The Skaneateles Lake Watershed Composting Toilet Project highlights the material and sociocultural challenges of developing new kinds of embodied practices that effectively utilize alternatives to traditional water-dependent plumbing. Practical, small-scale innovation is important to addressing the human dimensions of these changes, particularly given the widely held taboos informing discussion of what happens behind closed bathroom doors. In this example an innovative watershed policy placed composting toilets in seventy-five lakeside homes to prevent household blackwater from polluting an unfiltered drinking water source utilized by 250 000 people. Interviews with key informants and participating households illustrate the ways in which expectations of toileting practice sit in tension with the need to preserve the health of the local watershed, particularly over the long term. Understanding shifts in toileting practice must move past functional assessments of new or untested technology, taking into account sociocultural understandings of private, deeply embodied, yet resolutely pragmatic daily habits. As individuals seek to normalize new toilet technology as a part of daily routines, they encounter the body's materiality in ways that conflict with expectations of what belongs inside the home. In this case, the traditionally excluded effluence of the human body remains too close for comfort, forcing a renegotiation of the common boundary-making habits defining domestic space. The result is a shift in expectations about what of the body can or should belong in the home.