Preserving Data in Government Act of 2017 This bill requires that any open government data that is made available to the public for at least 90 consecutive days must: (1) remain machine-readable, available in an open format, and part of the worldwide public domain or, if necessary, be published with an open license; and (2) not be altered in such a way as to decrease its machine-readable nature. It shall not be a violation of such requirement to alter: (1) the digital location or format of open government data for routine asset maintenance or long-term archiving if such alteration does not decrease the open public accessibility or the machine-readable nature of the data, or (2) the contents of such data to update it or correct an error. Any substantial alteration of the data's contents shall be recorded in a log that is made available to the public in an open format along with the data. An agency may remove such data from public availability if: the agency determines that the data is too costly to maintain or does not provide sufficient value to the public, the agency publishes specified notice at least six months in advance of such removal, and the data is available for download on the worldwide public domain for at least six months before such removal. This bill shall not apply to such data that is required to be removed from public availability or altered under another provision of law.