Teflon Tape: What It Is, Types, and How to Use It

What is Teflon tape?

Teflon tape, more accurately called PTFE (polytetrafluoroethylene) thread seal tape, is a thin, slick film wound onto a small spool. You stretch and wrap it around male pipe threads before assembly. The tape fills tiny gaps between tapered threads and reduces friction, so fittings seat smoothly and seal against leaks. Despite the common name, the tape is not sticky; it clings because it’s soft and slightly stretches into the thread profile.

PTFE is chemically inert, hydrophobic (repels water), and withstands a wide temperature range, which makes the tape useful for many household and light commercial connections. Typical applications include water plumbing, compressed air, and—when using the correct grade—fuel gas and oxygen service.

Common uses and where you’ll see it

You’ll use Teflon tape on tapered pipe threads, such as NPT (National Pipe Taper) or BSPT. Examples:

Shower arms and shower heads (NPT threads)
Water heater nipples and dielectric unions
Hose bibbs and boiler drain valves
Iron pipe to brass adapters for faucets or filters
Compressed air quick-connect manifolds
Fuel gas black-iron or brass threaded joints (with gas-rated tape)

Where you won’t use it:

Compression fittings (olive/ferrule) and flare fittings: these seal on a metal-to-metal or gasket face, not the threads.
Flexible faucet or toilet supply lines with rubber washers: the washer seals; tape only gets in the way.
Slip or solvent-welded PVC joints: use primer and cement instead.

Types, colors, and ratings

PTFE tapes come in different densities, thicknesses, widths, and color codes. While some colors vary by brand, these are widely recognized in North America:

White: general-purpose, low-density PTFE for water and air. Common for household plumbing. Often 3–4 mil thick.
Pink: heavy-duty PTFE for water lines; thicker and denser than white for a more robust seal on larger or rougher threads.
Yellow: gas-rated PTFE for natural gas, propane, and butane. Denser, often double-thick. Look for approvals like UL/CSA.
Green: oxygen-clean PTFE for oxygen lines; oil-free. Only for oxygen service; don’t substitute other tapes.
Gray (often with nickel): PTFE with nickel additive for stainless steel to prevent galling and seizing.

You’ll also see premium, extra-thick blue tapes marketed for potable water or general sealing. Always check the label for application and approvals, as color alone isn’t a guarantee across all brands.

Common widths: 1/2 inch for 1/2–3/4 inch pipe, 3/4 inch or 1 inch for larger fittings. Thicker, higher-density tapes need fewer wraps and are less likely to shred.

How to choose the right tape

Match the service: white or pink for water, yellow for fuel gas, green for oxygen. Use gray/nickel on stainless to avoid galling.
Check approvals: for gas, look for UL/CSA marks and local code acceptance. Some jurisdictions prefer paste sealant or allow both.
Pick the right width: 1/2 inch covers most household needs; wider tape is easier on bigger fittings.
Consider thickness and density: thicker tape fills gaps faster and is easier for beginners to apply neatly.

How to apply Teflon tape (step-by-step)

Clean the threads. Remove old tape, paste, dirt, and corrosion with a wire brush or rag.
Start on the second thread. Set the tape on the male threads one thread back from the end to reduce stray shreds entering the system.
Wrap in the tightening direction. Looking straight at the pipe end, wrap clockwise for right-hand threads (the vast majority). This way, tightening won’t unwind the tape.
Overlap by about half the tape width. Keep steady tension so the tape molds into the threads without tearing.
Use the right number of wraps. For standard white tape, 4–6 wraps on 1/2 inch fittings is typical. For thicker tape, 2–4 wraps may be enough. Threads should look evenly covered but still defined.
Smooth and assemble. Press the tape into the threads with your fingers, then hand-tighten the fitting before using a wrench. Avoid backing off after tightening; if you must reposition, remove and re-tape.

Pro tip: Many pros use a belt-and-suspenders approach—two to three wraps of PTFE tape plus a light coat of compatible thread sealant paste ("pipe dope") over the tape. This can reduce weeping on stubborn joints. Verify compatibility with gas or plastic components as required.

Common mistakes to avoid

Wrapping backward. If the tape unravels as you tighten, you wrapped in the wrong direction.
Starting at the first thread. Shreds can get into aerators, valves, or gas orifices. Start on the second thread.
Too little or too much tape. Too little can leak; too much can split plastic fittings or distort metal connections. Aim for neat coverage with threads still visible.
Using tape on compression, flare, or gasketed connections. It doesn’t help and can cause leaks or debris issues.
Wrong tape for the job. Don’t use white tape on gas or oxygen service. Follow color/application ratings and code.
Overtightening plastic threads. PTFE reduces friction, making it easy to crack female PVC or CPVC. Snug plus a quarter-turn is often enough; check manufacturer guidance.

Practical examples

Installing a shower arm: Wrap the male threads of the shower arm with 4–5 wraps of white or pink tape, clockwise. Thread into the wall elbow, tighten, and attach the showerhead (also taped if it uses NPT threads). No tape needed on a shower hose that seals with a washer.
Replacing a water heater: Use 3–4 wraps of pink tape on the heater nipples, then consider a thin layer of compatible paste over the tape before attaching dielectric unions. Check for leaks after filling and heating.
Hooking up a gas appliance: If permitted locally, apply 2–3 wraps of yellow gas-rated tape on male threads, then assemble the black-iron or brass fittings. Many pros and codes prefer or require gas-rated paste, with or without gas-rated tape. Always leak-test with a gas leak solution and follow code.
Assembling an air compressor manifold: Use 3–4 wraps of white or blue heavy tape on all NPT threads; avoid tape on quick-connect couplers that seal on internal gaskets.

Related terms

PTFE (polytetrafluoroethylene): The material used for the tape.
Thread sealant paste (pipe dope): A brushable compound used alone or with tape to seal threads.
NPT/BSPT: Common tapered thread standards that rely on thread interference to seal.
Compression/flare fittings: Connection types that seal on faces or ferrules, not with thread seal tape.
O-ring/gasket: Elastomer seals found in many connectors that do not require tape.

Care and storage

Keep the tape roll clean, dry, and protected from crushing. PTFE itself is stable and long-lasting, but a deformed or dirty roll is hard to use neatly. Store by application (water, gas, oxygen) to avoid cross-contamination—especially for oxygen-rated tape.

With the right type and a tidy wrap, Teflon tape is a quick way to stop weeping threads, make assembly smoother, and help fittings come apart cleanly in the future.