by Robert Marcos, photojournalist
We’ve heard thousands of times (without sources being provided) that 40 million people are dependent upon Colorado River water. But which cities in the American Southwest are 100% dependent and would vanish without it?
YUMA ARIZONA
Yuma, Arizona, relies on the Colorado River for all of its municipal drinking water and is heavily tied to the river for its massive agricultural economy. Yuma has a population of 103,500 permanent residents which share a Colorado River water entitlement of 980,000 acre feet: 97% of which is used for agriculture and the remaining 3% is allocated for domestic, commercial, and military operations – such as those at the U.S. Army Yuma Proving Ground. Yuma conserves its water through high-tech agricultural irrigation, extensive canal automation, municipal restrictions, and wastewater recycling. Despite being a major agricultural hub, local farmers have reduced water usage by nearly 20% while doubling food production over the last three decades.
Agriculture & Irrigation
With agriculture accounting for the vast majority of water use, Yuma’s agricultural sector employs cutting-edge conservation techniques: 1
Automated & Advanced Irrigation: Farmers utilize furrow, sprinkler, and drip systems optimized for specific crops. Irrigation districts are rolling out autonomous systems with remote-controlled canal gates to deliver water in real-time and eliminate excess diversion.
Precision Technology: Fields are leveled using GPS and laser technology, which minimizes runoff and waste.
Concrete-Lined Canals: Over 99% of farmer-owned ditches and irrigation networks are lined with concrete or buried as underground pipelines to eliminate seepage.
Municipal & City Efforts
The City of Yuma actively manages its municipal supply through strict conservation and drought response plans.2
Landscape Restrictions: The city encourages residents to adopt desert landscaping and transition away from water-heavy turf. Residents are advised to water only between 7 p.m. and 7 a.m. to prevent evaporation.
City Facilities: During declared water shortages, the city limits operations of water features, reduces winter grass overseeding, and limits facility water use.
Wastewater Recycling: The city recycles about 40% of its treated municipal water, which is safely discharged back into the environment to recharge the local aquifer and supply the Colorado River.
GREEN RIVER, WYOMING
As of 2026, the city of Green River, Wyoming had an estimated population of 11,307 people. The city itself does not hold an independent interstate water right; instead, its water use is governed by Wyoming’s state allocation within the broader “Law of the River” framework. Under the Upper Colorado River Basin Compact of 1948, the State of Wyoming is entitled to 14.00% of the total Upper Basin water allocation. This translates to a maximum full-supply entitlement of 1,043,000 acre-feet of water per year, the vast majority of which is sourced from the Green River basin.3
The city of Green River, Wyoming manages water conservation through modernized infrastructure, rigorous system auditing, and targeted wastewater recycling, operating in tandem with broader basin-wide conservation blueprints. Because Wyoming faces growing pressure to safeguard its Upper Colorado River Basin share, local municipal initiatives focus heavily on eliminating system losses and maximizing structural efficiency.4
Advanced Infrastructure and Metering
Universal Municipal Metering: The City of Green River Water Distribution department actively maintains over 4,200 water meters across commercial and residential lines. Universal metering prevents unmonitored usage and allows for exact data tracking to optimize conservation modeling.
Pressure Management: The distribution team actively manages 25 Pressure Reducing Valves (PRVs). Maintaining controlled water pressure minimizes stress on pipes, directly preventing underground ruptures and chronic structural leaks.
System Leaks and Audits: The city continuously updates its sanitary, stormwater, and water line mapping to execute aggressive leak detection and repair protocols.5
LAKE HAVASU, ARIZONA
Lake Havasu, Arizona, has a permanent population of 59,871 and is entitled to 28,582 acre feet of Colorado River water, annually. The city employs a multi-faceted approach to water management:6
Advanced Wastewater Recycling: The city operates three wastewater treatment plants that produce A+ quality reclaimed water. This recycled water is used to irrigate local golf courses and parks instead of draining fresh drinking water supplies, and the surplus is safely returned to the Colorado River for downstream use.
Advanced Metering Infrastructure (AMI): Lake Havasu is replacing approximately 32,000 residential water meters with smart technology. This system provides near real-time usage data and leak detection alerts via the EyeOnWater Platform, allowing residents to quickly spot and fix running toilets or plumbing leaks.
Mandatory and Voluntary Measures: The city’s conservation plan includes guidelines that limit non-essential uses like irrigation and prevent water waste. Residents are encouraged to water early in the morning to reduce evaporation and use mulch to lock in soil moisture.
BULLHEAD CITY, ARIZONA
Bullhead City Arizona has a permanent population of 43,200 and an annual entitlement to 15,210 acre feet of Colorado River water. Bullhead City, Arizona, actively combats Colorado River water shortages through phased municipal codes. Key actions include:7
Phased Restrictions: The city’s code outlines voluntary rules for Tier 1 shortages (fixing leaks, taking shorter showers), which escalate to mandatory bans on misting systems, decorative fountains, and driveway washing during Tier 2 shortages.
Turf Reduction Programs: Bullhead City offers rebates for replacing high-water-use grass with desert landscaping. The city also partners with local HOAs, using state grants to fund large-scale grass removal and park revitalization projects.
Device Rebates: The city provides direct financial incentives for residents and businesses to install smart irrigation controllers, high-efficiency toilets, washing machines, and hot water recirculation systems.
Aquifer Injection: The city recovers effluent (reclaimed water) at the Section 10 Wastewater Treatment Plant, injecting it into the Colorado River aquifer to ensure it is returned to the Colorado River system as return flow.8