Quick Answer:
If you run the kitchen faucet after a long trip and the sink overflows quickly, first stop the water and don’t keep pouring. In most cases the trap will refill after running a short stream of water (about 30–60 seconds). If water keeps backing up or the sink stays full, treat it as a clog rather than just a dried trap and take cautious steps to test and clear the line or call a plumber.
Why This Happens
When a home sits unused, the water in the P-trap can evaporate a bit and the line can settle. That can let odors out, but it can also reveal an existing partial blockage or allow settled debris to shift. Running the faucet aggressively can push that debris into a spot that causes a quick backup. Stagnant water alone usually won’t cause a sudden overflow unless there’s a partial clog waiting behind it.
If your building recently had pressure changes, city work, or outages, that can move solids and sludge in the sewer or shared line and lead to similar symptoms. If you want to read about related situations, consider the article on Overflow after city outage and the one on Sink overflows only at night.
Step-by-Step What to Do
1) Stop the water immediately
- If the sink is overflowing, turn off the faucet at once to avoid adding more water to the line.
2) Refill the trap gently
- Run a steady, moderate stream of water into the sink for 30–60 seconds to refill the P-trap. This replaces evaporated water and restores the seal against sewer gas. Do not run a full blast.
3) Watch for how the sink behaves
- If the overflow starts again quickly when you refill, stop and look for signs of slow draining: water level staying high, gurgling in other fixtures, or water backing into nearby drains.
4) Do a single full-sink dump only if water is dropping
- If the water level is slowly dropping (not staying full) you may try one deliberate full-sink flush: fill the basin to a few inches and release it quickly to push water down the drain. Do this only once — a single strong flush can sometimes move a soft blockage forward.
- If the water does not drop or the sink stays full after that flush, stop. At that point treat the situation as a clog rather than a dry trap.
5) Basic checks and simple clearing
- Remove visible debris from the stopper or strainer. Use a plunger over the drain (cover overflow if present) with a few firm pumps.
- If you remove the P-trap to inspect, have a bucket and wear gloves. Only remove it if you’re comfortable; otherwise skip to calling a pro.
What Not to Do
- Don’t ignore a vacation-return overflow as “just stale water.” It can reveal a partial clog that will come back.
- Don’t keep running water if the sink overflows quickly; that only spreads sewage and risks more damage.
- Don’t repeatedly perform forceful flushes or pour chemicals down the drain when the sink stays full — these can make the problem worse or damage pipes.
- If backups are immediate and repeated, don’t try to handle complex sewer issues yourself; a plumber is appropriate.
When to Call a Professional
- Call a plumber if the sink remains full after the single flush or if plunging and visible cleaning don’t restore flow.
- Call immediately if multiple fixtures back up at once, water is coming from floor drains, or there is sewage on floors — these are signs of a larger sewer or municipal line problem.
- If you’re not comfortable removing traps or snares, or if the clog is deep and recurring, a professional inspection and possible camera survey will find the cause.
Safety Notes
- Turn off the water and avoid standing in flooded areas. Sewage-contaminated water is a health hazard.
- Wear gloves and eye protection if you handle trap removal or scooping water.
- Use mechanical methods (plunger, hand auger) before chemical cleaners. Many drain chemicals are hazardous and can damage pipes or react if mixed with other substances.
- If you suspect sewer gas or strong odors, ventilate the area and do not use open flames; call a professional if the odor is strong or persistent.
Common Homeowner Questions
- Why did this happen only after my trip? Evaporation and shifted debris can reveal a partial clog that only becomes noticed when you run water after a long idle period.
- Can I just pour bleach or drain cleaner? No. Don’t use chemical cleaners in a full sink or with repeated overflows; they can be dangerous and may damage pipes.
- When is a plumber necessary? If the sink stays full after the one flush, if multiple drains back up, or if you’re unsure about removing parts, call a plumber.