Quick Answer:
If a basement drain starts backing up while you’re clearing melting snow, the most common causes are surface meltwater overwhelming exterior drains, blocked downspout extensions buried by snow, or a sump pump that can’t keep up—not necessarily broken footing drains. Start by directing meltwater away from the foundation, checking exterior grates and downspouts, and testing the sump pump under a simulated melt. If backups continue after the thaw or you see new foundation seepage, call a professional.
Why This Happens
Rapid snowmelt sends a lot of water into a small area. If the ground is still frozen, water can’t soak in and instead runs along the surface toward the foundation. Downspouts, drain grates, and drain pipes can be buried or blocked by snow and debris, so the water has nowhere to go but into basement drains. A failing or overwhelmed sump pump will make the problem visible inside. While damaged footing drains or drainage tile are possible, most thaw backups are caused by temporary surface drainage issues.
Step-by-Step What to Do
Clear meltwater channels away from the foundation and downspout discharge
- Shovel or melt narrow channels that guide water away from the foundation and toward a yard low spot or street drain. Keep channels shallow so they don’t undermine soil against the foundation.
- Move piled snow away from the house and roofline so meltwater doesn’t run back toward the foundation.
Inspect exterior drain grates and downspout extensions for blockages buried by snow
- Look for and uncover any drain grates, catch basins, and downspout extensions that may be hidden under snow or ice. Clear away debris so water can enter the drains.
- Use a broom or long-handled tool to probe cautiously if the surface is icy—don’t stand on unstable ice near the foundation.
Test sump pump under a simulated melt by running a hose at gutter level
- Run a garden hose at or just below gutter/downspout height to mimic heavy melt. Watch the sump pump cycle, listen for unusual noises, and confirm it discharges away from the house.
- If the pump doesn’t run, the float is stuck, or it runs but water still backs up, there may be a clog in the discharge, a bad check valve, or the pump is undersized or failing.
Look for soggy spots in yard that indicate saturated ground near the house
- Walk the perimeter and note any saturated or soggy areas close to the foundation. These indicate the ground is holding water and may be overpowering the footing drains.
- Check basement walls and the area where the footing drain exits for fresh dampness or new staining that suggests seepage.
If you want more on how drains behave during a thaw, see Drain floods after thaw or read about similar neighborhood events like Backup after heavy snowfall melts.
What Not to Do
- Don’t pile roof or driveway snow against or above the grade near the foundation—this directs meltwater toward the house.
- Don’t ignore repeated thaw-time backups; repeated events can indicate a failing sump pump, blocked footing drains, or a larger grading issue.
- Don’t try to fix large foundation seepage or complex drain tile problems yourself—call a professional if the issue persists or you see new seepage.
When to Call a Professional
Call a pro when backups continue after the thaw and temporary fixes, when water appears through foundation cracks or new seepage points, when multiple drains back up at once, or when your sump pump fails during a test. A contractor can inspect footing drains/drain tile, test discharge lines, and recommend repairs or regrading if surface drainage is inadequate.
Safety Notes
- Avoid standing in basement water near electrical outlets, panels, or appliances. If water reaches electrical equipment, shut power to the area at the main breaker before entering and only if you can do so safely.
- Use caution with hoses and tools on icy surfaces; slip-and-fall risk is high during thaw. Wear boots with good traction.
- Don’t dig deeper than needed close to the foundation—excessive excavation can undermine footings. For major work, hire someone experienced.
Common Homeowner Questions
- Will a temporary channel fix prevent future backups? It helps immediately but won’t solve underlying issues like poor grading or a failing pump.
- Can I run water tests on the sump pump myself? Yes—running a hose to simulate melt is a safe, common test if you avoid electrical hazards.
- Is a clogged downspout likely the cause? Often yes—buried downspout extensions and blocked grates are common and simple to clear.
More in this topic
For more related fixes and similar symptoms, see Basement Drain Backs Up Only After Rain.