We identified only three studies dedicated to characterizing CH4 emissions from wastewater collection and treatment sources . It was more common for wastewater sources to be measured in campaigns targeting street-level leaks or a variety of sources . The studies identified several biogenic CH4 sources related to wastewater: manholes, sewers, pavement cracks, storm drains, a sewage vent pipe on a building, and wastewater treatment plants (WWTPs). There is a challenge in disambiguating some of these smaller point sources; stable carbon isotope 13 for CH4 (δ 13 C) -a common method used for attribution -can show mixed biogenic and natural gas source signatures , likely due to the co-location of emitting natural gas and sewage pipelines under city streets. CH4 enhancements attributed to flooded storm drains and sewers in were associated with rising urban water levels, suggesting that these emissions were intermittent. detected a CH4 plume from an anaerobic digester at one WWTP in SFBA. It is unclear if this plume was fugitive or a vent.