Step 1: Where does the smell show up?

• Clothes washed in hot water smell → Go to Step 2 (Water Heater Check)
• Clothes washed in cold water smell → Go to Step 3 (Water Supply Check)
• Both hot and cold smell → Go to Step 4 (Washing Machine Check)

Step 2: Water Heater Check

• Run only hot water from a sink/shower.
  • Does the hot water itself smell like rotten eggs?
    • Yes → Water heater issue (likely anode rod reaction or bacteria).
      • 🔧 Flush tank.
      • 🔧 Check/replacement of anode rod (aluminum-zinc or powered rod).
      • 🔧 Refer to manufacturer's O&M before using chlorine/cleaners.
    • No → Move to Step 4 (Washing Machine Check).

Step 3: Water Supply Check

• Run cold water directly from faucet/outdoor spigot.
  • Does the cold water smell?
    • Yes → Water supply is contaminated with sulfur bacteria.
      • 🔧 If on well water → test for bacteria/sulfate. Consider shock chlorination.
      • 🔧 If on municipal water → contact supplier.
    • No → Smell is isolated to the washer → Go to Step 4.

Step 4: Washing Machine Check

• Run an empty rinse cycle (no clothes, no detergent).
  • Does the drum smell when cycle finishes?
    • Yes → Machine buildup (biofilm, drain, detergent residue).
      • 🔧 Deep clean with manufacturer-approved cleaner.
      • 🔧 Clean gasket, dispenser tray, and drain filter.
      • 🔧 Keep door open after cycles.
    • No → Smell may be from plumbing drain line (sewer gas).
      • 🔧 Check washer drain hose connection and p-trap.

Step 5: Still Unsure?

If after flushing/cleaning the odor remains:

• Smell strongest in hot loads → Call plumber to service water heater.
• Smell strongest in cold loads → Test water supply.
• Smell strongest only in laundry → Service the washing machine.