Your home’s gutter system is its single most important defense against water damage. The operative word there is system. Because it’s not just the gutters that direct water away from your home, it’s also the downspouts and the drains and the various fasteners that hold everything together.

Autumn is the toughest time of year for any gutter. So, with the leaves starting to turn in most parts of the country, our experts in the Good Housekeeping Home Improvement & Outdoor Lab pulled together this checklist of red flags to watch for to make sure it’s all systems go for your gutters.

While leaves are the most common source of clogs, other debris can find its way into the gutter over the course of the year. That includes everything from branches to birds’ nests. Or if you have an older asphalt shingle roof, its protective granules can start to shed and end up in the gutter, forming a muddy layer that builds up over time.

If your home has multiple levels, it might be worth hiring a pro to clean the gutters, since the work gets dangerous the higher up you go; the average cost is around $150, according to Angi, the home services marketplace. Otherwise, you’ll need to set up a ladder and scoop out any muck that’s preventing the flow of rainwater by hand. For good measure, we recommend flushing the gutters by spraying water from a garden hose to remove smaller debris. Check that water is draining freely through each downspout to the ground below.

The gutters themselves, which are the heart of the gutter system, must be securely fastened to the house. In most cases, gutters are anchored to the fascia boards with screws or other fasteners. Walk the perimeter of the house, looking for popped fasteners, corrosion, or places where the gutter is pulling away from the house. It helps to wait for a clear day and use binoculars to inspect gutters on high roofs.

Be on the lookout for standing water in the gutters, a sign that they aren’t properly pitched. To transport water to the ground, gutters need to slope down toward the downspout at a rate of 1/4 inch for every 5 to 10 feet.

Our experts recommend gutter guards on most gutters, but they’re an absolute must if you live in a rainy region and your home is surrounded by leafy trees. In our tests, guards with fine-mesh screens proved excellent at letting rainwater into the gutter while keeping out leaves and debris. If your home is already fitted with guards, make sure none are missing or damaged during the visible inspection.

Downspouts are the vertical section of the gutter system that sends rainwater to the ground below. They should be firmly secured to the gutter and the house and not coming apart at the joints where two sections meet. Downspouts are typically held together with a combination of rivets, metal screws, and mounting straps, all of which are available at the home center or hardware store.

Also known as downspout drains, gutter drains are the pipes that lie on the ground and carry water away from the house. To do that properly, the drains need to be at least 5 feet long. That will keep rainwater from flowing back in on the house, where it can lead to flooded basements and serious foundation damage. Check that the drains are securely attached to the downspout, usually with an elbow joint and rivets. It’s also a good idea to place splash blocks at the end of the drain to prevent lawn and soil erosion.

Having written thousands of product reviews and how-to articles on all aspects of home ownership, from routine maintenance to major renovations, Dan (he/him) brings more than 20 years of industry experience to his role as the director of the Home Improvement & Outdoor Lab at the Good Housekeeping Institute. A one-time roofer and a serial remodeler, Dan can often be found keeping house at his restored Brooklyn brownstone, where he lives with his wife and kids.

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