The Joint Travel Regulations (JTR), par. 020303 requires travelers (service members and civilians) on temporary duty at an ILP location to use adequate DoD lodging, Privatized lodging, or DoD Preferred Commercial lodging before other lodging options or reimbursement is limited to the government rate [authentication required, PDF, 33 pages].
When ILP lodging facilities are available at the traveler's destination and in DTS, the system automatically routes travelers to those facilities before displaying other lodging options.
If ILP facilities are available and a traveler chooses to stay in other commercial lodging, reimbursement is limited to the amount the Government would have paid if directed lodging were used.
If DoD Lodging is not available at the location, DTS automatically includes a certificate of non-availability number (CNA) in the authorization and displays either DoD Preferred Commercial lodging or FedRooms followed by other commercial lodging options.
When you use your Government Travel Charge Card (GTCC) for official travel, your hotel stay may be exempt from certain state and local sales tax. Some states require Government travelers to submit a form for this exemption. These forms are unique to each state (and in some cases, each city). Visit GSA's State Tax Map to find out if the state you're visiting offers tax exemptions and what specific requirements must be met to qualify. You can also watch a video on lodging and taxes [youtube.com] or look through common questions [gsa.gov].
DoD Preferred hotels are required to provide the required tax exempt forms in states where the Federal Government is tax exempt when using the GTCC.
Section 642 of the FY21 National Defense Authorization Act (NDAA) made permanent the pilot authority granted in section 914 of the FY15 NDAA, which authorized the Secretary of Defense to institute a government lodging program. That authority allows the Secretary of Defense to require both DoD civilian employees and service members to stay in DoD, Privatized, or DoD Preferred commercial lodging while on official travel.