Installing PEX piping under a sink is a cost-effective and DIY-friendly way
to upgrade your plumbing. PEX is flexible, durable, and resistant to corrosion,
making it a popular alternative to copper or PVC pipes. In this guide, we’ll
walk you through the process of installing PEX pipes under your sink while
optimizing for SEO-friendly keywords like "how to install PEX pipe," "PEX
plumbing under sink," and "DIY PEX installation."
Why Choose PEX Pipes?
Before diving into the installation steps, let’s address why PEX is ideal
for under-sink plumbing:
Flexibility: Easily navigates tight spaces without elbow fittings.
Freeze Resistance: Expands slightly to prevent bursting in cold
weather.
Quick Installation: Requires fewer tools than copper.
Cost-Effective: Cheaper than copper and easier to repair.
Tools and Materials Needed
To install PEX pipes under your sink, gather these essentials:
PEX tubing (1/2-inch diameter is standard for sinks)
PEX cutter or sharp utility knife
Crimp rings or clamp rings (depending on connection type)
Crimping tool or clamp tool
Shutoff valves (angled or straight)
Pipe brackets or straps for securing
Teflon tape (for threaded connections)
Adjustable wrench
Step 1: Turn Off the Water Supply
Locate the main water shutoff valve for your home and turn it off.
Open the sink faucet to drain any remaining water in the pipes.
Step 2: Remove Old Pipes (If Applicable)
If replacing existing plumbing:
Use a wrench to disconnect old supply lines from the shutoff valves.
Remove corroded or damaged pipes carefully to avoid harming nearby
fixtures.
Step 3: Measure and Cut PEX Tubing
Measure the distance between the shutoff valve and the sink faucet.
Use a PEX cutter to make clean, straight cuts (avoid jagged edges).
Leave a little extra length for adjustments.
Pro Tip: Label pipes with tape (hot vs. cold) to avoid confusion later.
Step 4: Attach PEX to Shutoff Valves
Slide a crimp ring onto the PEX tubing.
Insert the PEX fitting (included with shutoff valves) into the tube
end.
Position the crimp ring 1/8-inch from the tube’s end and use the crimping
tool to secure it.
Connect the fitting to the shutoff valve and tighten with a wrench.
Step 5: Route PEX to the Faucet
Secure the PEX tubing along the wall or cabinet using pipe brackets to
prevent sagging.
Avoid sharp bends; use 90-degree elbow fittings if necessary.
Step 6: Connect PEX to the Faucet
Attach the PEX tubing to the faucet’s hot and cold supply lines using the
same crimp method.
Wrap Teflon tape around threaded connections for a watertight seal.
Step 7: Test for Leaks
Slowly turn the main water supply back on.
Check all connections for leaks. Tighten fittings or re-crimp if
needed.
Run the faucet to flush out debris.
Common Mistakes to Avoid
Overtightening Fittings: This can crack the PEX.
Poor Support: Unsecured pipes may vibrate or leak.
Using Wrong Tools: Always use a PEX-specific cutter and crimper.
FAQs About Installing PEX Under Sink
Q: Can I connect PEX directly to a copper pipe?
A: Yes! Use a PEX-to-copper transition fitting and follow the same crimping
steps.
Q: How long does PEX last?
A: Properly installed PEX can last 40-50 years.
