The answer to 'what causes sink' is a variety of issues, including clogged drains, worn-out seals, and problems with the sink's plumbing. Clogged drains are one of the most common causes of sink issues, as hair, food particles, and other debris can build up over time and restrict water flow. Worn-out seals around the sink can also cause leaks and water damage. Additionally, issues with the sink's plumbing, such as a broken pipe or a faulty faucet, can lead to problems with the sink.
If you're experiencing issues with your sink, it's important to identify the underlying cause and address it promptly to prevent further damage to your home. In some cases, you may be able to fix the problem yourself, but for more complex issues, it's best to call a professional plumber who can diagnose and repair the problem correctly.