You should turn the hot and cold water supplies on. Check for kitchen tap leaks. If the problem is not fixed after this step, call a plumber. Plumbing projects often turn out to be quite complex and you may need to use tools that are beyond your skills. If you're unsure of your plumbing skills, don't attempt this project until you have adequate time and money. After all, you might not be able to fix it yourself, so hiring a plumber is probably the best option.