Safety first:Suspect natural gas, smoke, fire or an active CO alarm? Leave the area and follow local emergency guidance before troubleshooting. Gas / rotten eggsSmoke / burning
Odor family

Rotten-Egg & Sulfur Smells

A rotten-egg smell can point to very different sources. Odorized natural gas must be ruled out when plausible; otherwise, the location and timing of the odor help separate plumbing, hot-water and appliance causes.