Quick Answer:
If your drains seem slower and clogs are harder to clear in winter, colder temperatures are often part of the problem. Soap, oils and fats firm up at lower temperatures and move more slowly through pipes, so buildup and blockages can develop or feel worse. Check how fast water drains at different temperatures and follow the steps below to test and improve flow safely.
Why This Happens
Three simple factors explain winter clogs:
- Temperature lowers the fluidity of soaps, fats and grease, so they stick to pipe walls more easily.
- Colder water drains more slowly, which gives solids and soap scum more time to accumulate instead of flushing away—note the direct correlation between temperature and drainage speed when you test your drains.
- Household habits can change seasonally (hot showers, more indoor activity), increasing soap and hair in drains at the same time pipes are colder.
If you suspect soap is a main contributor, see the note on cleaned buildup and products like enzyme cleaners below and consider reading about Soap buildup from hard water for more background on how minerals worsen the problem.
Step-by-Step What to Do
1. Observe and record
- Run a known amount of water (for example, from a full sink or a fixed-duration shower) and time how long it takes to drain at typical house temperature.
- Repeat with hotter tap water. If the drain clears noticeably faster with warmer water, temperature is influencing drainage speed.
2. Remove visible debris
- Use a drain cover to catch hair and solids. Remove hair and gunk from visible drains by hand with gloves or a small tool.
- For shower or tub clogs that followed recent maintenance, check for issues like trapped strands or materials—consult guidance on problems such as Hair clog after plumbing repair if you suspect repair work introduced debris.
3. Clear the P‑trap and clean the trap arm
- Under sinks, place a bucket under the P-trap, loosen slip nuts and remove the trap to clear trapped hair, soap and debris. Reassemble carefully, checking for leaks.
- If you’re not comfortable under the sink, skip to the professional step below.
4. Use safe cleaning methods
- Try flushing the drain with hot (not boiling) water to soften soap and fats—boiling water can damage some plastic pipes.
- Consider enzyme-based drain cleaners designed to break down organic buildup; follow label directions.
- A manual plumbing snake can dislodge blockages farther down the line when used correctly.
5. Preventive adjustments for winter
- Run warmer water periodically to help keep fats and soap moving during cold snaps.
- Use drain strainers and clean them frequently.
- Reduce heavy oily disposal down kitchen sinks and wipe greasy pans with a paper towel before rinsing.
What Not to Do
- Do not ignore seasonal temperature effects. Treat winter clogs as influenced by colder temperatures rather than assuming nothing has changed.
- Avoid mixing chemical drain cleaners or pouring strong acids into drains—these can damage pipes and create dangerous fumes.
- Do not force a snake or tool without knowing what’s down the drain; you can worsen a blockage or damage a fixture.
When to Call a Professional
- Multiple slow drains or backups in several fixtures at once—this can indicate a deeper sewer or mainline problem.
- Persistent clogs that return after reasonable DIY steps (clearing trap, snaking, hot water) or when you smell sewage.
- If you’re uncomfortable disassembling traps or using a snake, or if drain lines are hard to access safely.
Safety Notes
- Wear gloves and eye protection when working on drains. Place a bucket to catch water from traps.
- Do not pour boiling water into PVC or plastic drains—use very hot tap water instead unless you know your pipe material tolerates boiling water.
- Never mix chemical cleaners; follow product warnings and keep products out of reach of children and pets.
Common Homeowner Questions
- Will warmer water always clear a winter clog? — Warm water can soften soaps and fats and often improves flow, but it won’t remove solid obstructions or mineral scale.
- Are enzyme cleaners safe for pipes? — Yes, enzyme and bacterial cleaners are generally safe and work slowly to break down organic buildup; follow product instructions.
- Does hard water make winter clogs worse? — Hard water can combine with soap to form harder scum, which is why mineral-related buildup is often part of the issue.