Symptoms
- Drip or seepage specifically at a threaded connection
- Leak may be worse under pressure or heat (hot water lines)
- Visible old tape peeking out from the joint
- Connection may feel slightly loose
Likely causes
- CommonTeflon tape wrapped in the wrong directionTape must be wrapped clockwise (as viewed from the pipe end) to stay in place as the fitting is threaded on; the wrong direction can unwind it during assembly.
- CommonInsufficient tape or sealant appliedToo few wraps, or skipping pipe joint compound where needed, leaves gaps in the seal.
- PossibleFitting not tightened enoughEven with good tape, an under-tightened fitting won't compress the tape enough to seal fully.
- Less commonDamaged or cross-threaded fittingIf the threads themselves are damaged, no amount of tape will create a reliable seal.
What to do
- Shut off water to the affected line before disassembling the joint.
- Unscrew the fitting fully and remove all old tape or sealant residue from both threaded surfaces.
- Inspect the threads for damage, cross-threading, or excessive wear.
- Wrap new Teflon tape clockwise (as viewed looking at the pipe end) around the male threads, using 3–4 wraps for a good seal.
- For added security on water lines, consider applying pipe joint compound (pipe dope) over the tape as well, if compatible with your pipe material.
- Thread the fitting back on by hand first to avoid cross-threading, then tighten with a wrench until snug, typically 1–2 full turns past hand-tight.
- Turn water back on slowly and inspect the joint closely for any remaining seepage.
Tools and parts
- Wrench
- Teflon tape
- Pipe joint compound (optional)
Teflon thread seal tapeSearch: “plumbers Teflon tape”
When to call a pro
Call a plumber if the threads themselves appear damaged, since a new fitting may be needed rather than just retaping.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.