This paper provides a comparative assessment of community-scale decentralized wastewater treatment systems (DEWATS) in Nepal, based on three communities in urban and peri-urban locations. The analysis provides lessons for sustainable and future replications of this approach, highlighting the benefits, drivers for long-term operation and maintenance, and barriers associated with up-scaling. Nepal is experiencing the fastest rate of urbanization in the South Asian region, while sanitation and wastewater management are emerging as some of the biggest challenges in urban areas. Over 43 per cent of the population still lacks access to a toilet, and virtually all wastewater and septage is discharged into water bodies without treatment. These mounting problems of urban sanitation demand urgent and appropriate solutions. The inherent simplicity of DEWATS provides an effective, affordable, and low-maintenance option for treating wastewater. This is particularly the case for low-income communities.