MIP

MIP stands for Male Iron Pipe and refers to a fitting or pipe end with external threads cut to the NPT standard. The threads are tapered, which means they get slightly smaller in diameter as they extend outward, creating a wedging action that helps seal the joint when screwed into a female-threaded fitting (FIP).

In the field, you'll encounter MIP on galvanized steel, brass, and PVC adapters, elbows, tees, and nipples. It's one of the two standard threaded connection types in residential and light commercial work. The tapered thread design means you don't need a washer or rubber seal to make a tight joint—the seal comes from thread-locking compound and the mechanical fit of the threads themselves. That said, most plumbers still wrap the male threads with PTFE tape or pipe dope for a more reliable seal.

MIP matters because it's the foundation of threaded plumbing work. You'll be screwing male threads into female fittings constantly—on water heater connections, shutoff valves, hose bibbs, and countless rough-in situations. Knowing how to cut, thread, and seal MIP connections properly keeps leaks out of the wall and out of your callback list.