How to Replace a Sink Sprayer or Supply Line

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Three different under-sink parts get lumped together under the word “hose,” and swapping the wrong one wastes a trip to the store. A side sprayer is the separate spray head that sits in its own hole next to a kitchen faucet, fed by a hose that taps into the faucet body at a diverter. A pull-down hose is the retractable line inside a modern single-handle faucet that the spray wand rides on. A flexible supply line is the short braided tube that carries water up from the shutoff valve to the bottom of the faucet. This guide covers all three of those swaps. It stops short of pulling and resetting the whole faucet, which is a different and larger job covered in our guide on installing a new faucet (192).

All three swaps stay on the homeowner side of the line for the same structural reason: every connection here is a threaded coupling or a gasketed nut that you close by hand and finish with a light turn of a wrench, and you take the pressure off first by shutting the stops under the sink. Nothing screws into a wall or carries a permanent water load. Two related fixes sit just outside this post: if the shutoff (angle stop) valve itself drips or will not close, that valve is its own replacement, covered in our guide on replacing toilet supply lines and shutoff valves (196). If water is coming from the drain or P-trap under the sink rather than the supply side, see our guide on fixing a leaking sink drain (033).

Side Sprayer vs Pull-Down Hose vs Supply Line: Three Different Under-Sink Parts

Match the part to the symptom before you buy anything. A weak or dead side sprayer, or one that leaks at the head, points to the side-sprayer head and its hose, which connect to a diverter inside the faucet body. A pull-down wand that sticks, retracts poorly, or splits points to the pull-down hose and its quick-connect coupling. A wet spot under the cabinet that traces back to the small tube between the shutoff valve and the faucet points to the flexible supply line.

These are separate parts with separate connections, so the fix for one is not the fix for another. Cleaning or replacing the screen at the tip of the spout is a different part again, the aerator, covered in our guide on cleaning a faucet aerator (024). Stopping a steady drip from the spout usually means the internal cartridge, not any hose, and that lives in our guide on replacing a faucet cartridge (025). Knowing which of the three parts you are touching is the whole reason this job goes smoothly or turns into guesswork.

Replacing a Side Sprayer Head and Hose at the Diverter

A side sprayer connects to the faucet at a diverter, and that diverter is the part that controls how much water reaches the sprayer. The diverter is a small spring-loaded valve inside the faucet body. According to repair references from Hunker and DoItYourself.com, when you squeeze the sprayer trigger, the pressure drop pulls a plunger over and routes water out to the sprayer hose; when you let go, the spring sends flow back to the spout. That mechanism matters for one reason: a sloppy swap that kinks the hose or disturbs the diverter is the usual cause of a sprayer that runs weak afterward.

To replace the head and hose, close both supply stops under the sink and open the faucet to relieve pressure. The sprayer head unscrews from the hose at a coupling under the sink, where the hose threads onto a nipple at the bottom of the faucet body. Unthread the old hose at that connection, feed the new hose up through the sprayer mounting hole, and thread it back onto the same nipple. Hand-tighten the coupling, then snug it lightly with a wrench. Run the sprayer before you reassemble anything else. If pressure is weak, the hose may be kinked along its run or the diverter may be clogged with mineral debris, which Signature Hardware lists among the common causes of a weak sprayer. A diverter buried deep in the faucet body that will not clear is where this job ends for most homeowners, since reaching it means partially dismantling the faucet.

Reconnecting a Pull-Down Hose at the Quick-Connect Without Kinking It

A pull-down hose attaches to the faucet through a quick-connect coupling, and getting that coupling fully seated is the single thing most people get wrong. Manufacturer instructions from Moen describe pushing the quick-connect end onto the fixed outlet until you hear or feel an audible click, which is the signal that the locking collar has engaged. A connection that is not clicked fully home can leak or pull loose under the weight of the wand.

Close the supply stops and disconnect the old hose first. Quick-connects release by pushing the outer housing up toward the faucet body while squeezing the locking tabs or pressing the release button, then pulling the hose straight down. When you fit the new hose, route it so it falls straight down through the spout and back without looping tightly around the supply lines or the drain tailpiece, since a tight loop is what makes a pull-down wand retract poorly or stick. Moen’s instructions also call for installing the hose weight onto the hose on the spray-wand side, a few inches up from the bottom. That weight is what pulls the wand back into the spout, so skipping it or clamping it in the wrong spot leaves you with a wand that will not retract. Pfister and Danze use similar quick-connect couplings, so check your faucet maker’s parts page for the exact clip style before you buy a replacement hose.

Sizing and Choosing a New Flexible Supply Line (Length and Fitting Type)

The two ends of a supply line rarely use the same fitting, and matching each end to what it connects to is the part generic “just replace your supply line” advice skips. The shutoff valve (the angle stop) under the sink almost always takes a 3/8-inch compression connection. The faucet end is different: many kitchen faucets accept a 1/2-inch FIP (female iron pipe) thread, while others take a 3/8-inch compression connector. Retailer and manufacturer listings from Home Depot, Lowe’s, Menards, and Eastman show the common kitchen line stamped 3/8-inch compression on one end and 1/2-inch FIP on the other, which is why you buy by the pair of fittings, not by length alone. Take the old line to the store, or read the stamped sizes off the nuts, so you walk out with the right connectors on both ends.

Length is the second decision, and it is easy to get wrong in the other direction. A line that is too short strains the connections and pulls them out of square; a line that is too long has to loop or kink to fit. Standard braided lines come in lengths such as 12, 16, 20, and 30 inches, per those same retailer listings, with shorter lengths common under bathroom sinks and longer ones under kitchens. Pick a length that reaches from the stop to the faucet shank with a gentle curve and no tight bends. Braided stainless steel lines resist bursting and bending fatigue better than older bare-tube types, which is why they are the standard replacement today. Choosing the faucet itself, as opposed to the line that feeds it, is a separate decision covered in our guide on choosing a kitchen or bathroom faucet (027).

Swapping a Supply Line Between the Angle Stop and the Faucet Shank

A braided supply line seals with a rubber gasket, so it needs far less force than people expect, and overtightening is the most common way to ruin the new line. Family Handyman and Fluidmaster both describe the method: thread the nut on by hand until it stops, then add only about a half turn with a wrench. The gasket does the sealing, and cranking past that point can crush the gasket or distort the ferrule and cause the very leak you were trying to stop.

To swap the line, close the shutoff valve and open the faucet to drain the pressure and the water still in the line. Place a small bowl or rag under the connections, since a little water will spill. Unthread the line at the faucet shank first, then at the angle stop. Thread the new line onto the faucet shank by hand, then onto the stop, making sure both nuts start straight and do not cross-thread. Snug each with the half-turn rule. Note that this is the sink supply line; the toilet supply line and the under-tank shutoff are a separate job, covered in our guide on replacing toilet supply lines and shutoff valves (196). If the angle stop itself is seized or weeping when you try to close it, stop and treat that valve as its own replacement rather than forcing it.

Leak-Checking the Sprayer Diverter and Both Supply Connections

Turn the water back on slowly and watch every connection you touched before you call the job done. Open the shutoff valves gradually rather than snapping them open, then check the faucet shank connection and the angle-stop connection for beading or dripping. The EPA’s WaterSense program suggests running a finger around each gasket and fitting and looking for any moisture on the outside of the pipe or nut, since a slow weep shows up as a damp film before it ever drips.

Run the faucet and the sprayer through their full range while you watch. Cycle the side sprayer or pull-down wand on and off several times so the diverter and the hose see real pressure, and look underneath for any drip at the diverter nipple or the sprayer coupling. If a supply connection weeps, add a small additional snug rather than a hard crank, and recheck. For a connection you cannot see clearly into the cabinet, the WaterSense meter test catches a slow hidden leak: read your water meter, wait two hours with no water used, and read it again; any movement means water is escaping somewhere. A sprayer that now runs weak after the swap almost always traces to a kinked hose along its path or a diverter that needs clearing, not to the part you replaced, so reseat the hose run before you assume the new part is faulty.

Frequently Asked Questions

Do I need to turn off the water to replace a sink supply line?
Yes. Close both shutoff valves under the sink and open the faucet to relieve pressure before you unthread anything. Shutting off water to a single fixture is its own short task with its own steps.

Why is my sink sprayer weak after I replaced the hose?
Most often the hose is kinked somewhere along its run, or the diverter inside the faucet is partly clogged with mineral debris. Reseat the hose so it hangs without a tight loop, and if the diverter is the problem, it usually needs clearing or replacing inside the faucet body.

How do I know what size supply line to buy?
Read the stamped sizes off the old line’s nuts, or take the old line to the store. The angle-stop end is usually 3/8-inch compression, while the faucet end is often 1/2-inch FIP or 3/8-inch compression. The two ends frequently differ, so match each one.

How tight should a braided supply line be?
Hand-tight, then about a half turn with a wrench. The rubber gasket does the sealing. Overtightening crushes the gasket and tends to create a leak rather than stop one.

Can I reuse the old supply line if it still looks fine?
It is better to install a new line when you have the connection open. The gasket and braiding age, and a line that has been compressed and re-flexed is more likely to weep at the gasket when you reseat it.

This article is general information, not professional advice. Plumbing connections involve water under pressure and the risk of property damage, so if anything is outside the clearly safe steps described here, consult a licensed plumber.

Sources

  • U.S. Environmental Protection Agency, WaterSense, Fix a Leak Week: https://www.epa.gov/watersense/fix-leak-week
  • Moen, How to Install a Pullout or Pulldown Hose: https://solutions.moen.com/ArticleLibrary/HowtoInstallaPulloutorPulldownHose
  • Pfister, Pull-down, Pull-out Hose Troubleshooting: https://www.pfisterfaucets.com/parts-support/troubleshooting/support-articles/pull-down-pull-out-hose
  • The Home Depot, BrassCraft 3/8 in. Compression x 1/2 in. FIP Braided Faucet Supply Line: https://www.homedepot.com/p/BrassCraft-3-8-in-Compression-x-1-2-in-FIP-x-30-in-Braided-Polymer-Faucet-Supply-Line-B1-30A-F/100186760
  • Eastman, Compression Braided Faucet Connector: https://www.eastmanplumbing.com/us/en/stop-valves-supply-lines/supply-lines/faucet-supply-lines/compression-braided-faucet-connector-0
  • Family Handyman, Stop Leaks in Plumbing Joints: https://www.familyhandyman.com/project/how-to-tighten-water-supply-line-connectors/
  • Fluidmaster, Water Supply Connectors Instructions and FAQs: https://fluidmaster.com/toilet-problems/instructions-faqs-click-seal-supply-lines/
  • Hunker, How to Fix or Replace a Kitchen Sink Sprayer: https://www.hunker.com/13769423/how-to-fix-or-replace-a-kitchen-sink-sprayer/
  • Signature Hardware, Faucet Sprayer Troubleshooting: https://support.signaturehardware.com/hc/en-us/articles/4403236223252-Faucet-Sprayer-Troubleshooting

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