Stiebel Eltron Water Heater Leaking

Common Symptoms

• Water dripping from the bottom or sides of the Tempra tankless unit
• Pressure relief valve discharge pipe dripping during or after a heating cycle
• Moisture at the inlet or outlet pipe connections on the Tempra
• SHC/SH: water pooling under the storage tank
• SHC/SH: rust-colored water or mineral deposits on the exterior of the tank
• DHC: water dripping from the compression fitting connections under the sink
• Any model: visible water staining on the wall behind the unit

Most Likely Causes

1. 1

   Pressure Relief Valve Dripping — Tempra

   The Tempra includes a pressure relief valve rated to discharge when pressure exceeds the set limit. In closed plumbing systems (those with a check valve or pressure regulator on the supply), thermal expansion during heating cycles can cause pressure to creep above the valve's set point, resulting in intermittent dripping. An expansion tank on the cold water supply line eliminates this. If the T&P valve drips continuously regardless of system pressure, the valve seat has debris or the valve has failed and must be replaced.

2. 2

   Inlet/Outlet Union Fitting Leak — Tempra

   Tempra units connect to supply and hot water piping via threaded union fittings. Seepage at the union connection indicates thread sealant has failed or was inadequate at installation. The fix is to disassemble the union, clean the threads, apply fresh Teflon tape plus pipe dope, and reassemble. Do not over-tighten plastic union nuts — finger-tight plus 1–2 turns with a wrench is sufficient.

3. 3

   Internal Module Seal Leak — Tempra (Post-Overheat/Scale)

   E1/E2 overheat events caused by heavy scale buildup can perforate the copper or stainless heating module walls. Water seeping from the body of the Tempra unit (not from a fitting or the T&P valve) indicates an internal module seal failure — scale has pitted or perforated the module wall. Minor perforation may be addressable with a descale flush; advanced perforation requires heating module replacement. Module replacement is an advanced repair — contact Stiebel Eltron technical support (1-800-STIEBEL).

4. 4

   T&P Valve Leak — SHC/SH Storage Tank

   The SHC/SH temperature and pressure relief valve discharges when water temperature exceeds 210°F or tank pressure exceeds the rated PSI. Intermittent dripping from the T&P discharge pipe in a closed plumbing system is caused by thermal expansion — install an expansion tank. Continuous discharge or failure to reseat after testing indicates a failed T&P valve that must be replaced. T&P valves should be replaced every 5–7 years regardless of visible condition.

5. 5

   Element Gasket Leak — SHC/SH Storage Tank

   The heating elements in SHC/SH storage tanks are sealed with a rubber gasket (element flange gasket). Gaskets degrade with age and heat cycling, causing seepage at the element flange visible near the access panel. A Camco 02162 gasket kit or equivalent is the correct replacement — scrape the old gasket residue cleanly from both the element flange and the tank opening, install the new gasket dry (no sealant), and torque the element bolts in a star pattern to 15–20 ft-lbs.

6. 6

   Anode Rod Port Leak — SHC/SH Storage Tank

   SHC/SH storage tanks include a magnesium or aluminum anode rod that protects the tank liner from corrosion. The anode rod threads into a port on the top or side of the tank. A slow drip at the anode rod hex fitting indicates the Teflon tape seal has failed. Close the cold water supply, drain a few gallons from the tank to drop pressure below the anode rod port, remove the rod, apply 3–4 wraps of Teflon tape plus a thin coat of pipe dope on the threads, and reinstall at 30–40 ft-lbs.

7. 7

   Tank Liner Corrosion — SHC/SH (Replace Unit)

   Water seeping from the tank body itself — not from a fitting, element, or valve — indicates the glass-lined steel tank has corroded through. This cannot be repaired. Rust-colored hot water is an early indicator. Full tank replacement is required. Deploying a new anode rod at the 2-year service interval prevents this in future units.

8. 8

   Valve Seat O-Ring or Compression Fitting Leak — DHC Point-of-Use

   DHC point-of-use units installed under a sink can develop leaks at the internal valve seat O-ring (a slow drip from the body of the unit) or at the compression fittings connecting the supply and discharge lines. Compression fitting leaks can be corrected by tightening the compression nut 1/4 turn; if the fitting is damaged, it must be replaced. Internal valve seat O-ring replacement requires disassembling the DHC unit — contact Stiebel Eltron support for the correct O-ring part.

Quick DIY Checks

1. 1Step 1 — SAFETY FIRST — turn off breaker and verify. Before touching any part of the leaking unit, turn off the dedicated breaker at the panel. Use a non-contact voltage tester on the wiring terminals inside the unit to confirm no voltage is present. Water and 240V is a lethal combination — never skip this step.
2. 2Step 2 — Identify the leak source. Dry the exterior of the unit thoroughly. Close the cold water supply valve to the unit but leave breakers off. Restore cold water supply slowly and observe where moisture first appears: top or side of Tempra (union fittings or T&P valve); element flange area on SHC/SH (gasket); anode rod hex fitting area (anode rod port); body of tank or Tempra module (corrosion or scale perforation — serious); compression fittings on DHC (fitting or O-ring).
3. 3Step 3 — Tempra T&P valve dripping: lift the test lever briefly — water should discharge and then stop cleanly when the lever is released. If the valve drips continuously after testing, replace it (same PSI rating as the original — check the data label). If the valve only drips during heating cycles, the system is likely closed (check valve or pressure regulator present) — install a Watts ET-15 or equivalent thermal expansion tank on the cold water supply. Measure supply pressure with a water pressure gauge to confirm supply pressure is below 80 PSI.

1. 4Step 4 — Tempra union fitting seepage: try gently snugging the union nut with an adjustable wrench (do not over-torque plastic union nuts — 1/4 to 1/2 turn past hand-tight is sufficient). If seeping continues, close the cold water supply, depressurize the line by opening a hot tap, and disassemble the union. Clean the male threads with a wire brush. Apply 3 wraps of Teflon tape in the thread direction, then a thin coat of pipe dope over the tape. Reassemble and restore supply — check for leaks.
2. 5Step 5 — Tempra internal module seal leak: if water seeps from the body of the Tempra (not from a fitting or T&P valve), shut off cold water supply and keep breakers off. This indicates scale perforation of the heating module following repeated E1/E2 overheat events. Attempt a descale flush first (see the Stiebel Eltron not-heating article for procedure using descale kit 234584). If the seep continues after descaling, the heating module must be replaced — contact Stiebel Eltron at 1-800-STIEBEL for a warranty module replacement (Tempra heating modules carry a 10-year warranty).
3. 6Step 6 — SHC/SH T&P valve test and replacement: turn the thermostat dial on the tank to the lowest setting. Test the T&P valve by lifting its lever — water should flow and then stop when released. If the valve drips after testing or discharges continuously, replace it. Match the rated temperature (210°F) and pressure (rated PSI on the tank data label). Thread the new valve with Teflon tape, install with a wrench (do not over-tighten), and attach a new discharge pipe that runs to within 6 inches of the floor.
4. 7Step 7 — SHC/SH element gasket replacement: with the dedicated breaker off and verified off, drain the tank to below the element level (open a hot tap and the tank drain valve until water stops flowing from the drain). Remove the element access panel and insulation. Disconnect the element wires. Use an element wrench (or large socket) to unscrew the element counterclockwise. Scrape all old gasket material from the element flange and tank opening. Install a new Camco 02162 or equivalent element gasket — use it dry, no sealant. Thread the element clockwise and torque in a star pattern to 15–20 ft-lbs. Reconnect wires, restore water (check for leaks before restoring power), restore breaker.
5. 8Step 8 — SHC/SH anode rod port leak: close cold water supply. Open a hot tap to relieve pressure. Locate the anode rod hex fitting (typically 1-1/16 inch hex on top of the tank — may be under a cover plate). Remove the rod. Inspect the threads for damage. Apply 3–4 wraps of Teflon tape plus a thin coat of pipe dope. Reinstall at 30–40 ft-lbs. Restore water and check for leaks. If the anode rod is depleted to a thin wire (less than 1/2 inch diameter), replace it with the correct Stiebel Eltron replacement anode.
6. 9Step 9 — DHC compression fitting or O-ring leak: turn off the 120V or 240V circuit to the DHC unit. Close the cold water supply valve under the sink. Inspect the compression fittings at the inlet and outlet: if hand-tight, snug the compression nut 1/4 turn with a wrench (do not over-tighten — plastic fittings crack). If the fitting is cracked, replace it. If water drips from the body of the DHC unit, the internal valve seat O-ring has failed — contact Stiebel Eltron support for the O-ring part number and replacement procedure.

Repair vs Replace

Recommended Tools & Parts

• Watts ET-15 Thermal Expansion Tank

  Thermal expansion tank for closed plumbing systems to prevent T&P valve dripping due to thermal expansion. Install on cold water supply line near the Tempra or SHC/SH unit.

  $30–$60

  Buy on Amazon →

• Camco 02162 Water Heater Element Gasket Kit

  Replacement element flange gasket for SHC/SH storage water heater elements. Use dry — no sealant. Torque bolts in star pattern to 15–20 ft-lbs to prevent warping.

  $8–$15

  Buy on Amazon →

• T&P Relief Valve (Match Rated PSI to Tank Data Label)

  Replacement temperature and pressure relief valve for SHC/SH storage tanks. Must match the rated PSI printed on the tank data label. Replace every 5–7 years as preventive maintenance.

  $15–$35

  Buy on Amazon →

• Pipe Thread Sealant (Pipe Dope) + Teflon Tape

  Use both Teflon tape and pipe dope together on all Tempra union threads and SHC/SH anode rod port threads for a reliable water-tight seal under pressure cycling.

  $8–$15

  Buy on Amazon →

Links are Amazon affiliate links (tag: fixitfastai-20). Prices are estimates.

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