The latest update (December 2021) of the OHIO811 Excavator Manual can be found at

It includes changes that were approved through the Marking Standard Committee in 2021.

The changes were:

  • A symbol for facilities greater than 36 inches. Page 29
  • Best Practice Note: An 18-inch tolerance zone should be respected around all above ground infrastructure. Page 16
  • Best Practice Note: Identifying markings such as facility owner, size and type shall not be used as a measuring point when establishing the tolerance zone of a buried utility. Page 16
  • Additional material type FG, Fiber Glass. Page 39

Remember to contact OHIO811 before any excavation. It’s the law.