I have a double pole X10 switch used for a pool waterfall and a single pole X10 switch used for the pool light. They turn themselves on at will. Any ideas on how to repair or resolve the issue.

Have you tried setting the addresses for the switches to something different? It may be that someone else nearby is using X10 devices that may have the same addresses as your switches.

When you change the addresses, try a different house code as well.