	Introduction

Each of the four major federal land management agencies has maintenance responsibility for tens of thousands of diverse assets in dispersed locations. These agencies are the Bureau of Land Management (BLM), Fish and Wildlife Service (FWS), and National Park Service (NPS), all within the Department of the Interior (DOI), and the Forest Service (FS) within the Department of Agriculture. Deferred maintenance and repairs often are called the maintenance backlog . Debate has focused on varied issues, including the level of funds needed to reduce deferred maintenance, whether agencies are using existing funding efficiently, the priority of deferred maintenance relative to regular maintenance, and whether additional sources of funds should be directed to maintenance. Other issues include how to balance the maintenance of existing infrastructure with the acquisition of new assets, whether disposal of assets is desirable given limited funding, and how much to prioritize maintaining infrastructure relative to other government functions. This report focuses on these issues. It first provides agency deferred maintenance estimates for FY2018, the most recent fiscal year for which this information is available. FY2018

The four agencies had combined FY2018 deferred maintenance estimated at $19.38 billion. The FS share was 27% of the total, with an estimated deferred maintenance of $5.20 billion. The FWS portion was 7%, reflecting the agency's deferred maintenance of $1.30 billion. It ended the decade relatively flat, with an increase of $0.36 billion overall, from $19.02 billion to $19.38 billion, or 2%. Both the BLM and NPS estimates increased, by $0.42 billion (80%) and $1.75 billion (17%), respectively. Figure 1 depicts the annual changes in current dollars for each agency and for the four agencies combined. By contrast, as shown in Table 2 and Figure 2 , in constant dollars, the total deferred maintenance estimate for the four agencies decreased over the course of the ten-year period by $3.61 billion, from $22.99 billion to $19.38 billion, or 16%. In both current and constant dollars, in each fiscal year NPS had the largest portion of total deferred maintenance and considerably more than any other agency. FS consistently had the second-largest share, followed by FWS and then BLM. The asset class or category that included roads typically comprised the largest portion of each agency's deferred maintenance. Issues in Analyzing Deferred Maintenance

Fluctuations in deferred maintenance estimates are likely the result of many factors, among them estimation methods, levels of funding, and asset portfolios, as discussed below. The extent to which these and other factors affected year-to-year changes in any one agency's maintenance backlog is unclear, in part because comprehensive information is not readily available in all cases or has not been examined. With regard to facility assessment, agencies have enhanced efforts to define and quantify the maintenance needs of their assets. The FWS change in the method of estimating deferred maintenance for roads, bridges, and trails appears to be a primary reason for the decreased estimate for this category and total FWS deferred maintenance over the 10-year period. Assets

The asset portfolios of the four agencies vary considerably in terms of number, type, size, age, and location of agency assets.
Each of the four major federal land management agencies maintains tens of thousands of diverse assets, including roads, bridges, buildings, and water management structures. These agencies are the Bureau of Land Management (BLM), Fish and Wildlife Service (FWS), National Park Service (NPS), and Forest Service (FS). Congress and the Administration continue to focus on the agencies' deferred maintenance and repair of these assets—in essence, the cost of any maintenance or repair that was not done when it should have been or was scheduled to be done. Deferred maintenance and repair is often called the maintenance backlog.
In FY2018, the most recent year for which these estimates are available, the four agencies had combined deferred maintenance estimated at $19.38 billion. This figure includes $11.92 billion (62%) in deferred maintenance for NPS, $5.20 billion (27%) for FS, $1.30 billion (7%) for FWS, and $0.96 billion (5%) for BLM. The estimates reflect project costs.
Over the past decade (FY2009-FY2018), the total deferred maintenance for the four agencies fluctuated, peaking in FY2012 and ending the decade relatively flat in current dollars. It increased overall by $0.36 billion, from $19.02 billion to $19.38 billion, or 2%. Both the BLM and NPS estimates increased, whereas the FWS and FS estimates decreased. By contrast, in constant dollars, the total deferred maintenance estimate for the four agencies decreased from FY2009 to FY2018 by $3.61 billion, from $22.99 billion to $19.38 billion, or 16%. The BLM estimate increased, whereas estimates for the other three agencies decreased.
In each fiscal year, NPS had the largest portion of the total deferred maintenance, considerably more than any of the other three agencies. FS consistently had the second-largest share, followed by FWS and then BLM. Throughout the past decade, the asset class that included roads comprised the largest portion of the four-agency combined deferred maintenance.
Congressional debate has focused on varied issues, including the level and sources of funds needed to reduce deferred maintenance, whether agencies are using existing funding efficiently, how to balance the maintenance of existing infrastructure with the acquisition of new assets, whether disposal of assets is desirable given limited funding, and the priority of maintaining infrastructure relative to other government functions.
Some question why deferred maintenance estimates have fluctuated over time. These fluctuations are likely the result of many factors, among them the following:
Agencies have refined methods of defining and quantifying the maintenance needs of their assets. Levels of funding for maintenance, including funding to address the maintenance backlog, vary from year to year. Economic conditions, including costs of services and products, also fluctuate. The asset portfolios of the agencies change, with acquisitions and disposals affecting the number, type, size, age, and location of agency assets.
The extent to which these and other factors affected changes in each agency's maintenance backlog over the past decade is not entirely clear. In some cases, comprehensive information is not readily available or has not been examined.