RELIABILT Toilet & Faucet Supply Lines
RELIABILT braided stainless steel and polymer supply lines for toilets, faucets, and dishwashers.
RELIABILT supply lines connect your shut-off valve to the toilet, faucet, or appliance, priced from $4 to $15 each. Braided stainless steel construction with polymer inner tube. Available in toilet (3/8" compression x 7/8" ballcock, 12" to 20" lengths) and faucet (3/8" compression x 1/2" FIP, 12" to 30" lengths) configurations. Replace every 8-10 years even if they look fine, as internal failure can cause catastrophic water damage.
Supply Line Sizes
| Toilet | 3/8" comp x 7/8" ballcock. 12" length is standard. $4-8. |
| Faucet | 3/8" comp x 1/2" FIP (female iron pipe). 16" or 20" for under-sink. $5-10. |
| Dishwasher | 3/8" comp x 3/8" comp with elbow. 48" or 60" length. $8-15. |
| Ice Maker | 1/4" comp x 1/4" comp. 10ft length. $6-10. |
How to Choose Supply Lines
Connection sizes: Before buying, identify both ends of the connection. Toilet supply lines are typically 3/8" compression on the valve end and 7/8" ballcock on the toilet end. Faucet supply lines are usually 3/8" compression on both ends or 3/8" comp x 1/2" FIP. Measure your existing connections or bring the old supply line to the store.
Length: Measure the distance between the shut-off valve and the fixture connection, then buy the next size up. A supply line that is slightly too long will curve gently; a supply line that is too short will strain the connections and leak. For toilets, 12" is standard. For faucets, 16" or 20" covers most under-sink distances.
Material: Braided stainless steel is the recommended choice. It resists bursting, kinking, and corrosion. Avoid older-style plastic or chrome-plated copper supply lines, which are more prone to failure. Braided stainless supply lines are the industry standard for new installations.
When to replace: Replace supply lines every 8-10 years as preventive maintenance. Also replace whenever you install a new toilet, faucet, or shut-off valve. A failed supply line can release 3-5 gallons of water per minute, causing severe water damage in a short time.
Tools needed: Supply line replacement requires only two adjustable wrenches (or a wrench and pliers) and a bucket to catch residual water. No pipe cutting, soldering, or specialized tools are necessary. This is one of the simplest plumbing jobs a homeowner can perform.
Installation tip: Hand-tighten the supply line nuts first, then add 1/4 to 1/2 turn with a wrench. Over-tightening can crack the fitting or strip the threads. Turn the water on slowly and check for drips. If a drip appears, tighten the nut an additional 1/8 turn. Repeat until dry.
Issues and Fixes
| Drip at valve connection | A drip at the compression fitting usually means the connection is not tight enough or the ferrule is damaged. Tighten the compression nut 1/4 turn with a wrench. If it still drips, shut off the water, remove the line, inspect the ferrule, and replace if it is deformed or scored. |
| Drip at fixture connection | At the faucet or toilet end, the rubber washer inside the coupling may be missing or misaligned. Remove the line, check for the washer, replace if needed, and hand-tighten plus 1/4 turn with a wrench. Do not over-tighten plastic fittings. |
| Kinked line restricting flow | Supply lines that are too long and forced into a tight bend can kink, reducing water flow. Replace with the correct length rather than trying to straighten a kinked line. A kinked braided line has internal damage even if the outer braid looks intact. |
| Bulging braided jacket | A bulge in the braided stainless outer jacket indicates the inner polymer tube is failing. Replace the supply line immediately. This is a burst risk. Do not wait for it to fail completely. |
| Wrong size purchased | Supply lines with mismatched connection sizes will not seal. If the nut threads onto the fitting but the connection drips, check that the connection types match exactly (compression vs FIP vs ballcock). A 3/8" compression nut will thread onto a 3/8" FIP fitting but will not seal properly without the correct washer. |
Supply line failures are preventable. The two most effective prevention measures are replacement on a regular schedule (every 8-10 years) and annual visual inspection of all accessible supply lines in the home.
Long-Term Care
Visual inspection: Check supply lines under every sink and behind every toilet once per year. Look for bulging, corrosion at fittings, drips, and moisture stains on the cabinet floor or wall. Catching a failing supply line before it bursts prevents thousands of dollars in water damage.
Exercise shut-off valves: Turn each shut-off valve off and on once per year to prevent it from seizing. A valve that does not close is useless in an emergency. If a valve is difficult to turn, replace it with a quarter-turn ball valve.
Replacement schedule: Replace braided stainless supply lines every 8-10 years regardless of visible condition. The inner polymer tube degrades over time and can fail without external warning signs. Mark the installation date on the line with a permanent marker.
Water damage prevention: Supply line failures are one of the top causes of residential water damage insurance claims. Consider installing water leak detectors near every toilet and under every sink. Smart leak detectors can send alerts to your phone and some can automatically shut off the water supply when a leak is detected.
After extended absence: If a home is unoccupied for more than a month, shut off the main water supply and consider shutting off individual fixture valves. A supply line failure in an unoccupied home can cause catastrophic damage before anyone notices. See all plumbing repair parts for related maintenance items.
Frequently Asked Questions
Do I need Teflon tape on supply line connections?
No. Supply lines use compression fittings or rubber washers to seal, not threaded pipe connections. Teflon tape is for tapered pipe threads (NPT). Adding tape to a compression fitting can actually prevent proper sealing. Use Teflon tape only on threaded connections like pipe fittings.
Can I reuse an old supply line when installing a new faucet?
Technically possible, but not recommended. Supply lines cost $5-10 and have a limited service life. A new faucet installation is the ideal time to replace supply lines. The small cost is negligible compared to the risk of a future failure with an aged line.
What is the difference between 3/8" and 1/2" supply lines?
The size refers to the connection diameter, not the tube diameter. Most residential fixtures use 3/8" compression connections at the valve. Some older faucets and commercial fixtures use 1/2" connections. Check your valve and fixture before purchasing. Adapters exist but add a potential leak point.
Supply line replacement is a basic DIY job. You may also need new shut-off valves if the existing ones are old gate-style valves. See all RELIABILT plumbing supplies.
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