Unsafe management of household wastewater is a persistent challenge in rural and low-resource areas of the U.S. and other high-income countries (Maxcy-Brown et al., 2023). One illegal but nevertheless widespread alternative in the U.S., primarily in rural areas where soil or geological conditions are incompatible with the operation of conventional septic systems, is “straight-piping.” Straight-piping is the direct discharge of untreated wastewater from homes, typically into a ditch or lower-elevation area adjacent to the home. In the “Black Belt” region of central Alabama, sewer is available to roughly 50% of residents; the rest are expected to install and maintain a permitted onsite wastewater treatment system [OWTS). However, the confluence of impermeable shrink-swell clays that preclude the use of conventional septic systems, along with a high proportion of low-income residents who are unable to afford advanced, engineered OWTS, leads to widespread straight piping. Field surveys have shown that a substantial proportion of unsewered homes in the Black Belt use straight pipes (Maxcy-Brown et al., 2021); we use a conservative estimate of 35% straight pipe use among unsewered households in the 17-county region (not including the highly urbanized Montgomery County). We estimate that over 20,000 homes in the Alabama Black Belt have straight pipes that discharge over 3.7 million gallons of raw sewage per day into watersheds that drain to the Gulf. Using average concentrations in household wastewater, this represents approximately 7800 pounds of biochemical oxygen demand (BOD), 1100 pounds of nitrogen, and 200 pounds of phosphate per day, in addition to hundreds of billions of infectious pathogens, endocrine disruptors, pharmaceuticals, and other contaminants. This presentation will contribute estimates of the nature and extent of straight pipe contamination of the Gulf watersheds and enable comparison of the relative magnitudes to other sources of contamination.