In recent years, shared facilities have contributed substantially to increased access to sanitation in urban areas. While shared sanitation is often the only viable option in densely-populated, low-income urban areas, it is currently considered a "limited" solution by the international community. In this paper, we analyze the conditions under which shared sanitation could be considered of adequate quality and propose a set of indicators associated with sanitation quality to be included in national household surveys. We conducted a survey with 3600 households and 2026 observational spot-checks of shared and individual household toilets in Kisumu (Kenya), Kumasi (Ghana), and Dhaka (Bangladesh). We develop a composite sanitation quality outcome measure based on observational data. Using regression analysis, we identify self-reported indicators that correlate with the spot-checked composite measure and are, therefore, robust with regard to reporting bias. Results show that (pour-) flush toilets are a highly informative indicator for sanitation quality compared to other toilet technologies. In contrast to previous arguments and depending on the context, sharing a toilet has a comparatively lower correlation with sanitation quality. Toilets still show good quality if shared among only 2-3 households. Toilet location and lighting, as well as the presence of a lockable door, are equally strong indicators for sanitation quality and could serve as alternative indicators. The findings suggest that the sanitation service levels defined by the WHO and UNICEF might be reconsidered to better capture the quality of sanitation facilities in low-income urban settlements.