Jeff, I assume it's city water. I'll find that out today too.
Thanks for your answers. I'll keep you posted.
1. Is the house on city sewer or septic system?
2. Does the house have city water or a well?
3. What do you mean by sinkhole?
4. Why is a washer outside and not connected to a drain?
The type of soils in you area don't actually create sinkholes, but there is obviously something going on to create a depression. Has the septic system top collapsed? Is there some type of underground tank that is collapsing? Does an underground drainage pipe have a crack that is allowing soil/sand to infiltrate and be carried downstream, creating a depression?
I would be most concerned if the house uses a well for water. It is possible the well could be impacted by the discharge from the washer, creating a major problem.