Water overflowing or backing up toward the roof. The cause is almost always leaves, mud, or debris clogging the gutter or downspout. The fix takes 10-20 minutes.
Start where water spills over. Use your gloved hand to remove leaves, mud, sticks, and grit. Pull debris toward you — don't push it down the gutter.
Run a hose through the cleared section. If water backs up, the downspout is clogged. Spray water down from the top, tap the outside to loosen debris, then spray upward from the bottom to force the clog out.
If water pools in the gutter instead of flowing toward the downspout, adjust the hangers so the gutter slopes slightly toward the outlet.