Many people may doubt that why using IP67 buried light in project, sometimes there would still be leaking, even international brands with IP67 test report
So why the IP67 buried lights still leak? 

To know the leaking reason, firstly you need figure out what’s IP67 mean. IPX7 indicates that putting equipment into water of specified pressure, after specified time, the water leak into shell does not reach harmful level.

The reason why buried lights still leaking? It could be summarized as following 4 reasons:
① unreasonable design② defective material③ defective process④ wrong installation