I think what they meant to say was 2000 was incredibly dry overall. The month of October 2000 logged only 0.02 inches of rain and was the middle of a very long dry streak. In total, 0.02 fell across 43 days spanning September 26 to November 9. But officially, the longest streak without rain that year was 21 days.
Their reporting in this article would agree. https://www.washingtonpost.com/weather/2024/10/22/dc-dry-streak-drought-lanina/