Check the pitch of your gutters
Get up on a ladder and look down the run of the gutter. Long runs of gutters are deliberately high in the middle so water flows toward downspouts at each end. Look for any peaks or valleys along the way. If these are slight, correct the problem by bending a few hangers up or down. If the problem is more serious, reset your gutter.
Calculate the drop
Take these simple steps to work out the amount of incline—or “drop”—needed:
  • Measure the length of the run of your gutter.
  • Divide the length by 10.
  • Multiply the result by .25 to get the amount of drop from one end of the gutter toward the downspout.
For example, a run of 38 feet should have a drop of about 1 inch (38 ÷ 10 = 3.8 x .25 = .95).
Reset your gutter
  • Mark the fascia. At the downspout end of the gutter, measure down from the top of the fascia and mark the correct amount of drop. Remove a hanger or two and refasten them so the top of the gutter lines up with the mark.
  • Straighten the gutter. Before adjusting the rest of the gutter, stretch a string taut above it as a guide for straightness. Reposition the hangers or add additional ones for any serious sags. Sight down the gutter to check your work.