Dip Tube Inspection

August 4, 2009



Some water heaters have side inlets near the bottom of the tank and do not use dip tubes.

Water heaters with a top inlet use a dip tube that extends from the inlet of the heater to approximately 8 inches from the bottom of the tank. When water is heated, it expands thus causing it to rise. The dip tube routes the incoming “cold” water to the heat source at the bottom of the tank. This also deters the incoming water from cooling the existing hot water thereby providing optimal efficiency.

Dip tubes may disintegrate. When this occurs, small plastic particles can often be found in faucet aerators. This can lead to erratic or diminished water flow from the faucets. As the condition of the dip tube worsens, the temperature of the hot water from the heater will continue to decrease.

Although the quality of dip tubes have substantially improved, they are subject to failure.


Dip Tube Replacement / Inspection

Replacing the dip tube isn’t complicated. However, there may be some obstacles that hinder the process. Many heaters are installed in confined areas offering little work room. This may require the removal of the heater. The instructions below do not detail the removal or installation of the water heater.

If the inlet and outlet on the heater were soldered or “hard piped” to the water lines rather than connected with readily removable supply line connectors, the job will require advanced skill and should not be attempted by other than a professional.


Please read all steps completely prior to performing this procedure to assure proper preparedness.


Tools / Equipment needed :

  1. Eye protection
  2. Protective gloves
  3. Breaker box lock out kit (for electric water heater applications without a readily accessible cut-off switch)
  4. Quality garden hose capable of withstanding high water temperatures
  5. #2 Flathead Screwdriver
  6. Small mill or bastard file
  7. Adjustable wrench
  8. Channel-lock pliers
  9. Needle-nose pliers
  10. 10″ or 12″ Pipe wrench
  11. Wire brush

Materials needed:

  1. New dip tube
  2. New washer for flex connector
  3. Thread sealant – heat tolerant
  4. 3/4″ nipple, brass preferably (may not be required)

Procedure :

(The following procedure is detailed for water heaters connected with readily removable supply lines) :

(1) Perform steps 1-8 in the Flushing Procedure.

(2) Remove the inlet supply from the inlet nipple by unscrewing (counterclockwise) the hex-nut at the base of the flexible supply line. Be careful to avoid kinking the supply line. Kinking the supply line will restrict water flow and may damage the line. If damaged, the supply line will need to be replaced and may require professional assistance.

Remove the rubber washer from inside the hex-nut of the flexible connector. Thoroughly clean the internal threads with a wire brush and remove any residual debris. Insert the new washer into the hex-nut.

(3) Use your pipe wrench to remove the inlet nipple. Mineral deposits and/or oxidation may hinder its removal and may require excessive force.

(4) Upon removal of the nipple, the remaining portion of the dip tube should be accessible and removable with needle-nose pliers. Sometimes the dip tube is attached to the nipple and comes out upon removal of same. In extreme cases, the dip tube may be seized in the heater and may require a thread extractor for its removal.

(5) Once the dip tube is removed, the inlet should be externally cleaned to remove any mineral deposit or rust.

(6) The new dip tube should be measured and trimmed (if necessary) per the dip tube manufacturer’s instructions.

(7) Install the new dip tube by inserting it into the inlet. Inspect to assure the dip tube has seated properly. If the new dip tube came attached to a new nipple, proceed to step 9.

(8) If the old nipple is usable, clean the nipple thoroughly with a wire brush inside and out. Inspect the threads for any burrs. Any burrs on the outer threads should be filed accordingly.

(9) Apply a very light coat of thread sealant onto the lower threads of the nipple. Never apply sealant to female threads.

(10) Thread the properly prepared nipple into the water heater inlet and tighten.

(11) Apply a very light coat of thread sealant to the exposed threads of the nipple.

(12) Connect the flexible connector to the inlet nipple and tighten. Again, be careful to avoid kinking the flexible connector.

(13) Resume steps 9-14 in the Flushing Procedure. It may be necessary to repeat these steps to flush all passable remnants of the dip tube.

Furthermore, faucet aerators may continue to become clogged for some time until all of the particles have passed through the system.

Some remnants of the dip tube may not be retrievable and may cause problems for some time. Should this occur, AAA AUGER strongly recommends that the water heater be replaced.


Related Links :

Flushing the Water Heater
Temperature & Pressure Valve Inspection
Anode Rod Inspection