Most modern fridges have ice makers and water dispensers requiring a cold water supply line. Standard practice: 1/4 inch copper or PEX line from the cold water supply (under sink) to the fridge, with a small saddle valve or T-fitting to tap into the cold supply. The work involves cutting into existing plumbing, running the new line, and connecting at the fridge.
This guide covers running a fridge water line from the kitchen sink's cold supply to a fridge in standard placement.
Before you start
Three things to settle:
1. Saddle valve vs T-fitting. Saddle valve: clamps onto existing pipe with a piercing needle to create the tap. Easy install, but unreliable long-term — leaks common. T-fitting (proper plumbing): cut existing supply line, install T-fitting with shut-off, run new line. Reliable, recommended over saddle valves.
2. Copper, PEX, or plastic tubing. 1/4 inch copper: traditional, rigid, requires bending tools. 1/4 inch PEX: flexible, easier to route. Clear plastic tubing: cheap but degrades over time. PEX is the modern choice for fridge water lines.
3. Plan the route to fridge. Most direct route: through cabinets, behind base cabinets, up to fridge. Verify path is unobstructed. Pre-plan drilling holes through cabinet sides for line.
What you'll need
Tools
- Pipe cutter (for copper)
- PEX cutter or sharp utility knife (for PEX)
- Adjustable wrench
- Drill with bits
- Bucket
Materials
- 1/4 inch PEX or copper tubing
- T-fitting (1/2 inch × 1/2 inch × 1/4 inch reducing tee)
- Mini shut-off valve (1/4 turn ball valve, 1/4 inch)
- Compression fittings (matched to tubing)
- PEX crimp rings or compression nuts
- Plumber's tape
- Drip pan (under fridge connection — optional but smart)
Skip saddle valves; install proper T-fitting
Saddle valves leak — usually slowly, sometimes catastrophically. Bad reputation in plumbing world for good reason.
T-fitting requires more work (cut and re-connect existing supply) but is permanent and reliable.
Use saddle valve only as temporary; replace with T-fitting at first opportunity.
Step-by-step instructions
Plan and shut off water
Identify cold water supply under kitchen sink.
Plan tubing route from sink to fridge.
Shut off cold water supply at sink (or at main if no shut-off below sink).
Cut existing cold supply for T-fitting
Pipe cutter on cold supply line at planned T-fitting location.
Make two cuts spaced apart by T-fitting length (typically 2-3 inches).
Catch water in bucket — even with main off, residual water drains.
Install T-fitting
T-fitting is reducing tee: two 1/2 inch ends to existing supply, 1/4 inch outlet for new line.
Compression fittings on each side: slip nut and ferrule onto pipe, push fitting in, tighten.
Or PEX-to-copper transition with crimp ring on PEX, compression on copper.
Add mini shut-off valve at T-fitting
1/4 inch shut-off valve at the T-fitting outlet.
Compression fitting to T-fitting.
Allows isolating fridge supply for service.
Plumber's tape on threads.
Run tubing from sink to fridge
PEX (recommended): flexible, easy to route through cabinets.
Drill 1/2 inch holes through cabinet sides where line passes.
Run line behind base cabinets to fridge location.
Allow extra slack at fridge end (so fridge can be moved for service).
Don't kink line.
Connect line to shut-off valve at sink
Compression fitting on PEX or copper.
Tighten compression nut: hand + 1/4 turn.
Don't over-tighten.
Connect line to fridge
Fridge has a dedicated water connection on the back (typically 1/4 inch compression).
Connect tubing per fridge manual.
Apply plumber's tape on threads.
Restore water and test
Open main shut-off, then mini shut-off at T-fitting.
Listen for water flow at fridge.
Check all connections for leaks.
Run water through ice maker / dispenser.
Initial fill and discard first ice
Ice maker fills 24-48 hours after first connection.
Discard first batches (usually first 24-48 hours of ice).
Tubing can have residue from manufacturing.
24-hour leak check
Place paper towels under all connections.
Check next day.
Damp = slow leak; tighten further.
Dry = solid install.
Common mistakes that cost you
- Saddle valve install. Slow leaks over time. Use T-fitting.
- Kinked PEX line. Restricts flow, may fail. Smooth runs only.
- No shut-off at T-fitting. Can't isolate fridge for service. Always include shut-off.
- Drinking first ice. Manufacturing residue in tubing. Discard first 24-48 hours.
- Plastic tubing. Degrades, may leach. Use PEX or copper.
Frequently asked questions
Saddle valve OK for now until I do a proper install?
Acceptable as temporary; replace at first opportunity.
Saddle valves often leak after 1-3 years, sometimes catastrophically.
Plan to upgrade to T-fitting.
How long does the supply line take?
Standard install: 1-2 hours.
First-timers: 2-3 hours.
Professional: 1-1.5 hours.
Do I need a permit?
Single fridge water line: typically no permit (minor plumbing addition).
Major plumbing changes: plumbing permit required.
Verify with municipality.
When to call us instead
Fridge water line install is part of kitchen renovations. Our plumbers handle it as part of the scope.
Book a free 60-minute site visit →Related Ottawa services
If your kitchen needs more than fridge water line install, our kitchen renovation team handles full scope. Book a free 60-minute consultation.