Other reasons for overflow problems might be that your gutters are not properly sloped or sections of the gutter configuration have sagged. Gutters must gradually slant in an even line toward the downspout to allow rainwater to drain. Standing water can cause sagging, rust and corrosion, so proper outflow is crucial. Again, simply take a good look at the shape of your gutters. If something seems amiss, call in a professional or consult the online how-to article, Repairing Damaged Gutters, from the This Old House Web site.

Sometimes gutter troubles do not involve overflow, but are the result of leak or connection issues. If your gutter has a crack in it, you can likely do the repairs yourself, as long as your roof is not dangerously high. Another problem you might observe is water running from the roof, bypassing the gutters altogether, and flowing down behind them. If this is the case, your gutter's fastenings have likely become dislodged from the house. Some do-it-yourself mending might also prove adequate in this instance. See the Repairing Damaged Gutters  article mentioned above for details. Alternatively, the trouble might be the result of your roof shingles not providing sufficient overhang to the gutters. To repair this sort of defect, consult with a roof specialist, as you will likely need additional edging installed.