Start here: watch it rain
The fastest diagnosis is a look during a steady rain, from the ground, with an umbrella. Stay off the ladder in wet weather. Note:
- Where the overflow happens: along the whole run, at one spot, above a downspout, or at an inside corner
- When it happens: in every rain, or only in heavy downpours
- What the downspout outlets are doing: flowing, trickling, or dry
- Whether water drips behind the gutter, between it and the house
Take a short video if you can. It helps a pro diagnose the problem quickly.
1. Clogged gutters
Signs: Overflow along much of the run; plants or packed debris visible; overflow gets worse over time.
Fix: A thorough cleaning, then a schedule that fits your trees. See gutter cleaning in Marietta.
This is the most common cause around Marietta, where pines and hardwoods drop debris most of the year. If gutters clog between cleanings, your schedule probably needs another visit. See the Cobb County gutter cleaning calendar. Thinking about guards to stop it? Read are gutter guards worth it? and our gutter guard guide first.
2. A clogged downspout or underground drain
Signs: Overflow concentrated right above one downspout; downspout outlet dry during rain; water bubbling up at the base.
Fix: Clear the elbow or downspout; jet or snake a buried drain line; repair crushed sections. See downspout cleaning and repair.
3. Wrong pitch (slope)
Signs: Standing water in a clean gutter a day after rain; overflow at the end away from the downspout.
Fix: Re-hang the run with the correct fall toward the downspout. See gutter repair.
4. Sagging or loose sections
Signs: A visible dip mid-run; spikes backing out; gaps between gutter and fascia.
Fix: New hidden hangers, fascia repair where the wood is soft, and resetting the pitch. See gutter repair.
5. Gutters or downspouts too small
Signs: Overflow only in heavy downpours, even right after a cleaning; long runs with a single downspout.
Fix: Add downspouts, upsize downspouts, or move to 6-inch gutters. See seamless gutter replacement and sizing.
Summer thunderstorms here can deliver a lot of rain in a short time. Gutters sized for an average rain may not keep up with a downpour, especially on large or steep roof sections.
6. Roof valleys overshooting the gutter
Signs: Water shoots over the gutter at an inside corner where two roof slopes meet.
Fix: A valley splash guard (diverter) at the corner, or a larger gutter there. See gutter repair.
7. Water getting behind the gutter
Signs: Drips between gutter and house; stained or peeling fascia; soffit damage.
Fix: Add or extend the drip edge, re-hang the gutter tight to the roof edge, repair fascia. See fascia and soffit repair.
Quick diagnosis table
| What you see | Most likely cause |
|---|---|
| Overflow along the whole run, every rain | Clogged gutter |
| Overflow right above a downspout | Clogged downspout or underground drain |
| Standing water in a clean gutter | Wrong pitch or a sag |
| Overflow only in downpours, even when clean | Undersized gutters or too few downspouts |
| Water shooting over an inside corner | Roof valley overshoot |
| Drips between the gutter and the house | Water getting behind the gutter |
What to do right now
- Move water away from the foundation with a downspout extension or splash block.
- Protect anything valuable in a basement or crawlspace area that has gotten damp.
- Stay off the ladder until the weather is dry, and stay off steep or two-story roofs entirely.
- Call a pro if the gutter is sagging, pulling away, or the problem is at height.
What overflow costs you if you ignore it
- Soil erosion and washed-out beds along the house
- Damp crawlspaces and basements, and the moisture problems that follow
- Streaked siding and peeling paint
- Rotted fascia and soffit
- Water repeatedly pooling against the foundation, which you want to avoid over the long term
Questions to ask a pro
- What's causing the overflow, and can you show me?
- Will a cleaning fix it, or is there a repair needed too?
- Are my gutters and downspouts big enough for my roof?
- Would another downspout or a valley diverter help?
Not sure which cause you have? Call (678) 721‑8964 or request a free estimate. We'll connect you with an experienced, qualified local professional who can take a look.