Oro Valley’s water supply was not built through a single project or decision. It is the result of decades of planning, investment and cooperation by Town leaders, utility professionals, regional partners and residents—an effort we examine in this two series. Today we discuss life before CAP and what led up to its introduction in the Oro Valley Water System.
Our recent article explained why Lake Powell’s decline matters to Oro Valley. That connection did not exist when the Town created its Water Utility 30 years ago. At the time, Oro Valley relied entirely on groundwater. Every gallon delivered to a home or business came from a well. There was no CAP water in the system, no reclaimed-water network serving golf courses and no large reserve of stored water credits. That system supported the community for years. It was not sustainable indefinitely.
The Town inherited a groundwater-dependent system
Oro Valley created its Water Utility in May 1996 by purchasing the private Cañada Hills and Rancho Vistoso water companies. The new utility had approximately 9,800 connections serving about 26,000 residents. It also inherited separate water systems, different rate structures and wells of varying age and condition. Those systems had to be integrated while continuing to provide reliable water service.
Most importantly, they all depended on the same source: groundwater. That dependence became more concerning as Oro Valley grew. The Town’s population increased from approximately 6,670 in 1990 to nearly 30,000 by 2000. New homes, businesses, schools, parks and landscaped areas placed greater demands on the aquifer beneath the community.
By 1999 aquifer was showing the strain
Former Oro Valley Water Utility Director Alan Forrest later recalled that water levels in the Town’s wells were falling by an average of approximately six feet a year. A well failure during the summer of 1999 demonstrated how vulnerable the system could be. One of the two wells serving the Countryside area suffered a major failure during the hottest part of the year, when water demand was near its peak.
The Town arranged a temporary connection with Tucson Water to help maintain household service and the water needed for fire protection. The immediate crisis was resolved, but the larger problem remained.
Oro Valley needed to diversify its water supply.
Oro Valley had the legal right to pump groundwater. That did not mean the aquifer could sustain unlimited pumping. A 2007 groundwater study later estimated that the aquifer could sustainably provide approximately 6,360 acre-feet annually. Continued growth based almost entirely on wells would increase the risk of falling water levels, declining well production and higher pumping costs.
Reclaimed water came first
The first major step was to stop using drinking water for purposes that did not require it. Oro Valley negotiated with Tucson Water to obtain treated wastewater for irrigation. The Town then developed a two-phase reclaimed-water system costing approximately $21.8 million. Beginning in 2005, reclaimed water was delivered through a separate system of “purple pipes” to golf courses and other large turf areas. That change reduced pressure on the aquifer because water used on golf courses, parks and school grounds no longer had to come from the potable groundwater supply.
Tomorrow: Reclaimed water helped. But, it did not provide another source of drinking water. For that, Oro Valley needed access to Central Arizona Project water.
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