Quick Answer:
If your kitchen sink is slow after returning from a long trip, start by flushing the drain thoroughly after vacation. Run hot water for several minutes, use a bit of dish soap to break up hardened grease, and then check the strainer and P-trap. If the slow flow continues after those basic steps, move on to a manual clean or call a plumber.
Why This Happens
When a sink sits unused, grease, soap scum and food particles can cool and harden inside the pipe. With no regular hot water to carry them away, the buildup narrows the flow and makes the drain sluggish. You might see the symptom described as Slow drain with no visible clog when the pipe looks clear at the top but is restricted further down.
Step-by-Step What to Do
1. Flush the drain thoroughly after vacation
- Run the hottest tap water you have for 3–5 minutes to reheat and loosen any grease hardened in the line.
- While the hot water is running, add a tablespoon of liquid dish soap to help dissolve fatty residues.
2. Run a controlled flush
- After the initial hot-soap rinse, run hot water for another 2–3 minutes at full flow. This helps move loosened material farther down the system where the municipal line or main stack can handle it.
3. Check and clear the strainer and visible trap
- Remove the sink strainer or basket and clear any trapped debris.
- If comfortable, place a bucket under the P-trap, loosen the slip nuts, and remove the trap to clear out gunk. Reassemble carefully and test the flow.
4. Use a plunger or hand auger if needed
- Try a sink plunger first: seal the overflow (if present) and plunge firmly for a minute.
- If plunging fails, use a hand-held drain snake focused through the strainer opening to break up or retrieve the clog. Avoid forcing a powered auger unless you know how—it can damage fittings.
5. Final flush and test
- Once the trap or snake work is done, run a long, hot-water flush again (3–5 minutes) to ensure remaining grease moves through the system.
- Check for improvement by running and filling the sink a few times. If flow is restored, follow prevention steps below.
6. Prevent recurrence
- Wipe pans and throw solid grease in the trash instead of down the drain.
- Occasional hot-soap flushes after cooking and regular trap checks help prevent hardened buildup. If the problem keeps returning, consider enzyme-based maintenance treatments per product instructions, or consult a pro.
Grease buildup returns after cleaning is a common complaint that usually means behavior or an upstream issue needs addressing.
What Not to Do
- Do not resume heavy use without flushing. Let the initial hot-soap flush and any mechanical cleaning work first.
- Do not pour concentrated chemical drain cleaners down the sink to try to dissolve hardened grease. They can damage pipes, fittings, and your skin if misused.
- Avoid using boiling water on older PVC pipes—use very hot tap water instead to be safe.
When to Call a Professional
- Call a plumber if the sink stays slow after you’ve flushed, cleaned the strainer and P-trap, and tried a hand snake.
- Contact a pro if you smell sewage, notice leaks when you remove the trap, or if multiple drains in the house are slow—these can indicate a blockage or venting problem deeper in the system.
- If you’re uncomfortable disconnecting plumbing or using a snake, a plumber can safely inspect and clear the line.
Safety Notes
- Wear gloves and eye protection when handling greasy debris or working under the sink.
- Turn off water supply valves if you disconnect plumbing, and keep a bucket and rags handy to catch spills.
- Never mix chemical cleaners. If any were used previously, warn the plumber—some mixtures can be hazardous.
Common Homeowner Questions
- Q: How long should I run hot water to flush the line?
A: Aim for 3–5 minutes for each flush to reheat and move hardened grease. - Q: Will dish soap and hot water damage pipes?
A: No. Small amounts of dish soap with hot water are safe and effective at loosening grease. - Q: Can I prevent this from happening after future trips?
A: Yes. Before leaving, flush hot water and add a small amount of dish soap, and avoid pouring grease down the sink.