For pipelines constructed after April 1, 1970, each pipeline company must conduct a depth-of-cover survey in its pipeline rights of way every five years to ensure the minimum depth-of-cover as required by subsections (1) and (2) of this section has been maintained for the entire pipeline. In areas subject to erosion and subsoiling, the survey must be conducted every three years.
Location | Cover (inches) For normal excavation | Cover (inches) For rock excavation |
Industrial, commercial, and residential areas | 36 | 30 |
Crossings of inland bodies of water with a width of at least 100 ft. from high water mark to high water mark | 48 | 18 |
Drainage ditches at public roads and railroads | 36 | 36 |
Deepwater port safety zone | 48 | 24 |
Any other area | 30 | 18 |
Note: | Rock excavation is any excavation that requires blasting or removal by equivalent means. |
Wash. Admin. Code § 480-75-640
Statutory Authority: RCW 80.01.040, 80.04.060, 81.88.040. 08-12-045 (Docket PL-070974, General Order R-548), § 480-75-640, filed 5/30/08, effective 6/30/08. Statutory Authority: RCW 80.01.040 and 80.04.160. 02-18-032 (Docket No. TO-000712, General Order No. R-500), § 480-75-640, filed 8/26/02, effective 9/26/02.