The answer to 'why is my sump pump burst pipe' is that a burst pipe in your sump pump system is often caused by freezing temperatures, excessive water pressure, or a mechanical failure in the pump itself. The symptoms may include water leaking around the sump pump, a sump pump that won't turn on, or water backing up in your basement or crawl space.
To fix a burst sump pump pipe, you'll need to first shut off power to the pump, drain the water, and then replace the damaged section of pipe. This may require digging around the sump pit, cutting out the broken pipe, and splicing in a new section. If you're not comfortable with plumbing repairs, it's best to call a professional plumber who can properly diagnose and fix the issue.