Highlands Ranch official warns Douglas County groundwater is finite, urges surface-water focus

Rick McLeod, water resources manager at Highlands Ranch Water and Sanitation District, told the Douglas County Water Commission on July 28 that Highlands Ranch has pursued a mix of surface and groundwater, along with storage and reuse projects, to reduce long-term reliance on Denver Basin groundwater and to avoid what he described as an eventual ‘‘crisis in groundwater.’’

McLeod spoke during the commission’s regular meeting in Castle Rock and summarized 44 years of the district’s development of surface-water contracts, storage and aquifer storage and recovery (ASR). He said Highlands Ranch now serves roughly 110,000 people and is about 95–98% built out. He told commissioners the district’s long-term goal is ‘‘100% surface water in average hydrologic years.’’

Why it matters: McLeod said Denver Basin groundwater is a finite resource and that some Highlands Ranch wells have already lost economic viability. The district’s experience, he said, shows the limits of relying solely on groundwater and underscores the cost, complexity and political difficulty of acquiring surface water and storage.

Key claims and supporting details

- Sources and contracts: McLeod said Highlands Ranch secured long-term contracts and storage access that let the district move from early groundwater dependence toward surface water. He cited long-term contracts with the city of Englewood (including storage and diversion access to McClellan Reservoir and Chatfield Reservoir), agreements acquired through purchase or lease and participation in regional projects such as the WISE program. He said two long-term contracts with Inglewood provide roughly 6,000 acre-feet per year and access to facilities that were critical early in buildout.

- Storage and conveyance: Highlands Ranch built South Platte Reservoir (a lined former gravel pit) and leased space in McClellan Reservoir; the district also obtained a portion of storage in Chatfield Reservoir after a multi‑decade effort. McLeod described use of legacy agricultural ditches (City Ditch, Last Chance Ditch and Nevada Ditch) and an alluvial well field near Littleton as important conveyance and capture features that support reuse and ASR.

- Conservation and budgeting: McLeod credited a household water‑budget rate structure, adopted after a severe drought around 2002, with flattening per‑capita demand. He said the district’s demand estimate for buildout is roughly 0.4 acre-feet per year per connection and an overall demand near 20,000 acre-feet per year. He estimated recently that converting existing nonfunctional turf could save about 800 acre-feet annually—small relative to overall demand but still meaningful.

- Groundwater limits and ASR: McLeod said Highlands Ranch holds decreed rights totaling roughly 18,000 acre-feet but that legal decrees do not equal physical pumping rates. He said the system today can pump roughly half the rate that wells produced when first installed, and that 16 of 52 drilled wells are currently not usable because water levels have fallen enough to make them uneconomic. He described the Arapahoe aquifer levels in the district as ‘‘about halfway down’’ and urged other Douglas County utilities to treat Denver Basin groundwater as a time‑limited resource. McLeod also described years of testing and deployment of aquifer storage and recovery (ASR) across aquifers, but noted that ASR requires wet years and filled reservoirs before injection can proceed at scale.

Selected quotes

- McLeod, quoting a 1985 statement by then-Department of Natural Resources executive director David Goetches: "Senate Bill 213 is effectively a legislative announcement that nontributary groundwater is available for total depletion...We are moving inexorably toward a crisis in groundwater. It comes quietly and it comes slowly." He said the district has used that warning as a guiding principle.

- "Our goal is a 100% surface water in average hydrologic years," McLeod said, describing the district—s planning target while acknowledging groundwater use will still be required in dry years and for operational flexibility.

Questions and follow-ups

Commissioners asked about the sources Englewood uses to supply Highlands Ranch; McLeod said the city—s water rights and diversions are tied to Chatfield and McClellan reservoirs and other West‑slope and South Platte sources. Commissioners also asked about the household budget approach (McLeod said budgets are set using historical use, lot size and household factors, with waivers available in special cases) and about reuse/purple‑pipe distribution (McLeod said the district reuses effluent for golf courses and other nonpotable irrigation near treatment plants).

Context and takeaways

McLeod framed Highlands Ranch as having benefited from a combination of fortuitous early contracts, nearby river infrastructure and deliberate investments in storage, conveyance and conservation. He cautioned that acquiring additional surface water and storage is costly, politically difficult and likely to be the central challenge for Douglas County utilities seeking to replace Denver Basin groundwater over the long term.

Next steps

After McLeod—s presentation, county staff and consultants reported a schedule change for the county—s water master plan: staff said they are working to complete a draft technical analysis by the end of 2025 and begin public workshops in early 2026.

Ending

McLeod closed by urging commissioners to treat groundwater as finite and to prioritize surface water, storage and regional cooperation in the county master plan.