Abstract: A pipe swivel joint for use at underwater or other submerged locations provides a system for circulating a lubricant under pressure through the joint's bearing race chamber and for monitoring the lubricant pressure to detect any leaks in the joint. The composition of the circulating lubricant can be analyzed to ascertain when an outward leak of pipe fluid or an inward leak of sea water into the lubricant exists. The leak can be halted by changing the lubricant pressure to match the pressure of the pipe fluid or the pressure of the sea water leaking through a defective seal so that operations can continue until the leak is repaired.