Below are some helpful links for finding U.S. Government technical reports and data sets

Data.gov - The U.S. Government's main repository for data sets and reports.  

Science.gov - Gateway to authoritative selected science information provided by U.S. Government agencies, including research and development results.

USA.gov Statistics - Links to government statistics covering a wide range of disciplines and topics.

Catalog of U.S. Government Publications - A searchable database of federal publications that includes links to those which are full-text online.

Government Documents Search Engines - A list of U.S. government online repositories with search capabilities. 

You can also locate U.S. Government reports and documents within the WSU Libraries search catalog.

To do this, conduct a search and then use the left side navigation to limit your results to "Government Documents."