If your sink smells like sewer, it's likely due to a problem with the drain or the plumbing. Here are some steps to troubleshoot and fix the issue:

1. Check the P-trap: The P-trap is a U-shaped pipe underneath your sink that traps water and prevents sewer gas from coming back up the drain. Check to make sure the P-trap is not clogged with debris, such as hair or soap scum. If it is, clean it out and see if that resolves the issue.

2. Run hot water: Sometimes, running hot water for a few minutes can help clear out any buildup in the drain that may be causing the odor.

3. Use baking soda and vinegar: If the smell persists, you can try using a mixture of baking soda and vinegar to clean the drain. Pour about 1/2 cup of baking soda down the drain, followed by 1/2 cup of vinegar. Let the mixture sit for a few minutes, then flush the drain with hot water.

4. Check for leaks: If the smell persists after trying the above steps, there may be a leak in the drain or plumbing that is causing the odor. Check under the sink for any signs of leaks or water damage.

5. Call a plumber: If you're unable to identify or fix the problem on your own, it's best to call a licensed plumber to diagnose and repair the issue. They may need to replace a damaged pipe or use specialized tools to clear out a blockage in the drain.

By following these steps, you should be able to troubleshoot and fix the issue of your sink smelling like sewer. If the issue persists, don't hesitate to contact us for further assistance.