The answer to 'sump pump won't flush' is that there are several common causes, including a clogged discharge line, a faulty sump pump, or a power failure. Symptoms may include the sump pump running continuously without draining the water, or the pump not turning on at all.
Some potential solutions include clearing any debris or blockages in the discharge line, checking the sump pump for issues like a stuck float switch or worn impeller, and ensuring the pump is getting power. However, if the problem persists or you're not comfortable troubleshooting it yourself, it's best to call a professional plumber who can properly diagnose and fix the issue.