The customer is responsible for all digging/backfilling the electric service trench. The following requirements are needed prior to the PUD energizing service:

  • Customer is responsible to dig up to the PUD source (i.e. pole, transformer, pedestal, junction box, etc).
  • Trencher/ditch witch is not acceptable
  • Any trenching done within public right-of-way or on property not owned by the customer, only a PUD approved licensed and bonded contractor, hired by the customer, may perform work within the public right-of-way or on neighboring property and must adhere to the standards of the local jurisdiction.
  • Trench must be 36 inches to 48 inches (3 feet to 4 feet) deep, measured from the surface to the top of the conduit, by 1 foot wide (minimum). Any turns/bends in the trench will require a 2-foot width.
  • Trench shall be as straight as possible.
  • Trench shall be free of trash and be thoroughly compacted throughout.
  • Native backfill containing large rocks, paving materials, cinders, large or sharply angular substance, or corrosive material shall not be placed back into the trench.
  • Contact Skamania PUD once the trench is open. Trenching should only be done after the electrical inspection has taken place and the meter base, riser conduit and the 36-inch radius sweep have been installed.
  • Schedule the trenching so the trench is open for the shortest time to avoid creating a public hazard and minimize the possibility of the trench collapsing


Conduit SizeAverage Diameter SizeMinimum Depth (from surface to bottom of conduit)
2.5 inch Conduit2.875 inches (2⅞ inches)36 inches + 2⅞ inches= 38⅞ inches
3 inch Conduit3.5 inches (3½ inches)36 inches + 3½ inches= 39½ inches
4 inch Conduit4.5 inches (4½ inches)36 inches + 4½ inches = 40½ inches

Note: Customer-owned electric services on the customer (load) side of the meter fall under the jurisdiction of the Washington State Department of Labor and Industries. It is the customer’s responsibility to adhere to each governing body’s specifications in regards to trenching, conduit, wire, etc.