Washington has 809 dams with recorded construction dates. The oldest dates to 1888 — 138 years ago. Washington's earliest dams were built in the 19th century, an era of westward expansion, irrigation development, and early water infrastructure. Older dams require particular attention for safety, as many were built before modern engineering standards.
| # | Dam | County | Year Built | Age | Height (ft) | Hazard | Condition |
|---|---|---|---|---|---|---|---|
| 1 | Clear Lake Dam | Chelan | 1888 | 138 yrs | 13 | High | Satisfactory |
| 2 | Clear Lake Saddle Dam | Chelan | 1888 | 138 yrs | 8 | High | Satisfactory |
| 3 | Lily Lake Dam | Chelan | 1892 | 134 yrs | 14 | High | Satisfactory |
| 4 | Macs Pond Dam | Kitsap | 1895 | 131 yrs | 39 | Low | Not assessed |
| 5 | Snoqualmie Falls | King | 1898 | 128 yrs | 19 | Low | Satisfactory |
| 6 | College Hill Reservoir | Grays Harbor | 1899 | 127 yrs | 31 | High | Poor |
| 7 | Newcastle Railroad Embankment Dam | King | 1900 | 126 yrs | 55 | High | Poor |
| 8 | Seattle City Volunteer Park Reservoir | King | 1901 | 125 yrs | 35 | High | Satisfactory |
| 9 | Prosser Diversion Dam | Benton | 1904 | 122 yrs | 9 | Low | Not assessed |
| 10 | Morse Lake Overflow Dike | King | 1904 | 122 yrs | 30 | Low | Not assessed |
| 11 | Mountain Lake Dam | San Juan | 1905 | 121 yrs | 17 | High | Fair |
| 12 | Sheep Springs Dam | Adams | 1906 | 120 yrs | 30 | Low | Not assessed |
| 13 | Three Lakes Reservoir Dam | Chelan | 1908 | 118 yrs | 9 | Low | Not assessed |
| 14 | Nine Mile | Spokane | 1908 | 118 yrs | 87 | High | Satisfactory |
| 15 | Roosevelt Reservoir | King | 1910 | 116 yrs | 23 | High | Satisfactory |
| 16 | Little Falls Spillway Dam | Lincoln | 1910 | 116 yrs | 72 | Low | Fair |
| 17 | Beaver Lake Dam | Okanogan | 1910 | 116 yrs | 10 | Low | Not assessed |
| 18 | Sasse Reservoir Dam | Okanogan | 1910 | 116 yrs | 10 | Low | Not assessed |
| 19 | Leader Lake Dam | Okanogan | 1910 | 116 yrs | 61 | High | Satisfactory |
| 20 | Leader Lake Saddle Dam | Okanogan | 1910 | 116 yrs | 16 | High | Satisfactory |
| 21 | Cranberry Lake Dam | Skagit | 1910 | 116 yrs | 13 | High | Fair |
| 22 | Little Falls Dam | Stevens | 1910 | 116 yrs | 64 | High | Fair |
| 23 | Bumping Lake Dam | Yakima | 1910 | 116 yrs | 61 | High | Not assessed |
| 24 | Conconully Dam | Okanogan | 1911 | 115 yrs | 72 | High | Not assessed |
| 25 | Tapps Lake Dike No 2a | Pierce | 1911 | 115 yrs | 9 | High | Satisfactory |
| 26 | Tapps Lake Dike No10 | Pierce | 1911 | 115 yrs | 18 | High | Satisfactory |
| 27 | Tapps Lake Dike No 6 | Pierce | 1911 | 115 yrs | 28 | High | Satisfactory |
| 28 | Tapps Lake Dike No 9 | Pierce | 1911 | 115 yrs | 15 | High | Satisfactory |
| 29 | Tapps Lake Dike No 4 | Pierce | 1911 | 115 yrs | 48 | High | Satisfactory |
| 30 | Tapps Lake Dike No 12 | Pierce | 1911 | 115 yrs | 14 | High | Satisfactory |
| 31 | Tapps Lake Dike No 2b | Pierce | 1911 | 115 yrs | 15 | High | Satisfactory |
| 32 | Tapps Lake Dike No 3 | Pierce | 1911 | 115 yrs | 15 | High | Satisfactory |
| 33 | Tapps Lake Dike No 5 | Pierce | 1911 | 115 yrs | 28 | High | Satisfactory |
| 34 | Tapps Lake Dike No 11 | Pierce | 1911 | 115 yrs | 25 | High | Satisfactory |
| 35 | Tapps Lake Dike No 8 | Pierce | 1911 | 115 yrs | 20 | High | Satisfactory |
| 36 | Tapps Lake Dike No 1 | Pierce | 1911 | 115 yrs | 18 | High | Satisfactory |
| 37 | Tapps Lake Dike No 13 | Pierce | 1911 | 115 yrs | 5 | High | Satisfactory |
| 38 | Tapps Lake Dike No 15 | Pierce | 1911 | 115 yrs | 27 | Low | Satisfactory |
| 39 | Tapps Lake Dike No 14 | Pierce | 1911 | 115 yrs | 256 | Low | Satisfactory |
| 40 | Wenas Dam | Yakima | 1911 | 115 yrs | 90 | High | Fair |
| 41 | Wapato Lake Dam | Chelan | 1912 | 114 yrs | 40 | High | Fair |
| 42 | Kachess Dam | Kittitas | 1912 | 114 yrs | 115 | High | Not assessed |
| 43 | Marshall Lake Dam | Pend Oreille | 1912 | 114 yrs | 10 | High | Fair |
| 44 | Dagger Lake Dam | Snohomish | 1912 | 114 yrs | 10 | Low | Not assessed |
| 45 | Antilon Lake Dam | Chelan | 1913 | 113 yrs | 62 | High | Fair |
| 46 | Dragoon Lake Dam | Spokane | 1913 | 113 yrs | 18 | Low | Not assessed |
| 47 | Masonry Dam | King | 1914 | 112 yrs | 230 | High | Satisfactory |
| 48 | Schweitzer Dam and Reservoir | Okanogan | 1914 | 112 yrs | 18 | High | Poor |
| 49 | Ione Mill Pond | Pend Oreille | 1914 | 112 yrs | 35 | Low | Not assessed |
| 50 | Clear Creek Dam | Yakima | 1914 | 112 yrs | 84 | High | Not assessed |