If you look closely at a gutter system the gutters have a slight pitch to them in order to help direct water downhill. So when examining gutters for correctness it is necessary to look for that slight pitch to assure they are operating correctly.
Proper Gutter System Water Flow
The way to do this is to look at where the gutter is attached to the Fascia. You want to see the gutter slightly higher on the Fascia on one side than on the other side of the gutter system.
Gutter System Components
You typically want the gutters to pitch about ½” per every 10 feet in order to keep good water flow going. Keeping in mind that if the gutters run more than 40 feet (which is not recommended) but it would be best at that point to pitch the gutters from the middle point to a downspout at each end.
Standing Water Due to Improper Pitch
The issue with gutters that are poorly pitched is a lack of proper water drainage. Especially if there is any presence of excess debris in the gutters.
Pitch would normally help the flow of water to push past small amounts of debris. But with gutters that have very little pitch the lack of extra gravity to provide an extra push can result in water very quickly become stagnant.
Gutters with no pitch will be problematic with our without debris in them. This is because with zero pitch in the gutter the water will not move to the downspouts.
Water Running Over Gutter Edge