Only a handful of studies examined CH4 emissions from residential end-use, finding that pilot lights and operating gas-fired appliances such as furnaces, water heaters, and stoves emit nontrivial amounts of CH4 . Saint-Vincent and Pekney (2020) integrated data from and to estimate that whole house and major appliance emissions could amount to 144.4 Gg CH4/yr emitted across the U.S. residential sector, accounting for ~2% of total U.S. natural gas emissions. While this suggests residential slip emissions are small in the context of other, mostly non-urban natural gas sources, our calculations in §3.1.2 indicate that slip could be a much more important source. For example, if slip contributes approximately 32.5% and 47.1% to total CH4 emissions in Los Angeles and Boston , respectively, then on the basis of mass slip emissions would total 127.9 Gg CH4/yr and 93.2 Gg CH4/yr in these cities. Combined, this estimate of slip emissions from two U.S. cities only is 1.5 times larger than Saint-Vincent and Pekney's (2020) estimate of total U.S. residential slip emissions. Similarly, scaled up measurements of CH4 emissions from pilot lights and operating appliances in 75 California homes to estimate that 35.7 Gg CH4/yr is emitted from residential natural gas use across the state. Our calculation for potential slip emissions in Los Angeles alone is 2.6 times larger. We note that these are not direct comparisons, as the estimates for CH4 emissions that correlate with metered natural gas use in Los Angeles and Boston include emissions from the commercial and industrial and commercial sectors in addition to residential. However, unless commercial and industrial slip dominate total slip emissions in cities, emissions from residential slip may be largely underestimated across the U.S. Higher natural gas use in the residential and commercial sectors in winter that overlaps with elevated city-level CH4 emissions rates may signal that the majority of slip emissions in cities is tied to using natural gas for space or water heating, cooking, or other purposes in these sectors (e.g., see . Commercial and industrial end-use sources were not targeted in the studies, although passive CH4 detections from a light rail train suggest these types of sources are emitting . Further investigation of end use sources is warranted. Studies in other cities globally can inform future research targets such as compressed natural gas vehicles and heating, cooking, and other CH4 emissions from festivals and events , among others.