| Abstract | The majority of urban growth is associated with the rapid expansion of smaller urban centers and suburban development. Expansion of housing estates (HEs), the favored dwelling type particularly large cities in Thailand, has also followed the trend. Even the basic infrastructure provision has been moderately developed in suburban areas but sewerage system service is still lacking, thus individual onsite and small scale community centralized wastewater management are more preferable alternatives. However due to poor system function, results from water quality monitoring programs, cases complaint from people living around and previous research outcomes reveal that environmental impact from HE wastewater is major concern. To improve HE wastewater management (WWM) performance, this study aims at assessing WWM performance by using simple indicators, linking performance results to find significant factors influencing HE WWM performance, and assigning effective measures based on the performance and factors. The study investigated two different HE WWM systems, onsite and community centralized, in suburban area of Nonthaburi province, Thailand. HE organization questionnaire survey, in-depth interview with key informants, observation and relevant secondary data were used as source of information for this study. Performance assessment results for both systems showed that half of performance aspects still perform at poor level. Three significant factors influencing HE WWM performance were found in each WWM system through multiple regression analysis. For community centralized system, these factors are price of house, type of organization to manage HE and attitude of organization, while total house unit, direct experience on water pollution, and percentage of occupied house are the factors for onsite system. Appropriate environmental management measures (EMMs) which are compatible with identified key influencing factors, poor performance results, and institutional issues were proposed. The systematic approaches implemented in this study including assessing performance, identifying significant influencing factors and applying effective measures are expected to be beneficial for concerned agencies to develop policies or plans in WWM sector and may be applicable to environmental management in other sectors with adjustment to local context and improvement of indicators and postulated factors |