The Arsenal Workload Sustainment Act aims to boost the use of government-owned Army arsenals and manufacturing facilities by restricting how much defense work can be contracted out to private companies. Under the bill, no more than 50 percent of funds for certain Army workload activities can go to private contractors, while the remaining funds must be used for government employees or public-private partnerships that include Army arsenals. The Secretary of Defense can waive this requirement only for national security reasons, with a 30-day notification period to Congress. Additionally, the bill gives preference to contractors who partner with government arsenals by adding a 20 percent cost penalty to bids that do not include them. Starting immediately, the Secretary of Defense must submit annual reports to Congress detailing the workload at each Army arsenal, prior-year achievements, and capital investment needs to maintain operational capacity.