Gutters, Downspouts & Drainage: Your Home’s First Line of Defense

Most homeowners think of gutters as an accessory. Your home inspector thinks of them as a safety feature — because the single most common source of expensive home damage we find in Treasure Valley homes is water that wasn’t moved away from the house. During even a modest rainstorm, your roof collects hundreds of gallons of water per inch of rainfall. The gutter system’s entire job is to get all of that water away from your foundation.

When it fails — or was never fully installed — that water soaks the soil against your foundation. In our climate, that saturated soil freezes and expands in winter, pressing against foundation walls year after year. Foundation repairs caused by poor drainage can easily run into tens of thousands of dollars, all traceable to a part of the home that costs comparatively little to install and maintain.

A properly installed gutter slopes toward its downspout at roughly one inch of fall over every 17 feet of run — enough to keep water moving without looking crooked from the street. Gutters that hold standing water after a storm are either sloped wrong, sagging, or clogged.

The easiest maintenance habit we know: clean your gutters twice a year, when the clocks change. Spring cleaning clears the seeds and blossoms; fall cleaning clears the leaves before snow locks them in. A clogged gutter isn’t just ineffective — the trapped water and debris are heavy enough to pull the gutter loose from the fascia, and the overflow dumps concentrated streams of water exactly where you don’t want them.

As a rule of thumb, a gutter run needs one downspout for about every 35 feet of gutter. Too few downspouts and the gutter overflows in heavy rain no matter how clean it is. A missing downspout is actually worse than a missing gutter — the gutter collects water from the whole roof plane and then pours it out in one concentrated spot.

Two details matter most:

• Discharge distance. Water should be carried at least six feet away from the foundation before it’s released. Downspout extensions are cheap; buried drain lines are tidier. A downspout that ends at the foundation is just an efficient foundation-soaking machine.
• Upper-story downspouts. A second-floor downspout should never discharge directly onto a lower roof — the concentrated stream wears out shingles years early. It should tie into a lower gutter or continue down in a leader pipe.

Where a downspout or extension releases water, an 18-to-24-inch splash block slows the stream and prevents erosion. Put one under your outdoor faucets too — we regularly find foundation staining and erosion behind hose bibs where a dripping connection has run down the wall for years.

Finally, the ground itself should carry water away: aim for a slope of about one inch per foot for the first six feet away from the foundation. Watch out for landscaping edging and mulch beds that act as little dams, holding roof water in a moat against your house. If you garden, a rain barrel at a downspout turns the problem into free irrigation water.

Gutters, downspouts, grading, and drainage are among the first things we evaluate on every inspection — because water is the number one enemy of every home.

Poor drainage is the leading cause of the moisture problems behind mold growth — learn more on our Mold Inspection & Testing page. Getting your home ready to sell? See Preparing Your Home for an Inspection, or browse all our Homeowner Resources.

Whether you’re looking to buy or sell a residential or commercial property, you need a trusted and reliable home inspector who can provide you with the information you need to make an informed decision.

Don’t let unseen problems turn into costly headaches down the road – contact us today to schedule your inspection and get the peace of mind you deserve.