Spokane County, WA Fence Regulations: Retaining Walls (2026)
Key Facts
- Right-of-way wall standard
- AASHTO Standard Specifications for Highway Bridges
- Block wall standard
- NCMA Technical Report 127
- Private-lot permit trigger
- unsupported excavation over 5 feet
- Plan review
- separate fee applies to retaining walls
- Approval authority
- county engineer (ROW); building official (private lot)
- Governing sections
- SCC 9.75.510 and 3.10.020
Summary
Spokane County regulates retaining walls two ways: any wall inside county road right-of-way must be engineered to AASHTO bridge standards under Section 9.75.510, while a wall on private property needs a grading or building permit whenever it creates an unsupported excavation over five feet high under Section 3.10.020.
SCC 3.10.020(d)(2): An excavation below finished grade for basements and footings of a building, retaining wall or other structure authorized by a valid building permit. This shall not exempt any fill made with the material from such excavation or exempt any excavation having an unsupported height greater than five feet (one thousand five hundred twenty-four mm) after the completion of such structure.
SCC 9.75.510: (a)Analysis and design of retaining walls and other structures constructed within county right-of-way and/or maintained by Spokane County shall conform to the requirements of the current edition of the "Standard Specifications for Highway Bridges," AASHTO. Plans and structural computations shall be submitted for approval of the county engineer/public works director before construction begins.(b)Mortarless concrete block retaining walls shall be designed and constructed in accordance with the National Concrete Masonry Association Technical Report 127 (NCMA TR127).
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 63).
Full Breakdown
510(a) requires that analysis and design of retaining walls and other structures constructed within county right-of-way and/or maintained by Spokane County conform to the current edition of the Standard Specifications for Highway Bridges, AASHTO, and that plans and structural computations be submitted to the county engineer/public works director for approval before construction begins. 510(b) requires them to be designed and constructed in accordance with National Concrete Masonry Association Technical Report 127 (NCMA TR127). 10. 020(d)(2) withdraws that exemption once the excavation leaves an unsupported height greater than five feet after the wall is finished, meaning taller walls need a separate grading permit on top of any building permit.
020(h) states that separate plan review fees apply to retaining walls or major drainage structures, on top of standard grading permit, plan review, and inspection fees. 020(l) still apply, keeping the top of a cut or toe of a fill slope back from the property line by a distance tied to the slope's height.
Violations & Fines
Retaining walls built without the required grading or building permit fall under the same unlawful-construction language as any other Title 3 structure: Section 3.02.020(a) bars construction without first obtaining a separate permit, so an unpermitted wall over five feet of unsupported excavation can draw a stop-work order and a requirement to obtain permits retroactively. In the right-of-way, a wall built without county engineer approval under Section 9.75.510(a) is not a county-maintained improvement, and the property owner bears liability for it.
Frequently Asked Questions
Do I need a permit to build a retaining wall on my property in Spokane County?
What standard governs a retaining wall in a Spokane County road right-of-way?
Are concrete block retaining walls held to a different standard?
Will I pay an extra fee for a retaining wall permit?
Sources & Official References
Other rules in Spokane County
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