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Gutter Slope: How Much Pitch a Gutter Needs

Gutter slope rules from DOE and two gutter makers, the drop they give for your run, where the gutter sits on the eave, and how a wrong slope is fixed.

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Facts on this page were last checked 2026-11-10.

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The sources give two figures: at least 1/16 inch of fall per foot of run, from the U.S. Department of Energy's Building America guide and the gutter maker Berger, and at least 1/4 inch per 10 feet, from Berger's copper instructions and Amerimax's installation sheet. The first is the steeper of the two. A gutter that falls less than either can hold water, and fixing the slope means re-hanging the run.

How much slope should a gutter have?

Source Figure In its words
DOE Building America 1/16 inch per foot "Install gutters along the roof eaves so they slope at least 1/16 inch per foot of run."
Berger, gutter and downspout sizing 1/16 inch or more per foot "Gutter should be pitched 1/16" or greater per foot for proper drainage."
Berger, copper gutter instructions 1/16 inch per foot; minimum 1/4 inch per 10 feet "The minimum pitch should be ¼" in every 10'."
Amerimax, installation sheet About 1/4 inch per 10 feet The string line is lowered "approximately ¼ in. for every 10 ft." toward the downspout

Berger's sizing sheet adds that a gutter can be run level for looks, but then it needs an additional downspout.

What drop does that give for your run?

Measure the run from the far end to the downspout, then read the drop.

Run to the downspout At 1/4 inch per 10 feet At 1/16 inch per foot
10 feet 1/4 inch 5/8 inch
20 feet 1/2 inch 1 1/4 inches
30 feet 3/4 inch 1 7/8 inches
40 feet 1 inch 2 1/2 inches
50 feet 1 1/4 inches 3 1/8 inches

Where should the gutter sit on the eave?

Below the line of the roof, so snow and ice can slide clear. Berger's sizing sheet sets the clearance below the extended roof line by roof pitch: 1 inch for a roof of 0 to 2 in 12, 3/4 inch for 3 to 5 in 12, 1/2 inch for 6 to 8 in 12, and 1/4 inch for 9 in 12 or steeper. The far end of a sloped run sits highest, so that is the end to check.

How can you tell the slope is wrong?

Look from the ground, or from a window above the gutter, after the rain stops. Water still standing at the end away from the downspout, or overflow there in ordinary rain while the downspout runs freely, points to the slope. Overflow at the downspout end points to a clog instead; do my gutters need cleaning? reads that from the ground. A run that dips between hangers is a sag, covered in sagging gutters.

How is a wrong slope fixed?

By re-hanging the run to a new line. Amerimax's sheet has the installer stretch a string along the fascia, lower it toward the downspout, and hang the gutter to it, with one hanger every 24 inches (every 18 inches in heavy ice and snow areas). That is gutter repair work, and a person prices it.

A worked example

A hypothetical back gutter runs 30 feet to a downspout at its left end, and water stands at the right end a day after rain. At 1/4 inch per 10 feet, the right end should sit 3/4 inch above the left; at 1/16 inch per foot, 1 7/8 inches. The owner chooses Repair, ticks "Sagging or pulling away from the house", and writes: "30 ft back run, downspout at the left; water stands at the right end after rain."

Scope and limits

Re-hanging a run to correct its slope is part of a gutter repair request. Adding a new downspout outlet, roof work and fascia carpentry are not. The figures above are makers' and DOE's recommendations, not a building code.

Get my price

Start a gutter repair request, give the run length and the end where water stands, and tick the sagging box. A person confirms the provider, scope and price in writing before payment.

Any US ZIP. No contact details until you have seen the estimate.

Sources