Pipe sizes are not what they sound like — the name is a nominal size, not the actual measurement. Knowing how to measure the diameter saves a trip back to the store with the wrong fitting.
The nominal size
A half-inch pipe is not half an inch across; the name refers to the pipe's nominal size, and the actual outside diameter is larger.
The measure
Measure the outside diameter with calipers or a tape, then match it to a pipe-size chart for the material.
The thread
Threaded fittings are measured by their nominal size, and the threads must match the pipe exactly.
The tip
For a quick match, take the old part to the store rather than trusting a guess. freezing winters put stress on exposed lines, and many older rowhomes have aging supply lines In Washington, a pro always matches the exact size.
The chart
Measure the outside diameter and match it to a chart for the material, because copper, PEX, and PVC all size differently. The nominal size is not the measured size.
The call
Get the size right before you cut. Call 888-217-3585 and Washington Plumbing Experts will match you with a Washington pro.
Plumbing in Washington: what to know
In Washington, freezing winters put stress on exposed lines, and many older rowhomes have aging supply lines. Pros in our network know the local quirks and bring the right parts on the first visit.
Across District of Columbia County — from Mount Rainier, Hyattsville and Takoma Park to ZIP codes like 20001, 20535, 20005 — homeowners deal with the same kinds of issues. The tips above apply locally, and when a job goes beyond a quick fix, a vetted local pro is only a call away.
Need a hand in Washington?
If a plumbing issue is beyond a quick fix, don't wait for it to get worse. Call 888-217-3585 and Washington Plumbing Experts will match you with a vetted local pro — usually within minutes. Learn more about plumbing help in Washington.