water Supply designation includes:

  • 9,466 AFY local groundwater rights

  • 7,041 AFY surface water (Watson & Willow Lakes)

  • ~3,650 AFY treated effluent for recharge

  • 8,067 AFY Big Chino Water Ranch groundwater (infrastructure not yet built)

The report emphasizes that the current ~14-inch annual water table decline is small relative to total aquifer thickness.

Rumors of Wells Going Dry

The memo investigates claims that “wells are going dry all over the place” and finds no evidence supporting widespread failures.

Key findings

• CWAG’s analysis used aerial imagery to identify properties with water tanks and assumed tanks = failed wells.

• The memo notes: “It seems highly unlikely that most of these water storage tanks signify wells that went dry.”

• Water haulers report no surge in customers due to dry wells.

• Some isolated well failures occur near mountain fronts, where aquifers are thin and drought-sensitive.

Conclusions

The memo’s final conclusions include:

• Recharge: Average annual recharge is 4,300–7,000 AFY, plus ~7,500 AFY artificial recharge.

• Groundwater levels: Declining at ~1.6 ft/year overall, consistent with long-term trends.

• Aquifer storage: The basin contains substantial stored groundwater, and current declines are small relative to aquifer thickness.

• Wells going dry: No evidence of widespread failures; isolated issues likely tied to drought and shallow fringe areas.