U.S. military bases are home to over a million real property assets—buildings, piers, pipelines, and other structures. That infrastructure supports military forces by providing facilities for training, storing equipment, housing troops, and other activities, but it must compete with other high-priority purposes for funds, such as buying equipment, paying salaries, and carrying out military missions. When maintenance has not been funded at the levels the Department of Defense (DoD) views as necessary, a backlog of deferred maintenance has accrued.

In this report, the Congressional Budget Office focuses on a subset of those assets: more than 100,000 buildings maintained by the active components of the military services in the United States and its territories. CBO analyzed data on the buildings’ age, condition, and capacity to support their users’ missions. The agency then estimated how much completing their deferred maintenance would cost.

Deferred maintenance is maintenance that DoD’s real property managers want to undertake but that has not been carried out. It includes regular preventive maintenance and repairs to improve a property’s condition to meet the department’s standards. Failing to perform such maintenance could accelerate the natural degradation of property and increase the costs of renovation in the future.

In two previous reports on the state of the Army’s and the Navy’s buildings, CBO also analyzed the costs of renovation and modernization. A comparative analysis of renovation and modernization across the four services was not possible because the Air Force and the Marine Corps did not provide the necessary data.

The analytical approach CBO used for deferred maintenance in this report is the same as that for the two earlier reports.

Deferred Maintenance of the Military Services’ Buildings

The services report a facility condition index (FCI) for each building, a score reflecting how the estimated cost of a building’s deferred maintenance compares with that building’s replacement value. FCI scores range from 0 to 100: The higher the score, the lower the deferred maintenance cost. For example, a score of 95 indicates that the cost of completing deferred maintenance would equal 5 percent of a building’s replacement value.

Accumulated deferred maintenance is derived from the FCI score:

where dm is accumulated deferred maintenance, FCI is the index value, and V is the building’s replacement value. The sum of dm for all of the buildings examined provides an estimate of the backlog of deferred maintenance.

In total, the four services’ backlog of building maintenance was about $50 billion for the roughly 101,500 buildings analyzed, as of September 2020. The Army and Navy had the largest shares of that total, accounting for a combined 70 percent of total deferred maintenance costs and 68 percent of the buildings. Overall, the backlog for all four services represented about five years of typical budget amounts for property maintenance, but the ratio was higher for the Army and Navy because of their larger backlogs.

Real Property Assets Considered in CBO’s Analysis

In its analysis, CBO included buildings from the inventories of the Air Force, Army, Marine Corps, and Navy that met the following criteria:

• The active component of the service was responsible for maintaining them. (CBO excluded buildings maintained by reserves and buildings maintained by other entities, such as the Defense Logistics Agency and private organizations.)
• They were in active use by the service.
• They were buildings—not structures such as piers and pipelines.
• They were located on bases inside the United States and its territories.

  Buildings Considered in CBO’s Analysis, as a Subset of Real Property Assets

  

  Of the roughly 1 million real property assets on military bases in 2020, CBO focused on about 101,500, or 10 percent. Those buildings were in the United States or its territories, actively used, and maintained by the service itself.

The Ages of the Military Services’ Buildings

On average, as of 2020, the Army’s and Navy’s buildings were the oldest, with an average age of 47 years. More than 40 percent of the Air Force’s and Army’s buildings had exceeded their expected lifespan.

• The book value of a building is calculated by deducting accumulated depreciation from the original cost. Book value does not reflect capital improvements that extend a building’s useful life.
• The replacement value is the cost to replace a building with one of similar type and quality.
• A building’s intended useful life is the period during which its book value is positive, that is, until depreciation has reduced the building’s book value to zero.

  Characteristics Determining Buildings’ Lifespans

  

  The Marine Corps had the youngest buildings, on average.

  The Marine Corps and Navy had proportionally fewer buildings beyond their expected lifespans.

The Facility Condition Index Scores of the Military Services’ Buildings

As of 2020, although the Marine Corps had the newest buildings, FCI scores of that service’s buildings were most negatively affected by age: For every 10 years older a building was, the average FCI score was 2.5 points lower. The Air Force had the lowest rates of age-based decline: Each additional decade of age correlated with an average drop in FCI score of 0.8, whereas the Army and Navy had drops of 1.4 and 1.6 points, respectively.

The Facility Condition Index Scores Weighted by Building Replacement Value

In addition to calculating average FCI scores by building for each service, CBO calculated a weighted average, weighting each building’s score by its replacement value. The weighted average FCI score can be expressed as

where V is the value of each building. Having a higher weighted average score suggests that a service’s buildings with the highest replacement value are in better-than-average condition.

Deferred Building Maintenance Costs by Base

Of the 20 bases with the highest deferred maintenance costs in 2020, the Army accounted for 8; the Navy, 7; the Marine Corps, 3; and the Air Force, 2. That snapshot corresponds with the fact that, on average, among all of the services’ buildings, the Air Force’s were in the best condition, as that service had 25 percent of the total number of bases, but only 2 were in the top 20.

The rankings of individual bases could be different from what is presented here if the services or base managers varied in applying criteria in their evaluations of building conditions. FCI scores are self-reported, which could lead to some inconsistency among the reports.

About This Document

This report was prepared at the request of the Chairman and Ranking Member of the Subcommittee on Readiness of the House Armed Services Committee. In keeping with the Congressional Budget Office’s mandate to provide objective, impartial analysis, the report makes no recommendations.

Nikhil Bhandarkar, Edward G. Keating, and Adebayo Adedeji (formerly of CBO) prepared this report with guidance from David Mosher. David Newman and Joyce Shin provided comments, and Adam Talaber fact-checked the report.

Ellen Pint of RAND Corporation and Andrew Tilghman of the Congressional Research Service provided expert insights. The assistance of external reviewers implies no responsibility for the final product; that responsibility rests solely with CBO.

Jeffrey Kling and Robert Sunshine reviewed the report. John Skeen edited it, and Casey Labrack created the graphics and prepared the text for publication. The report is available at www.cbo.gov/publication/60192.

CBO seeks feedback to make its work as useful as possible. Please send comments to communications@cbo.gov.

Phillip L. Swagel

Director

August 2024