SR 20 over Little Boulder Creek
Okanogan County, Washington · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- SR 20 over Little Boulder Creek in Okanogan County, Washington, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 8 (very good condition) on the 0-9 scale.
- It was built in 2005, making it 20 years old at the 2025 inventory.
- It carries about 1,280 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 75 of the 161 inventoried bridges in Okanogan County rated good (46.6%); 12 (7.5%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated July 2021, on a 48-month routine inspection cycle.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (48.57003, -120.38089)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Culvert | 8 | 8 | Very good condition |
Bridge details
| Structure | Steel culvert |
| Length | about 28 ft |
| Location | 18.8 E Chelan Co |
| NBI structure number | 0016979A0000000 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | July 2021 |
| Inspection interval (item 91) | 48 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Washington department of transportation.
Busiest bridges in Okanogan County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 97 over Okanogan River | 1964 | 8,828 | Fair |
| US 97 over SR 155 | 1964 | 8,828 | Poor |
| US 97 over Gn Rr-county Road | 1964 | 7,453 | Good |
| SR 155 Spur over Okanogan River | 1923 | 5,987 | Fair |
| US 97 over Bonaparte CR | 1957 | 5,771 | Good |
| US 97 over Watson Draw | 1965 | 5,644 | Poor |
All bridges nearby: Okanogan County, WA bridge conditions · every bridge in Okanogan County · Washington bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.