Where gutters leak
- Seams on sectional gutters, where lengths are joined, often every 10 feet.
- Corners (miters), inside and outside, where two runs meet at an angle.
- End caps, crimped and sealed at the end of each run.
- Outlets, where the downspout drop connects to the gutter bottom.
- Fastener holes from old spikes and hangers.
- Holes and rust-through on old steel gutters.
Why they leak
- Sealant failure: sealants age in sun and with expansion and contraction. Industry guides note that sectional seams may need new sealant every few years.
- Movement: metal expands and contracts with temperature; long runs pull joints apart.
- Standing water: sags and wrong slope keep water sitting on seams.
- Ice: freezing water in seams pushes them open.
- Debris: clogs hold water against joints.
- Poor original work: joints lapped in the wrong direction, too little sealant or unsealed rivets.
How leaks are fixed
Resealing
The joint is cleaned of old sealant, dirt and oxidation, dried, and resealed with a gutter sealant compatible with the metal. On seams, the overlap should face downstream so water flows over the joint, not into it. Resealing works well on isolated leaks.
Rebuilding corners and end caps
Corners that leak repeatedly are often rebuilt: the old miter is cut out and replaced with a new one, riveted and sealed. End caps can be recrimped or replaced.
Patching holes
Small holes can be patched with a piece of matching metal and sealant. Large rusted areas usually mean the section should be replaced.
Fixing the cause
If a seam leaks because water stands on it, the slope needs correcting or a hanger added. Otherwise the new sealant will fail too. See gutter hangers explained and how to measure for gutters.
What repairs cost
Angi reports typical gutter repairs in the range of a few hundred dollars, with a national average around $390 in its recent data. Simple resealing of a few joints is at the low end; rebuilding corners, replacing sections and work on tall homes cost more. See our cost guide.
When leaks mean replacement
- Many seams leaking at once, or resealed joints failing again within a season or two
- Rust-through on steel gutters
- Sagging along long stretches
- Rotten fascia behind the gutters from years of leaks
- Gutters near the end of their typical life
Seamless gutters eliminate most seams; only corners, end caps and outlets remain. Replacing a leaky sectional system with seamless runs often ends the cycle of resealing. See seamless vs. sectional, signs you need new gutters and how long do gutters last?
Outlets and downspout connections
Outlets, where the downspout drop is riveted into the bottom of the gutter, leak when sealant fails or when debris and ice stress the joint. Outlet strainers keep debris out, and a properly flanged outlet sealed from the inside drains cleanly. If a downspout joint just below the outlet leaks, check that the upper piece fits inside the lower one so water flows down, not out. Crushed elbows at the bottom of downspouts back water up to the outlet and cause leaks there too.
Copper and soldered joints
Copper gutters are usually soldered rather than caulked. Soldered joints last much longer than sealant but can crack with movement or be damaged by ice. Repairs are made by cleaning and resoldering, which requires a sheet metal worker with copper experience. Do not patch copper with general sealants or tape, which hide the problem and stain the metal. See copper and half-round gutters.
DIY or professional?
Resealing a seam on a one-story house is a manageable DIY job for some homeowners with a safe ladder setup. Rebuilding corners, work on two-story homes and anything involving the roof edge is safer with a professional. See DIY or professional gutter installation?
Don’t ignore leaks
A leaking corner drips onto the same spot every rain: fascia and soffit rot, siding stains, the soil below erodes and water reaches the foundation. A small repair now prevents a bigger repair later. See fascia repair before new gutters.
Fascia damage from long-term leaks
A corner that has dripped for years often leaves soft fascia and soffit behind it. When the leak is repaired, press the wood with a screwdriver; if it gives, the board needs replacing, or new hangers will not hold. It is better to find this during a repair than after the gutter pulls away in a storm. See fascia repair before new gutters.
Sealants and compatibility
Gutter sealants are formulated for metal, outdoor UV and movement. General-purpose caulks often crack or peel off metal within a season. Use a sealant the gutter manufacturer recommends, and do not mix sealant types on the same joint without removing the old material first. On copper, use solder or sealants made for copper; on painted aluminum, sealant matched to the finish looks cleaner.
Expansion joints on long runs
Very long straight runs of metal gutter expand and contract enough with temperature to stress joints and pull hangers. Installers often add an expansion joint, a flexible connection, in the middle of runs longer than about 40 feet. If a long run keeps leaking at the same joints after resealing, movement may be the cause. See noisy gutters and dripping downspouts.
Leaks behind the gutter
Sometimes what looks like a seam leak is actually water running behind the gutter from the roof edge, because the drip edge is missing or the gutter hangs too low. Watch where the water comes from: if it drips from the back of the gutter or the fascia, not a joint, the fix is a gutter apron or adjusting the gutter height. See drip edge and gutter apron.
Finding the leak
Leaks are easiest to find in rain or with a hose. Run water into the gutter at the high end and watch every joint, corner and outlet. Mark drips with tape. Look for stains and rust trails on the gutter underside and fascia, which point to long-term leaks.