To find the y-intercept of the function \( y = 30(0.85)^x \), we evaluate the function at \( x = 0 \).
The y-intercept occurs where the graph intersects the y-axis, which corresponds to the value of \( y \) when \( x = 0 \):
\[ y = 30(0.85)^0 \]
Since any number raised to the power of 0 is 1, we have:
\[ y = 30 \cdot 1 = 30 \]
Thus, the y-intercept of the function \( y = 30(0.85)^x \) is:
\[ \boxed{30} \]