5-Inch vs. 6-Inch Gutters: Which Size Is Right for Your Treasure Valley Home?

If you're getting quotes for new gutters, you've probably noticed the size question comes up fast: 5-inch or 6-inch? A lot of gutter content treats 6-inch as the automatic upgrade — but for most homes in the Treasure Valley, it isn't necessary. The honest answer depends on your roofing material and pitch, not a blanket rule.

Here's how we actually make that call on a Treasure Valley roofline, and why we don't push 6-inch on every quote.

What the Extra Inch Actually Buys You

The number in "5-inch" or "6-inch" refers to the width across the top of the gutter trough — and that extra inch does add real capacity:

• 5-inch K-style gutters hold roughly 1.2 gallons of water per linear foot.
• 6-inch K-style gutters hold roughly 2 gallons per linear foot — about 40% more capacity.

One thing worth clearing up: a bigger gutter doesn't automatically mean a bigger downspout. We size 6-inch residential systems with standard downspouts — a 3x4-inch downspout is something we reserve for commercial-scale applications, not a typical Treasure Valley home. So the capacity difference between 5-inch and 6-inch on a residential job comes mostly from the trough itself, not a bigger downspout doing extra work.

Why Most Treasure Valley Roofs Don't Need 6-Inch

Gutter sizing isn't a style choice, and it isn't something to upsize "just in case" either. On a standard asphalt shingle roof with a typical pitch — which describes most homes across Boise, Meridian, Eagle, Nampa, and Kuna — a properly installed 5-inch system handles Treasure Valley storms just fine. In our own installs, 6-inch only ends up being the right call on somewhere around 15–20% of jobs.

What actually pushes a home toward 6-inch is narrower than a lot of gutter content suggests:

• Metal roofing. Metal sheds water much faster than shingles, which increases the volume hitting the gutter during a storm.
• Tile roofing. Like metal, tile moves water off the roof quickly and in larger surges than asphalt shingle.
• A very steep roof pitch. A steep enough pitch sends water into the gutter fast enough that a 5-inch trough can genuinely fall behind.

Outside of those specific cases, sizing up to 6-inch is rarely doing much for a typical shingled, moderately pitched Treasure Valley roof — and it adds cost without a real benefit.

The Real Fix for Overflow Is Usually Installation, Not Size

If you've had gutters overflow during a storm, it's tempting to assume the fix is a bigger gutter. Around here, that's often not actually the problem. A gutter hung with the correct pitch and proper hanger spacing moves water to the downspout the way it's supposed to — and when that's done right, most Treasure Valley homes don't need 6-inch gutters or heat tape to keep up.

Overflow is much more commonly a sign of a gutter that's pitched wrong, sagging between hangers, or under-hung for the roof it's catching — not a sign that the trough itself is too small. Before sizing up, it's worth having someone check the installation itself.

Cost Difference: Is 6-Inch Worth the Upgrade?

The price gap between the two sizes is smaller than most homeowners expect — typically $0.50 to $1.00 more per linear foot for 6-inch over 5-inch. That's a modest increase, but on the roofs where 6-inch genuinely isn't doing anything extra, it's money that doesn't need to be spent.

Where the upgrade does earn its keep is on the roofs above — metal, tile, or a genuinely steep pitch — where the added capacity is solving a real problem instead of a hypothetical one.

Which Size Should You Choose?

5-inch gutters make sense if:

• You have a standard asphalt shingle roof with a typical, walkable pitch
• This describes most homes in the Treasure Valley — and covers roughly 80–85% of the homes we install on
• Your gutters are hung correctly, with the right pitch and hanger spacing, so water reaches the downspout the way it should

6-inch gutters make sense if:

• You have a metal roof
• You have a tile roof
• Your roof has a very steep pitch

Get an Honest Recommendation, Not an Upsell

Gutter sizing isn't something to guess at from a general rule of thumb, and it isn't something we default to the bigger option on either. Gutters R Us measures roofline length, pitch, and roofing material for every seamless gutter installation across Boise, Meridian, Eagle, Nampa, and Kuna, and recommends the size that actually fits your home — which is 5-inch for most Treasure Valley roofs.

Every installation is backed by a 5-year labor warranty and 25-year warranty on metal materials.

Not sure which size fits your home? Request a free estimate or call (208) 941-4641 for a roofline assessment.

FAQs: Gutter Sizing

How do I know if my current gutters are the wrong size?

Frequent overflow during heavy rain is the most common sign homeowners point to — but around here, that's usually an installation issue rather than a sizing issue. Before assuming you need to size up, it's worth having the pitch and hanger spacing checked, since gutters that are hung correctly rarely overflow regardless of size.

Can I upgrade from 5-inch to 6-inch gutters without replacing the whole system?

In most cases, upgrading gutter size means replacing the full run, since the fascia brackets and downspouts are sized to match. It's usually done as part of a full gutter replacement.

Do 6-inch gutters cost significantly more to install?

Not usually. The material cost difference is typically $0.50 to $1.00 more per linear foot. Since 6-inch is only the right fit for a minority of Treasure Valley homes, that's a cost most homeowners with a standard shingle roof don't need to take on at all.

Are 6-inch gutters better for every home?

No — in fact 6-inch is the exception, not the rule, around here. It only ends up being the right call on roughly 15–20% of the homes we work on, almost always because of a metal roof, a tile roof, or a very steep pitch. A standard shingled roof with typical pitch does fine with 5-inch.

Do I need a 3x4 downspout with 6-inch gutters?

Not for a residential home. A 3x4-inch downspout is something we reserve for commercial-scale applications. Residential 6-inch gutter systems are typically paired with a standard downspout, so the added capacity comes from the trough itself.

Will 6-inch gutters or heat tape fix my overflow or ice problems?

Usually not on their own. If gutters are hung with the correct pitch and proper hanger spacing, most Treasure Valley homes don't need heat tape or 6-inch gutters to stay ahead of overflow or ice buildup. It's worth ruling out an installation issue first.

Gutters R Us is a locally owned, female- and veteran-owned, licensed and insured gutter company serving Boise and the greater Treasure Valley, ID — specializing in seamless gutter installation, permanent JellyFish Lighting installation, soffit and fascia installation and repair, and micromesh gutter guard systems.