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The supply line connecting your wall valve to your toilet tank is one of the most overlooked failure points in a bathroom. Plastic supply lines crack, rubber ones degrade, and when they fail — they fail at full pressure. A braided stainless replacement is cheap and takes 5 minutes. Here’s what to buy.
| Product | Best For | Price tier |
|---|---|---|
| Fluidmaster B1T16CS Click-Seal Braided Supply Line | Best Overall | Mid |
| BrassCraft S1-12DL F Stainless Toilet Connector | Best Hand-Tighten (Wing Nut) | Highest |
| Eastman 48088 Braided Toilet Connector, 12 in | Best Budget | Lowest |
Best Overall: Fluidmaster B1T16CS Click-Seal BraidedEditor’s Choice
Check the Fluidmaster B1T16CS Click-Seal price on Amazon →
Braided stainless over a polymer tube — burst-resistant, corrosion-proof, and flexible enough to fit any standard toilet-to-wall configuration. The 3/8″ compression x 7/8″ ballcock connection fits virtually every toilet made in the last 30 years. Available in 9″, 12″, and 16″ lengths.
- ✅ Stainless braid — burst resistant
- ✅ Fits virtually all toilets
- ✅ Multiple lengths available
- ✅ Budget-tier part
Best Hand-Tighten: BrassCraft S1-12DL F
Check the BrassCraft S1-12DL F stainless connector on Amazon →
Same 3/8″ compression x 7/8″ ballcock ends as the Fluidmaster, in a 12 in. length, but it comes with a wing nut you can finger-tighten at the tank — handy in a cramped space where a wrench will not swing. Reinforced PVC inner hose under the braid.
Best Budget: Eastman 48088, 12 Inch
Check the Eastman 48088 12 in. braided connector on Amazon →
The plain, cheap, do-the-job option: 7/8″ ballcock by 3/8″ compression, stainless braid over a PVC core, with nickel-plated solid brass hex nuts. Buy a couple and change every toilet in the house at once.
How to Replace a Toilet Supply Line
- Shut off the supply valve. Flush to drain the tank.
- Unscrew the supply line from the bottom of the tank and from the supply valve.
- Thread new line onto the supply valve (compression end) — hand tight plus 1/4 turn with pliers.
- Thread the ballcock nut onto the tank inlet — hand tight only (plastic threads strip easily).
- Turn water on slowly and check both ends for leaks.
Tip: If the line drips at the ballcock end, check that the rubber washer inside the coupling nut is present and not damaged before adding torque.
FAQ
What length supply line do I need?
Measure from the center of the wall valve to the center of the tank inlet. Buy the next size up — a little slack is fine, a line that’s too short creates tension and stress at the fittings. Sizing the ends is a separate question — see toilet supply line size.
My supply line is the corrugated chrome type. Should I replace it?
Yes — immediately. Corrugated chrome supply lines are one of the most failure-prone plumbing components ever made. Replace with braided stainless.
Bottom Line
Fluidmaster B1T16CS is the best money you can spend on a toilet. Replace every corrugated or plastic supply line in your home with braided stainless — it’s cheap insurance against a flooded bathroom.
If you’re changing the supply because the toilet is already off the flange, that’s the cheapest moment you’ll ever get to swap the toilet too — our picks are here.
Replace It on a Schedule, Not on Failure
A supply line is a few dollars and it is the only part of your toilet that can empty the mains into your house. It does not fail politely: it lets go at full pressure and keeps going until someone shuts the water off, which is a problem if the house is empty. The braided stainless ones are cheap enough that swapping them every several years — or whenever you are already working on that toilet — is simply better value than waiting to find out. What an unattended leak actually costs is priced out city by city in our 31-city leak-cost study.
Do Not Overtighten the Nuts
The most common way this job goes wrong. Both ends of a modern supply line seal with a rubber cone or gasket, not with thread compound and not with force. Hand-tight, then about a quarter turn with a wrench. Past that you are not making it tighter, you are distorting the gasket or cracking the plastic shank on the fill valve — and a cracked shank means you are now replacing the fill valve too. Tape and dope belong nowhere near either end.
Two Things to Check While You’re Down There
- The shut-off valve. If the angle stop under the toilet will not close fully, or weeps when you turn it, that is the more urgent repair — it is what you will be reaching for in an emergency. See shut-off valves worth fitting.
- The length. Measure from the stop to the fill-valve shank and buy slightly longer. A line pulled taut puts steady strain on both connections; a gentle curve puts none. Short gap under the tank? Eastman also make a 9-inch version — note it is their PVC-core, nylon-braid connector rather than the stainless-braided 48088 above, and Eastman rate it to a lower burst pressure: Eastman 9-inch toilet connector.
Check the stop valve while you are down there: if the old multi-turn valve will not close fully, a new line alone leaves you with the same problem next time. BrassCraft quarter-turn angle stop.
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