Why pitch matters more than it sounds
A gutter that does not drain completely holds water between rains. Standing water means constant moisture against the metal and the sealed joints, added weight on the hangers, mosquito breeding in summer, and a frozen block of ice in winter that no amount of gutter capacity helps with. Most of what people call a gutter problem starts as a pitch problem.
Getting it right
On runs up to about 40 feet, pitch usually falls one way to a single outlet. Longer than that and the better approach is often to crown the middle and fall both directions to outlets at either end — that halves the distance water has to travel and keeps the visual offset from getting obvious.
The constraint is that a gutter has to look parallel to the roofline from the street while not actually being parallel. Long runs are where that tension shows up, and where crowning earns its keep.
Signs yours is wrong
- Standing water visible in the trough a day after rain.
- A tide line of grit and silt partway along the run.
- Overflow at one consistent spot in the middle rather than at the ends.
- Ice forming at one section while the rest of the run is clear.
Can pitch be corrected?
Usually, and without replacing the gutters. Re-pitching means detaching the run, re-establishing fall to the outlets, and re-hanging on hangers set at the corrected line. If the original was hung on spike-and-ferrule nails, this is the natural moment to convert to hidden hangers — the run is already down and the fasteners were going to keep working loose anyway.