How far will Lake Mead fall after all of its “banked” water has been withdrawn?

A skeleton wearing a straw hat and sunglasses relaxes in a beach chair in a desert landscape, next to a cooler labeled 'IGLOO ICY BEERS'. A bottle is in its hand and a towel is laid on the ground.
Image created by Google Gemini, May 6th, 2026, from the prompt: “generate a funny picture of a skeleton wearing a beach hat in the desert”.

by Robert Marcos, photojournalist

Water that’s banked in Lake Mead is officially called “Intentionally Created Surplus“, or ICS. The ICS allows major water users to store conserved or unused Colorado River water in the reservoir for their future use. It’s probably obvious to most of you but since Lake Mead serves as a reservoir for the lower basin, the ICS is primarily a program that serves water agencies in the lower basin.1

As of April 12, 2026, Lake Mead’s water volume was 8.41 million acre-feet, or roughly 32% of its total capacity. But while writing this article we were made aware that we should subtract Lake Mead’s deadpool – which is estimated at 2.5 million acre feet of water that cannot be utilized because Hoover Dam’s water intake towers and turbines are physically positioned too high to draw that water.2 Therefore the approximately 2.67 to 3.47 million acre feet of that water that’s currently banked represents somewhere between 44% and 58% of the 6 million acre feet of water that’s available in Lake Mead.

Here’s a list of the water agencies and the estimated amount of water that each of them have currently banked in Lake Mead –

Arizona: currently holds approximately 500,000 to 600,000 acre-feet in its dedicated ICS accounts.

California: As of May 2026, California has roughly 1.2 to 1.4 million acre-feet of water banked in Lake Mead through the ICS and other conservation programs. Major participants include the Metropolitan Water District of Southern California, the Imperial Irrigation District, and the Palo Verde Irrigation District.4

Nevada: As of May 2026, Nevada has approximately 954,000 acre-feet of water banked in Lake Mead through the ICS program. This total represents a major portion of Nevada’s overall “water savings account,” which includes several different banking locations and programs.5

Gila River Indian Community: As of May 2026, the Gila River Indian Community has banked approximately 320,000 acre-feet in Lake Mead through the ICS program. The Community also contributed larger amounts of water to the reservoir through multiple conservation programs. Since 2019, the Community has contributed roughly 850,000 acre-feet to Lake Mead. This includes ICS, mandatory cuts, and “system conservation” water that remains in the lake permanently to boost elevation rather than being banked for future withdrawal. The Community committed to leaving 125,000 acre-feet per year in the reservoir for 2023, 2024, and 2025. These efforts, funded by the Inflation Reduction Act, have collectively added about two feet to Lake Mead’s elevation. New agreements signed in late 2024 and 2025 involve infrastructure projects like lining irrigation canals that can save an additional 73,000 to 78,000 acre-feet over the next decade.6

Mexico: As of May 2026, Mexico has approximately 200,000 acre feet of water banked in Lake Mead through the ICS program and related binational agreements. Mexico was granted the right to store water in Lake Mead following a 2010 earthquake that damaged its irrigation infrastructure. By 2026, these stored volumes have stabilized at around 200,000 acre-feet as Mexico uses the lake as a buffer against shortages.7

3 thoughts on “How far will Lake Mead fall after all of its “banked” water has been withdrawn?”

  1. I love this article and this is a question I’ve been interested in, but the math in this article is weird. It says together it all adds up to 2.67 million af, but when I add up the numbers listed in the paragraphs, I get 3.47 million. Thanks

    Reply

  2. Thanks gentlemen. Peter, as a water engineer I’d value greatly value your input. Here’s what my second “data run” came up with, compliments of the MWD:

    “Approximately 1.3 million acre-feet of Lake Mead’s current water supply is attributable to the ICS program, based on the Metropolitan Water District’s 2025 analysis showing that 1.3 MAF of EC ICS currently resides in Lake Mead. That figure is the best direct estimate of the amount of Lake Mead storage contributed by ICS, though the paper notes that total EC ICS remaining in the system is about 2.8 MAF and that some additional water has become system water through assessments and losses.”

    “EC ICS” means Extraordinary Conservation Intentionally Created Surplus in Colorado River water management. It refers to water savings created through approved conservation actions, such as fallowing land or using another water source instead of Colorado River water, so the saved water can be stored in Lake Mead”.

    I hope there’s someone who understands this!

    Robert Marcos

    Reply

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