The median income in Johnsville has shown volatility over the past decade. It peaked at $74,227 in 2018 and reached its lowest point at $62,280 in 2022, with a general downward trend since 2018. This downward trend coincides with a slight increase in the white population percentage and a decrease in other racial groups. The population has fluctuated between approximately 1,300 and 1,800 residents over the decade, suggesting a relatively stable community size despite economic fluctuations.

Johnsville's "Low Diversity" classification is atypical for California, which is known for its diverse population. The median income has generally remained above $60,000, which is close to the national median household income. The stability of the racial composition over a decade is noteworthy, especially in a state known for demographic changes. This could indicate that Johnsville is a relatively isolated or self-contained community. The recent downward trend in median income, particularly since 2018, may reflect broader economic challenges that have affected many communities nationwide.

Johnsville presents a picture of a stable, predominantly white community with moderate income levels. While it has experienced some economic fluctuations, its demographic composition has remained largely unchanged over the past decade, setting it apart from the more diverse trends often seen in California.