Winter Drain Maintenance: Protecting Your Pipes When Temperatures Drop

Upstate South Carolina winters are mild compared to the Northeast, but we get enough freezing nights to cause real problems. The January 2025 cold snap that pushed temperatures into the single digits across Spartanburg and Cherokee counties generated more frozen pipe calls in one week than we normally see in an entire winter. Homes in Chesnee, Campobello, and Landrum — the higher-elevation communities in our northern service area — were hit hardest. Crawlspace pipes that had survived 15 mild winters finally met a cold snap they couldn’t handle.

Here’s how to stay ahead of it.

Drain-Specific Winter Risks

Frozen Exterior Drain Lines

Drain lines that run through uninsulated crawlspaces, exterior walls, or near the foundation are vulnerable during prolonged freezes. Unlike supply lines (which can burst from ice pressure), drain lines freeze and block – creating backups inside the home.

Common locations: laundry drains routed through exterior walls, kitchen drains in island configurations with crawlspace exposure, and basement floor drains near foundation walls.

Grease Solidification

Grease that’s been slowly building up inside kitchen drain lines all year solidifies faster in cold weather. A drain that was “slow but working” in October can become completely blocked in January when the combination of grease buildup and cold temperatures creates a solid plug.

Root Dormancy Myth

Many homeowners assume tree roots are dormant in winter and won’t affect drains. While root growth slows, existing root intrusion continues to catch debris year-round. Winter is actually when root-compromised sewer lines are most likely to backup – holiday cooking pushes more grease and food waste through already-restricted lines.

Winter Drain Maintenance Checklist

Before the First Freeze

1. Clear slow drains now. Don’t enter winter with a drain that’s already struggling. A professional drain cleaning before December is the best preventive measure.

2. Insulate exposed drain pipes. Pipe insulation (foam sleeves) on exposed drain lines in crawlspaces and unheated areas. Focus on horizontal runs that can hold standing water.

3. Check cleanout caps. Missing or broken cleanout caps allow cold air directly into the drain system. Replace any damaged caps before freezing temperatures arrive.

4. Clear gutters and downspouts. Clogged gutters can cause ice dams that direct water toward the foundation, potentially freezing and blocking exterior drain lines.

During Cold Snaps (Below 25°F)

1. Keep cabinet doors open under kitchen and bathroom sinks on exterior walls. This allows heated room air to reach the pipes.

2. Let faucets drip. A slight drip from faucets served by pipes in exterior walls keeps water moving and prevents freezing. Even a trickle is enough.

3. Maintain heat. Don’t drop the thermostat below 55°F, even if you’re away. The cost of heating is far less than the cost of frozen pipe repairs.

4. Run water periodically in infrequently used fixtures (guest bathrooms, basement sinks). P-traps can dry out or freeze.

If a Drain Freezes

1. Do not pour boiling water down the drain. Thermal shock can crack PVC pipes and porcelain fixtures.

2. Try warm (not hot) water – run warm water continuously to slowly thaw the blockage.

3. Apply gentle heat to exposed sections of the frozen pipe using a hair dryer or heat lamp. Never use a torch or open flame.

4. Call a plumber if you can’t locate the frozen section or if the freeze is inside a wall. We use specialized thawing equipment that’s safe for all pipe materials.

Post-Winter Inspection

After the last freeze of the season:

• Check all visible pipes for new leaks or damage
• Test outdoor hose bibs for flow and leaks (frost damage may not be apparent until thaw)
• Run all fixtures that weren’t used regularly during winter
• Schedule a drain camera inspection if you experienced any backups during the season

YOUTUBE EMBED: One Drain – Waldrop Plumbing Air Electric TV Commercial — @YallCallWally

Call Waldrop Plumbing Air Electric at (864) 536-0887 for winter drain service or freeze damage repair.

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