What those black stripes actually are, and why a house wash will not move them
The dark vertical striping that Savannah gutters pick up is not dirt sitting on the surface, and that is why it refuses to rinse off. On an aluminum gutter the factory finish is anodized or painted, and when salt air off the marsh and the river combines with Lowcountry humidity, the metal and the finish oxidize and weather unevenly. The runoff channeling down the face of the gutter from the roofline, where water lingers against the drip edge, etches a separate line of that oxidation below each seam and downspout. What you are seeing is a chemical change in the surface, not a coating of grime, so a pressure wash aimed at the stripes simply wets them and sends the water to the ground while the stain stays put. Brightening is the treatment that reverses it - a cleaner matched to metal oxidation applied to the face, allowed to dwell long enough to break the bond, then agitated and rinsed so the factory tone returns.
The difference between cleaning the inside and brightening the outside
These are two separate jobs that Savannah owners routinely collapse into one, and the distinction changes what you book. Gutter cleaning removes the leaves, oak catkins, pine needles, and sediment that collect inside the trough and keep water from draining to the downspout - it is about keeping the system flowing. Gutter brightening is about the outside face that everyone looking at the house from the street sees. A gutter can be perfectly clear inside and still look years old because the exterior is streaked and chalky, and a gutter can be freshly brightened and still be clogged up top. If both are true at your house, they are separate scope lines on the same visit, and a crew that quotes one number for "gutters" without asking which one you mean has not priced the job you need.
Where in Savannah it shows up first, and why
The salt load is not even across town, so the staining is not even either. Homes closest to the open water of the Wilmington and Bull Rivers, and the marsh-front streets of Wilmington Island and Isle of Hope, carry the heaviest salt aerosol and oxidize the fastest - the black stripes there can read as damage from the curb within a few seasons. On Tybee, the constant sea air does the same work in less time. Inland, the picture is gentler but still coastal: the salt that drifts up from the Savannah River toward the Historic District and the older neighborhoods around Ardsley Park and the Victorian District keeps gutters oxidizing faster than they would a few counties north, and the newer subdivisions out in Pooler and Richmond Hill see a lighter but steady version of the same film. The crisp white gutters that are so common on newer construction show every stripe earliest; the dark bronze and brown finishes hide the oxidation longer, which is why a bronze-guttered house can look fine to a passerby and still be worth brightening up close.
Why we work by hand instead of leaning a wand on it
A gutter is thin aluminum, usually fastened to the fascia and edged against the roofline, and it has no business under high pressure. A wand forced up against the face can dent the metal, bend the drip edge, or drive water up behind the gutter and into the fascia board where it sits and rots. So brightening is hand-applied detail work: we lay the oxidation cleaner onto the affected faces, give it the dwell time the coastal buildup actually needs rather than a token minute, then lightly agitate the worst of the stripes with a soft tool and rinse at gentle pressure. We mask or soak the plantings below before we start and keep the rinse directed, because on a compact Savannah lot the bed line and the walkway sit right where the runoff goes. It is slower than pointing a machine at it, and it is the difference between a clean surface and a scarred one.
When brightening is the fix, and when the honest answer is replacement
Brightening restores the surface of an otherwise sound gutter. It is the right call when the metal is intact, the seams are holding, and what is bothering you is the streaked, chalky face that makes the roofline look tired from the street. It is not a fix for gutters that are genuinely failing. If the aluminum is pitted or corroded all the way through, if the seams are separated and leaking onto the siding, if sections are pulling away from the fascia, or if a storm has dented or kinked the runs, no amount of cleaning puts that right - the money belongs in repair or replacement, and we would rather tell you that before we book than take the work knowing it cannot deliver. If we get up there and find a few corroded-through spots in an otherwise good system, the straight answer is usually to brighten what is sound now and replace the failing sections, which is cheaper than a full re-roof of the gutter line.
How often, and what keeps it from coming back fast
There is no single calendar that fits every Savannah gutter, but the honest benchmark is tied to salt exposure rather than the date. Marsh-front and river-front homes, and anything on the islands or Tybee, generally want the faces brightened every year to two years to stay ahead of the oxidation, because the salt keeps laying down. Homes on open inland lots can stretch that toward every two to three years. The cheapest version of this work is the regular one: oxidation that has not sat through several seasons comes off gently and cheaply, while striping that has been left for years has bonded deeper and takes more product and more time to lift. Whatever the cadence, brightening belongs in the same season as the rest of the exterior work, which is why most Savannah owners fold it into the same visit as their house washing rather than booking a separate trip for the gutters alone.
Where to start if you are not sure yours need it
The cheap way to find out whether brightening will pay for itself is a look at the gutters on a dry day and a pass of your hand across the face. If the surface is smooth and the dark is sitting on top, that is a film a wash might catch. If the face feels chalky or you can see the stripes etched below the drip edge and around each seam, that is oxidation and brightening is the job. If you can feel pitting or see metal breaking through in places, that is the replacement conversation. Send us a photo of the worst run from the ground and we will tell you which of the three you are looking at before we schedule anything.
