Gutters that overflow at the outside edge during moderate rain most often indicate:

Overflow at the outside edge during moderate rain is a capacity symptom, and the question is why capacity is unavailable. Gutters are sized generously for typical rainfall, so in moderate conditions genuine undersizing is rare and obstruction is common. Debris accumulating in the trough raises the water level until it spills over the front lip; debris at the outlet or in the downspout backs water up the same way with a clean-looking trough. Both are simple to confirm and simple to correct, which is why maintenance is the first conclusion rather than replacement. The consequences of leaving it are what make it worth reporting: overflowing water lands at the foundation, defeating the gutter's purpose entirely, and standing water in the trough adds weight that pulls hangers loose and rots fascia behind them.

Overflow in moderate rain usually means available capacity is blocked rather than absent. Debris in the trough or at the downspout outlet raises the water level until it spills over the front edge.

Gutters collect roof runoff and route it to downspouts and away from the foundation. Debris accumulation in the trough or at the outlet is the most common cause of overflow, and standing water adds weight that loosens hangers and wets fascia.

Blocked Before Undersized. In moderate rain the gutter has the capacity — something is standing in the way of it.

Report the consequence as well as the cause. Overflow at the foundation is the reason it matters, and it links the gutter finding to any basement moisture noted elsewhere.

• •Recommending replacement for what is a cleaning problem
• •Reporting overflow without connecting it to foundation moisture
• •Overlooking a blocked downspout when the trough looks clear