How to Replace a Water Heater Dip Tube
Updated February 25, 2026
Fix lukewarm hot water caused by a broken or deteriorated dip tube -- the plastic pipe inside the tank that directs cold water to the bottom for heating.
Overview
The dip tube is a plastic pipe inside the water heater tank that runs from the cold water inlet at the top down to within 6-8 inches of the bottom. Its job: push incoming cold water to the bottom where the burner or heating element heats it, so hot water stays at the top and flows to your faucets. When the dip tube breaks, cracks, or dissolves, cold water enters at the top and mixes directly with the hot water. The result: lukewarm water that never gets fully hot, no matter how high you set the thermostat. Replacing the tube takes under an hour and costs $8-$15.
What You'll Need
Safety First
- Turn off the gas (PILOT or OFF) or flip the electrical breaker before draining any water. Never drain the tank while the heating source is active.
- Water in the tank is 120-140°F. Use caution when draining and when removing the cold water inlet fitting -- hot water will flow out.
- The cold water inlet nipple on top of the tank requires a pipe wrench and significant force to unscrew. Brace the tank or have a helper hold it.
Step-by-Step Instructions
- Diagnose the Dip Tube
Classic dip tube symptoms: water starts hot at the faucet but drops to lukewarm within 1-2 minutes and stays there. Not cold -- lukewarm. That is cold water mixing with hot at the top of the tank instead of going to the bottom. Another telltale: small white or blue plastic flakes in faucet aerator screens and strainer baskets. Those are pieces of a deteriorating dip tube. If you see the flakes, the tube is dissolving.
Tip: Dip tube failures are most common in water heaters manufactured between 1993 and 1997. A batch of defective polypropylene tubes broke down in hot water and dissolved. If your heater is from that era and has these symptoms, the dip tube is almost certainly the cause. - Drain the Tank Partially
Turn off the heat source. Turn off the cold water inlet valve. Connect a garden hose to the drain valve and drain 3-4 gallons (not the full tank -- just enough to drop the water level below the cold inlet at the top). Open a hot water faucet somewhere in the house to break the vacuum. This prevents a full-tank flood when you disconnect the cold water inlet.
Tip: You do not need to drain the entire tank. Just lower the water level 6-8 inches below the top. This takes 2-3 minutes of draining. - Remove the Old Dip Tube
Disconnect the cold water supply line from the inlet nipple on top of the tank (the fitting marked COLD or on the right side when facing the front). Use a pipe wrench to unscrew the inlet nipple from the tank. The dip tube is attached to the bottom of this nipple -- it pulls straight out of the tank. If the tube is broken, the bottom portion is still in the tank. Reach in with needle-nose pliers or a coat hanger and fish out the broken piece.
Tip: If the old tube dissolved into small pieces, they are at the bottom of the tank mixed with sediment. Flushing the tank after installing the new tube will clear most of them. Remaining small fragments will eventually work their way to faucet aerators where you can clean them out. - Install the New Dip Tube
New dip tubes are cross-linked polyethylene (PEX) or heat-resistant polypropylene -- better materials than the old ones. The tube should be long enough to reach within 6-8 inches of the tank bottom. Most replacement tubes are pre-cut to 46-48 inches for standard 40-50 gallon tanks. Measure your old tube or the tank height and trim if needed. Insert the new tube through the inlet nipple opening. Wrap the nipple threads with Teflon tape (4-6 wraps) and screw the nipple back into the tank. Tighten with a pipe wrench -- snug plus one turn.
Tip: The new tube may have a small hole near the top. This is a cold water return port for recirculation systems. If you do not have a recirculation system, it does not matter -- the hole is above the hot water line and does not affect performance. - Refill and Test
Reconnect the cold water supply line. Open the cold inlet valve. Keep a hot water faucet open until water flows steadily with no air sputtering -- the tank is full. Close the faucet. Turn the heat source back on. Wait 30-60 minutes for the tank to reach temperature. Test: run the hot water at a faucet for 5 minutes. It should be consistently hot the entire time. No more lukewarm drops. Check faucet aerators over the next few weeks and clean out any remaining plastic fragments from the old tube.
Tip: Electric heaters: do not turn the breaker on until the tank is completely full and the hot faucet runs steady with no air. Elements running in a partially filled tank burn out within minutes.
Pro Tips
- Dip tubes cost $8-$15 and are available at any hardware store or online. Camco 11563 and Rheem SP11527C are the most common universal replacements. Bring your old one to the store to match the length and fitting size.
- While the cold inlet is off and the tank is partially drained, flush the remaining sediment. Open the drain valve and let it run until clear. Two maintenance tasks in one session.
- If your water heater is 10+ years old and the dip tube failed, consider whether replacing the entire heater makes more sense. A new 50-gallon gas heater costs $400-$800 installed. A dip tube replacement on an aging tank may just be the first of several failures.
- White plastic flakes from a deteriorated dip tube can clog shower heads, faucet aerators, washing machine screens, and dishwasher inlet valves. After replacing the tube, flush all faucets and clean all aerator screens.
- Some higher-end water heaters (Bradford White, commercial Rheem) have dip tubes with a curved bottom that creates a swirl effect inside the tank, improving heat transfer and reducing sediment. These cost $15-$25 but perform better.
When to Call a Pro
Call a plumber if the cold water inlet nipple is corroded and will not unscrew without risking damage to the tank, if the broken dip tube pieces are stuck inside the tank and you cannot retrieve them, or if the tank is old enough that the inlet threads are damaged (cross-threaded or stripped).
Frequently Asked Questions
When should I call a plumber to replace a water heater dip tube?
Call a plumber if the cold water inlet nipple is corroded and will not unscrew without risking damage to the tank, if the broken dip tube pieces are stuck inside the tank and you cannot retrieve them, or if the tank is old enough that the inlet threads are damaged (cross-threaded or stripped).
What are some expert tips to replace a water heater dip tube?
Dip tubes cost $8-$15 and are available at any hardware store or online. Camco 11563 and Rheem SP11527C are the most common universal replacements. Bring your old one to the store to match the length and fitting size. While the cold inlet is off and the tank is partially drained, flush the remaining sediment. Open the drain valve and let it run until clear. Two maintenance tasks in one session. If your water heater is 10+ years old and the dip tube failed, consider whether replacing the entire heater makes more sense. A new 50-gallon gas heater costs $400-$800 installed. A dip tube replacement on an aging tank may just be the first of several failures. White plastic flakes from a deteriorated dip tube can clog shower heads, faucet aerators, washing machine screens, and dishwasher inlet valves. After replacing the tube, flush all faucets and clean all aerator screens. Some higher-end water heaters (Bradford White, commercial Rheem) have dip tubes with a curved bottom that creates a swirl effect inside the tank, improving heat transfer and reducing sediment. These cost $15-$25 but perform better.
What tools do I need to replace a water heater dip tube?
You will need: Pipe wrench (for the cold water inlet nipple), Replacement dip tube ($8-$15), Teflon tape (for thread sealing), Garden hose (for partial tank drain), Needle-nose pliers (for fishing out broken tube pieces).
When should I call a professional instead of doing this myself?
Call a plumber if the cold water inlet nipple is corroded and will not unscrew without risking damage to the tank, if the broken dip tube pieces are stuck inside the tank and you cannot retrieve them, or if the tank is old enough that the inlet threads are damaged (cross-threaded or stripped).
How difficult is this project?
This project is rated intermediate. It requires moderate DIY skill and the right tools.
How long does this take?
Plan for approximately 45 - 90 minutes. First-timers may need extra time.
How much will this cost?
The estimated cost is $8 - $15 for the part. Costs vary by location and materials chosen.