Rain Gutters that Trap Water: Easy Fixes

Gutters that trap pools of water need to be adjusted so they’re inclined at ¼-inch of slope for every 10 feet of run.

Long runs of gutters are purposely raised in the middle so water flows to either end. Image: dmr-gutters.com

To prevent gutters from trapping stagnant pools of water, they need to be pitched toward the downspouts for proper flow. That means an incline of ¼-inch of slope for every 10 feet of gutter. Set at the correct incline, your gutters should drain completely.

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.