Have you tried creating tables on disk from the the table views? # Make a tableview of impervious surfaces from the query.
query = """"Material" IN ('concrete', 'asphalt', 'wood', 'rubber', 'artificial', 'greenasphalt', 'blueasphalt','redasphalt')"""
arcpy.MakeTableView_management("Surfaces\\allSurfaces", "impsurfaces", query)
# Create a .dbf table in current workspace from the table view.
arcpy.CopyRows_management("impsurfaces", "impsurfaces.dbf")
# Make a table view containing all surfaces.
arcpy.MakeTableView_management("Surfaces\\allSurfaces", "surfacetotals")
arcpy.CopyRows_management("surfacetotals", "surfacetotals.dbf")
# Summarize to get total imp surface by property
arcpy.Statistics_analysis("impsurfaces.dbf", "Sewer", [["Shape.area", "SUM"]], "Property")
# Summarize to get total park area by property
arcpy.Statistics_analysis("surfacetotals.dbf", "Parksizes", [["Shape.area", "SUM"]], "Property")
#join the tables so we can do some calculations.
arcpy.JoinField_management("Sewer", "Property", "Parksizes", "Property", "SUM_Shape_area")