The Knox County Board the responsible governing body for the Galesburg Sanitary District and the Knox County Department of Public Health. Some minutes (back to Dec. 2002) from Board meetings are posted on their website.
The website of the City of Galesburg Town Assessor has a database of residential property values. Look up a residence by address to find out the latest assessed value of that property. This kind of data could point out relative poverty/income levels in an area.