Far more common than you might think.   Washing machine related failures are the leading cause of home water damage losses.  Most washing machines come with a black rubber hose from the manufacturer.  These rubber hoses should be replaced after 3 years.  If your hose is older than that your home is at risk.  Replacement hoses with steel or nylon braiding are rated to last longer, but nothing lasts forever.

The washing machine itself lets hot and cold water in as it needs it, but the water is always on and the hose is under pressure at all times.  Eventually it will fail.  Murphy’s Law indicates that it will likely fail when you are not at home, increasing the resultant damage.  When traveling it’s a good idea to shut off the water supply behind the washer as an extra precaution.