Scour-Critical Bridges in Washington
Washington has 501 bridges rated scour-critical by the Federal Highway Administration. These bridges have foundations that are unstable or at risk of undermining during flood events. Scour-critical doesn't mean a bridge is about to collapse — it means extra monitoring and countermeasures are in place — but these structures are priorities for repair or replacement.
How this ranking works
This state list filters to NBI scour ratings 0 through 3, then sorts by average daily traffic. It is intended to show flood-vulnerability exposure, not to label any bridge as currently unsafe.
| Bridge | County | Scour Rating | Daily Traffic | Condition |
|---|---|---|---|---|
| I-205 over SR 14 Bnrr | Clark | 3 — Serious | 160,000 | Fair |
| I-5 over Clover Creek | Pierce | 3 — Serious | 67,232 | Fair |
| I-5 over Columbia River | Clark | 3 — Serious | 65,013 | Fair |
| I-5 over Columbia River | Clark | 3 — Serious | 65,013 | Fair |
| I-5 over Stillaguamish River | Snohomish | 3 — Serious | 45,626 | Fair |
| I-5 over Stillaguamish R | Snohomish | 3 — Serious | 45,626 | Fair |
| I-5 over E Fork Lewis River | Clark | 3 — Serious | 41,939 | Poor |
| I-5 over Pilchuck Creek | Snohomish | 3 — Serious | 41,822 | Good |
| I-5 over Pilchuck Creek | Snohomish | 3 — Serious | 41,822 | Good |
| I-5 over Newaukum River | Lewis | 3 — Serious | 29,186 | Fair |
| I-5 over Newaukum River | Lewis | 3 — Serious | 29,186 | Fair |
| SR 18 over Green River | King | 3 — Serious | 28,147 | Fair |
| Sullivan Road (nb) over Spokane River | Spokane | 3 — Serious | 28,100 | Fair |
| Redmond Way over Sammamish R | King | 3 — Serious | 27,000 | Fair |
| US 101 over Chehalis River | Grays Harbor | 3 — Serious | 26,216 | Poor |
| I-82 over Overflow Channel | Yakima | 3 — Serious | 25,406 | Fair |
| I-82 over Overflow Channel | Yakima | 3 — Serious | 25,406 | Fair |
| I-5 over Skookumchuck River | Lewis | 3 — Serious | 24,769 | Fair |
| I-5 over Skookumchuck River | Lewis | 3 — Serious | 24,769 | Fair |
| I-82 over Naches River | Yakima | 3 — Serious | 24,488 | Fair |
| US 2 over Sultan River | Snohomish | 3 — Serious | 23,022 | Fair |
| I-5 over Cowlitz River | Lewis | 3 — Serious | 21,828 | Fair |
| I-5 over Cowlitz River | Lewis | 3 — Serious | 21,828 | Poor |
| US 12 over Wynoochee River | Grays Harbor | 3 — Serious | 21,466 | Poor |
| SR 303 over Port Washington Narrows | Kitsap | 3 — Serious | 21,462 | Fair |
| Main Street over Nooksack River | Whatcom | 3 — Serious | 21,350 | Fair |
| US 12 over Snake River | Asotin | 3 — Serious | 21,000 | Fair |
| SR 433 over Columbia R @ Longview | Cowlitz | 3 — Serious | 20,432 | Fair |
| SR 524 over Swamp Creek | Snohomish | 3 — Serious | 18,981 | Fair |
| I-90 over Yakima River | Kittitas | 3 — Serious | 17,681 | Fair |
| I-90 over Yakima River | Kittitas | 3 — Serious | 17,681 | Fair |
| I-90 over Kachess River | Kittitas | 3 — Serious | 17,108 | Poor |
| I-90 over Cle Elum River | Kittitas | 3 — Serious | 17,089 | Fair |
| I-90 over Cle Elum River | Kittitas | 3 — Serious | 17,089 | Fair |
| I-90 over Yakima River | Kittitas | 3 — Serious | 16,667 | Poor |
| I-90 over Yakima River | Kittitas | 3 — Serious | 16,667 | Poor |
| SR 529 over Steamboat Slough | Snohomish | 3 — Serious | 16,592 | Poor |
| SR 529 over Steamboat Slough | Snohomish | 3 — Serious | 16,592 | Fair |
| Airport Way over Snohomish R. | Snohomish | 3 — Serious | 16,383 | Good |
| SR 529 over Snohomish River | Snohomish | 3 — Serious | 16,286 | Poor |
| I-90 over Dry Creek | Kittitas | 3 — Serious | 15,974 | Poor |
| SR 3 over Johns Creek | Mason | 3 — Serious | 15,751 | Fair |
| SR 522 over Snohomish R & Tester RD | Snohomish | 3 — Serious | 15,631 | Fair |
| SR 203 over Haskell Slough | Snohomish | 3 — Serious | 15,411 | Fair |
| SR 823 over Slough & Cnty RD | Yakima | 3 — Serious | 15,105 | Fair |
| Covington-swyr RD over Jenkins Creek | King | 3 — Serious | 15,015 | Fair |
| US 12 over Scatter Creek | Thurston | 3 — Serious | 13,337 | Fair |
| US 101 over Kennedy Creek | Mason | 3 — Serious | 13,297 | Fair |
| US 101 over Kennedy Creek | Mason | 3 — Serious | 13,297 | Fair |
| US 12 over Snake River & Bnrr | Franklin | 3 — Serious | 13,260 | Fair |
| I-82 over Yakima River | Yakima | 3 — Serious | 13,121 | Fair |
| SR 525 over Possession Sound | Snohomish | 3 — Serious | 13,078 | Good |
| SR 522 over North CR & Gillman Trail | King | 3 — Serious | 12,517 | Good |
| SR 522 over North CR & Gillman Trail | King | 3 — Serious | 12,517 | Good |
| SR 203 over Drainage Overflow | Snohomish | 3 — Serious | 12,132 | Poor |
| SR 525 over Possession Sound | Island | 3 — Serious | 12,000 | Fair |
| SR 522 over North CR & Gillman Trail | King | 3 — Serious | 11,919 | Good |
| SR 18 over Holder CR Hobart RD | King | 3 — Serious | 11,615 | Good |
| SR 202 over S Fk Snoqualmie R | King | 3 — Serious | 11,531 | Fair |
| SR 500 over Lacamas Lake | Clark | 3 — Serious | 11,155 | Poor |
| SR 3 over Sherwood Creek | Mason | 3 — Serious | 10,739 | Fair |
| SR 544 over Nooksack R Overflow | Whatcom | 2 — Critical | 10,205 | Poor |
| SR 8 over Cloquallum CR | Grays Harbor | 3 — Serious | 10,124 | Good |
| SR 8 over Cloquallum CR | Grays Harbor | 3 — Serious | 10,124 | Good |
| SR 8 over E Fk Wildcat CR | Grays Harbor | 3 — Serious | 10,124 | Good |
| SR 8 over E Fk Wildcat CR | Grays Harbor | 3 — Serious | 10,124 | Good |
| US 12 over Lacamas Creek | Lewis | 3 — Serious | 10,107 | Good |
| SR 104 over Apple Tree Cove | Kitsap | 3 — Serious | 10,000 | Fair |
| NE 3 Ave. over Washougal River | Clark | 3 — Serious | 9,924 | Fair |
| SR 202 over Snoqualmie River | King | 3 — Serious | 9,740 | Poor |
| SR 160 over Puget Sound @ Fauntleroy | King | 3 — Serious | 9,721 | Fair |
| SR 160 over Puget Sound @ Fauntleroy | King | 3 — Serious | 9,721 | Good |
| SR 397 over Columbia River | Benton | 3 — Serious | 9,651 | Fair |
| SR 28 over Douglas Creek | Douglas | 3 — Serious | 9,626 | Poor |
| SR 22 over Slough Of Yakima R | Yakima | 3 — Serious | 9,615 | Fair |
| SR 17 over Lind Coulee | Grant | 3 — Serious | 9,298 | Fair |
| SR 202 over Sammamish R | King | 3 — Serious | 9,203 | Good |
| SR 7 over South Creek | Pierce | 3 — Serious | 9,080 | Good |
| I-90 over Columbia River Vantage | Kittitas | 3 — Serious | 9,077 | Fair |
| SR 500 over Lacamas Creek | Clark | 3 — Serious | 9,017 | Fair |
| SR 305 over Puget Sound @ Eagle Hrbr | Kitsap | 3 — Serious | 9,000 | Fair |
| SR 19 over Chimacum Creek | Jefferson | 3 — Serious | 8,718 | Fair |
| US 2 over Wenatchee River | Chelan | 3 — Serious | 8,705 | Poor |
| US 2 over Wenatchee River | Chelan | 3 — Serious | 8,705 | Fair |
| US 2 over Wenatchee R | Chelan | 3 — Serious | 8,705 | Fair |
| US 2 over Wenatchee River | Chelan | 3 — Serious | 8,705 | Fair |
| Locust Way over Swamp Creek | Snohomish | 3 — Serious | 8,654 | Poor |
| SE 256th ST over Soos Creek | King | 3 — Serious | 8,000 | Fair |
| SR 203 over Griffin CR | King | 3 — Serious | 7,813 | Fair |
| Old HWY 12 over Touchet River | Walla Walla | 3 — Serious | 7,642 | Fair |
| US 12 over Black River | Grays Harbor | 3 — Serious | 7,629 | Fair |
| SR 161 over Ohop Creek | Pierce | 3 — Serious | 7,615 | Fair |
| US 2 over Peshastin Creek | Chelan | 3 — Serious | 7,446 | Fair |
| US 2 over Peshastin Creek | Chelan | 3 — Serious | 7,446 | Good |
| SR 300 over Mission Creek | Mason | 3 — Serious | 7,374 | Fair |
| SR 160 over Puget Sound @ Pt Vashon | King | 3 — Serious | 7,310 | Fair |
| Kent-blk Diam RD over Big Soos Creek | King | 3 — Serious | 7,293 | Fair |
| SR 6 over Chehalis River | Lewis | 3 — Serious | 7,228 | Fair |
| NE Goodwin RD over Lacamas Creek | Clark | 3 — Serious | 7,195 | Good |
| Malaga Alcoa HWY over Squilchuck Creek | Chelan | 3 — Serious | 7,038 | Good |
| US 2 over Proctor Creek | Snohomish | 3 — Serious | 6,993 | Fair |
| US 97 over Swale Creek | Klickitat | 3 — Serious | 6,760 | Poor |
| US 2 over Anderson Creek | Snohomish | 3 — Serious | 6,701 | Fair |
| US 12 over Silver Creek | Lewis | 3 — Serious | 6,690 | Good |
| SR 162 over S Prairie Creek | Pierce | 3 — Serious | 6,643 | Good |
| US 12 over Klickitat Creek | Lewis | 3 — Serious | 6,548 | Good |
| SR 109 over Humptulips River | Grays Harbor | 3 — Serious | 6,510 | Fair |
| W North Bend Way over S Fork Snoqualmie River | King | 3 — Serious | 6,500 | Fair |
| US 2 over Stream | King | 3 — Serious | 6,441 | Fair |
| US 2 over S Fk Skykomish River | Snohomish | 3 — Serious | 6,408 | Poor |
| US 97 over Wanity Slough | Yakima | 3 — Serious | 6,219 | Good |
| US 97 over Wanity Slough | Yakima | 3 — Serious | 6,219 | Poor |
| US 97 over Columbia River | Klickitat | 3 — Serious | 6,212 | Fair |
| SR 105 over Johns River | Grays Harbor | 3 — Serious | 6,124 | Fair |
| Umptanum Road over Yakima River | Kittitas | 3 — Serious | 6,083 | Fair |
| SR 104 over Puget Sound @ Edmonds | Snohomish | 3 — Serious | 5,870 | Fair |
| US 12 over Cedar Creek | Grays Harbor | 3 — Serious | 5,851 | Fair |
| Aplets Wy over Wenatchee River | Chelan | 3 — Serious | 5,800 | Poor |
| US 12 over Pacific P L Tailrace | Yakima | 3 — Serious | 5,794 | Good |
| US 2 over Anthracite Creek | King | 3 — Serious | 5,782 | Poor |
| US 97 over Bonaparte CR | Okanogan | 3 — Serious | 5,771 | Good |
| SR 970 over Teanaway R | Kittitas | 3 — Serious | 5,741 | Fair |
| US 2 over Creek | King | 3 — Serious | 5,692 | Fair |
| Malaga-alcoa HWY over Stemilt Cr. | Chelan | 3 — Serious | 5,578 | Fair |
| US 97 over Little Klickitat River | Klickitat | 3 — Serious | 5,532 | Fair |
| Wandermere Road over Little Spokane River | Spokane | 3 — Serious | 5,394 | Fair |
| SR 542 over Kendall Creek | Whatcom | 3 — Serious | 5,312 | Fair |
| Talley Way over Coweeman River | Cowlitz | 3 — Serious | 5,285 | Fair |
| SR 14 over Lawton Creek | Clark | 3 — Serious | 5,270 | Good |
| SR 507 over Deschutes River | Thurston | 3 — Serious | 5,190 | Fair |
| US 12 over Touchet River | Walla Walla | 3 — Serious | 5,054 | Fair |
| SR 20 over Baker River | Skagit | 3 — Serious | 5,032 | Poor |
| SR 18 Ramp over Holder CR | King | 3 — Serious | 5,021 | Fair |
| SR 9 over W Fk Nookachamps Creek | Skagit | 3 — Serious | 4,825 | Good |
| SR 4 over Abernathy Creek | Cowlitz | 3 — Serious | 4,787 | Fair |
| SR 20 over H W Channel Methow R | Okanogan | 3 — Serious | 4,775 | Good |
| 244th AVE SE over Newaukum Creek | King | 3 — Serious | 4,723 | Fair |
| SR 160 over Puget Sound @ Pt Vashon | King | 3 — Serious | 4,675 | Good |
| SR 530 over Deer Creek | Snohomish | 3 — Serious | 4,618 | Good |
| US 12 over Touchet River | Columbia | 3 — Serious | 4,556 | Good |
| SR 165 over Wilkeson Creek | Pierce | 3 — Serious | 4,521 | Good |
| US 97 over Okanogan River | Okanogan | 3 — Serious | 4,504 | Fair |
| US 101 over Smith Creek | Pacific | 3 — Serious | 4,478 | Fair |
| US 101 over Elkhorn CR | Pacific | 3 — Serious | 4,478 | Fair |
| SR 129 over Asotin Creek | Asotin | 3 — Serious | 4,450 | Good |
| US 101 over Salmon CR | Grays Harbor | 3 — Serious | 4,290 | Fair |
| US 97 over Marion Drain Canal | Yakima | 3 — Serious | 4,257 | Good |
| Naches Rd. S. over Naches River | Yakima | 3 — Serious | 4,150 | Poor |
| Woodcock Road over Dungeness River | Clallam | 3 — Serious | 4,147 | Fair |
| SR 9 over N Fk Nooksack River | Whatcom | 3 — Serious | 4,066 | Fair |
| SR 107 over Chehalis River | Grays Harbor | 3 — Serious | 4,044 | Fair |
| US 101 over Sol Duc River | Clallam | 3 — Serious | 4,018 | Fair |
| US 97 over Kusshi CR | Klickitat | 3 — Serious | 4,013 | Poor |
| SR 503 over Chelatchie Creek | Clark | 3 — Serious | 4,008 | Good |
| SR 503 over Cedar Creek | Clark | 3 — Serious | 4,008 | Good |
| US 101 over Indian Creek | Clallam | 3 — Serious | 3,925 | Poor |
| Sr104 over Apple Tree Cove | Kitsap | 3 — Serious | 3,866 | Fair |
| US 101 over Lake Creek | Clallam | 3 — Serious | 3,805 | Fair |
| Ferry Traffic over Puget Sound @ Seattle | King | 3 — Serious | 3,800 | Fair |
| SR 141 over Rattlesnake Creek | Klickitat | 3 — Serious | 3,793 | Good |
| SR 173 over Columbia R | Douglas | 3 — Serious | 3,767 | Fair |
| SR 20 over Chewuch River | Okanogan | 3 — Serious | 3,696 | Poor |
| SE 400th ST over Newaukum Creek | King | 3 — Serious | 3,694 | Fair |
| SR 160 over Puget Sound @ Southworth | Kitsap | 3 — Serious | 3,681 | Good |
| SR 304 over Sinclair Inlet | Kitsap | 3 — Serious | 3,600 | Fair |
| SR 500 over Washougal River | Clark | 3 — Serious | 3,589 | Fair |
| SR 530 over Boulder Creek | Snohomish | 3 — Serious | 3,586 | Good |
| US 101 over Big Quilcene River | Jefferson | 3 — Serious | 3,525 | Poor |
| SR 112 over Salt Creek | Clallam | 3 — Serious | 3,493 | Fair |
| Old HWY No. 9 over Prairie Creek | Thurston | 3 — Serious | 3,433 | Fair |
| SR 20 over Ship Hbr/guemes Channel | Skagit | 3 — Serious | 3,227 | Poor |
| SR 20 over Ship Hbr/guemes Channel | Skagit | 3 — Serious | 3,227 | Fair |
| US 101 over Indian CR | Clallam | 3 — Serious | 3,200 | Fair |
| SR 305 over Puget Sound @ Eagle Hrbr | Kitsap | 3 — Serious | 3,052 | Fair |
| Case Road over Beaver Creek | Thurston | 3 — Serious | 3,040 | Fair |
| US 101 over Duckabush River | Jefferson | 3 — Serious | 2,967 | Fair |
| Seven Mile Road over Deep Creek | Spokane | 3 — Serious | 2,901 | Fair |
| Alder Cutoff RD E over Mashel River | Pierce | 3 — Serious | 2,900 | Fair |
| SR 7 over Nisqually R Overflow | Lewis | 3 — Serious | 2,872 | Good |
| SR 401 over Naselle R | Pacific | 3 — Serious | 2,839 | Good |
| US 101 over Little Quilcene River | Jefferson | 3 — Serious | 2,792 | Fair |
| Case Road SW over Scatter Creek | Thurston | 3 — Serious | 2,751 | Fair |
| US 12 over Cowlitz River | Lewis | 3 — Serious | 2,712 | Fair |
| US 12 over Davis Creek | Lewis | 3 — Serious | 2,712 | Good |
| US 12 over Cowlitz R Overflow | Lewis | 3 — Serious | 2,712 | Good |
| SR 823 over Yakima River | Yakima | 3 — Serious | 2,678 | Fair |
| US 101 over Fulton Creek | Jefferson | 3 — Serious | 2,667 | Fair |
| US 12 over Lake CR | Lewis | 3 — Serious | 2,666 | Fair |
| Mountain Loop Hwy. over Twentytwo Creek | Snohomish | 3 — Serious | 2,662 | Fair |
| US 12 over Johnson CR | Lewis | 3 — Serious | 2,655 | Fair |
| SR 160 over Puget Sound | King | 3 — Serious | 2,635 | Fair |
| Ocean Beach Road over Berg Slough | Grays Harbor | 3 — Serious | 2,622 | Poor |
| SR 20 Extension over Friday Hbr-san Juan Chan | San Juan | 3 — Serious | 2,587 | Good |
| SR 6 over Jones Creek | Lewis | 3 — Serious | 2,524 | Good |
| SR 503 over Chelatchie Creek | Clark | 3 — Serious | 2,508 | Good |
| US 12 over Coal Creek | Lewis | 3 — Serious | 2,494 | Poor |
| SR 20 over Rocky Creek | Skagit | 3 — Serious | 2,492 | Fair |
| Little Spokane Dr. over Little Spokane River | Spokane | 3 — Serious | 2,456 | Fair |
| Ocean Beach Road over Copalis River | Grays Harbor | 3 — Serious | 2,446 | Poor |
| SR 7 over Tilton River | Lewis | 3 — Serious | 2,351 | Poor |