A device for reducing clogging of a gutter comprises a housing which fits in a gutter over the downspout. The device contains a motor-driven grinder mechanism which grinds up waterborne leaves and other debris passing through the housing, preferably as they exit through the outlet of the housing to the downspout. The grinder mechanism preferably comprises one or more rotary type blades located above an inlet of the downspout. The device may also include a plunger mechanism which helps push water and debris in the housing through the grinder mechanism. Also, preferable the device includes a water sensor and a debris sensor for operating the motor only when both water and debris are present.