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The right toilet supply line must fit both the shutoff valve and the toilet fill valve, reach between them without strain, and be installed according to its own instructions. A common documented pairing is 3/8-inch compression at the shutoff valve and 7/8-inch ballcock at the toilet, but check both connections before buying.
What size toilet supply line do you need?
Match the two ends separately: identify the shutoff-valve outlet and the toilet fill-valve inlet. BrassCraft documents a flexible braided polymer connector with a 3/8-inch compression inlet and a 7/8-inch ballcock outlet for a standard toilet connection. This is a common configuration, not a guarantee that it fits every home. Fluidmaster lists other inlet configurations as well.
Check the existing connector and fittings, but verify the actual connections rather than relying on appearance alone. If the shutoff end differs from the common 3/8-inch compression fitting, choose a connector made for that valve outlet.
How to choose a replacement line
Match both end connections
Confirm that the supply line’s valve end fits the shutoff and its toilet end fits the fill valve. Do not assume both ends use the same fitting or that every toilet uses the same configuration.
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- UNIVERSAL FLEXIBLE TOILET CONNECTOR: The Eastman Braided Toilet Connector is the standard in bathroom supply lines. This 12 in. flexible supply hose is equipped with 7/8 in. Ballcock x 3/8 in. Compression connections
- DURABLE: This Steel-Flex toilet connector is constructed of highly durable PVC core, a multi-filament braided nylon reinforcement, a clear vinyl outer shell and a grade 304 braided stainless steel exterior. Designed to prevent kinking and crimping
- EASY TO INSTALL: Equipped with full-flow brass barbs, 7/8 in. Ballcock by 3/8 in. Compression nickel-plated solid brass hex nuts for quick and easy installation, does not require any soldering, glue, or crimping
- RELIABLE: This connector is designed to withstand many hours of use. UPC, CSA, AB1953, NSF and Lead-Free for non-potable water applications
- SPECS: Toilet connector has a working pressure of 125 PSI and a working temperature of 40 degrees F to 150 degrees F; can withstand a burst pressure of 2500 PSI and a maximum temperature of 180 degrees F
Measure the route and choose a usable length
Measure the path between the connections and choose a line long enough to route without tension, sharp bends, or kinking. Fluidmaster’s Click Seal product sheet lists examples in 9-, 12-, and 20-inch lengths, as well as a universal connector with adapters for several inlet sizes. Available lengths and fittings vary by product, so check the specific model before purchase.
Check construction, limits, and location
Construction and extra features alone do not establish that a connector is more reliable or will prevent leaks. For its cited braided polymer connector, BrassCraft specifies use in accessible locations in potable-water distribution systems and a maximum pressure rating of 125 PSI. Check the selected model’s own specifications and installation instructions; do not assume those limits apply to other lines.
Rank #2
- Manufactured in China
- Easy to use
- Highly durable
- 12-Inch length
- 3/8-Inch compression by 7/8-Inch ballcock
Treat special installation features as product-specific
Fluidmaster’s Click Seal nut is designed to click when its specified connection is sealed. That feature belongs to the Click Seal product; it does not describe how to install every connector. Fluidmaster’s product material says, “the ‘click’ lets you know it’s sealed.” This is a manufacturer description, not independent comparative testing.
How to install the line and check for leaks
Use the instructions supplied with the exact connector you purchase. For the cited Fluidmaster Click Seal product, the manufacturer’s directions are:
Rank #3
- BRAIDED TOILET CONNECTOR: Flexible 16 in hose provides a secure connection between the toilet tank and shut-off valve; features 7/8 in ballcock inlet x 3/8 in compression outlet
- DURABLE MULTI-LAYER CONSTRUCTION: Built with a PVC core, nylon reinforcement, vinyl outer layer, and stainless steel braided jacket for long-lasting flexibility
- TOOL-FREE INSTALLATION: Designed with full-flow brass barbs and compression fittings for a fast setup—no soldering, adhesives, or special tools required
- RELIABLE PERFORMANCE RANGE: Handles working pressures from 125 PSI to 2500 PSI; suitable for temperatures from 40 degrees F to 150 degrees F, with a maximum of 180 degrees F
- CERTIFIED FOR NON-POTABLE SYSTEMS: Approved by UPC, NSF, CSA, and AB1953 standards for use in non-drinking water applications
- Turn off the water at the shutoff valve.
- Remove the old connector and clean all connector threads.
- Install the metal nut onto the shutoff valve and tighten it one-half turn beyond hand-tight.
- At the specified Click Seal end, align the threads and hand-tighten until the nut clicks.
- Slowly turn the water back on.
- Carefully inspect the shutoff-valve connection for leaks. If it leaks, tighten only enough to stop the leak; do not overtighten.
These steps are specific to the cited Click Seal instructions, not universal directions for other connectors. If a joint continues to leak or the shutoff valve appears damaged, the manufacturer materials cited here do not diagnose the cause; consider getting help from a qualified plumber.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What product information can—and cannot—tell you
BrassCraft and Fluidmaster provide product specifications and installation directions, but those materials do not establish a universal best supply-line material, independent reliability rankings, comparative failure rates, or guaranteed leak prevention. They also do not establish local code compliance for a particular installation. Choose by confirmed fitting compatibility, adequate measured length, stated product limits, and the instructions for the exact model.
Quick Recap
Best Value
- 2 Pack 16-inth length connector with 3/8 in. compression connection to water shut-off valve
- Connects to standard toilet 7/8 in. ballcock inlet, hand-tighten wing nut for quick and easy connection
- Bends freely, without kinking or crimping, installation is easier, especially in cramped quarters
- External corrosion resistance to common household, tile and glass cleaners
- 8-sided pneumatic crimp for greater dependability and reliable nut-to-hose connections
Rank #4
- 2-Pack 12-inth length connector with 3/8 in. compression connection to water shut-off valve
- Connects to standard toilet 7/8 in. ballcock inlet, hand-tighten wing nut for quick and easy connection
- Bends freely, without kinking or crimping, installation is easier, especially in cramped quarters
- External corrosion resistance to common household, tile and glass cleaners
- 8-sided pneumatic crimp for greater dependability and reliable nut-to-hose connections
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