High cost of sewer systems usually restricts the sewage collection in rural areas. Many rural areas take traditional sewer scheme whose private-secondary-main sewer diameter is 110–200-300 mm without hydraulic calculation and increased the total cost of sewers. The rational utilization of small diameter sewers might contribute to sewer cost reduction. In this study, rural sewer length and cost models were established taking sewer diameter, household number, and length/width ratio of village as parameters to evaluate the cost benefits of using small diameter sewers. Hydraulic calculation of sewers was applied by Storm Water Management Model to ensure the small diameter sewers were feasible. The results indicate that household number and length/width ratio cause obvious impact on sewer length and cost. Main sewer with 200 mm diameter is suitable for the village with less than 1000 households. Using small diameter sewers can reduce the sewer cost by 6–15% compared with traditional sewer scheme and 110-110-200 might be the better scheme to rural areas because of the low cost (including construction cost and operation and maintenance cost) and high tolerance of sewage flow fluctuation. This study provided the suitable diameter of rural sewers based on cost model and hydraulic calculation which might be helpful for the application of rural sewers.

下水道系统的高成本通常限制了农村地区的污水收集。许多农村地区采用传统的下水道计划，其私有二级主干下水道直径为110-200-300 mm，而无需进行水力计算，并且增加了下水道的总成本。小直径下水道的合理利用可能有助于降低下水道成本。在这项研究中，以下水道直径，家庭人数和村庄的长宽比为参数，建立了农村下水道长度和成本模型，以评估使用小直径下水道的成本效益。通过雨水管理模型对下水道进行水力计算，以确保小直径下水道可行。结果表明，住户数量和长宽比对下水道长度和成本有明显影响。直径200毫米的主要下水道适用于少于1000户的村庄。与传统的下水道方案相比，使用小直径的下水道可以将下水道成本降低6-15％，并且110-110-200对农村地区可能是更好的方案，因为其成本低（包括建筑成本以及运营和维护成本）且成本高污水流量波动的容忍度。该研究基于成本模型和水力计算方法，为农村下水道提供了合适的直径，可能对农村下水道的应用有所帮助。与传统的下水道方案相比，使用小直径的下水道可以将下水道成本降低6-15％，并且110-110-200对农村地区可能是更好的方案，因为其成本低（包括建筑成本以及运营和维护成本）且成本高污水流量波动的容忍度。该研究基于成本模型和水力计算方法，为农村下水道提供了合适的直径，可能对农村下水道的应用有所帮助。与传统的下水道方案相比，使用小直径的下水道可以将下水道成本降低6-15％，并且110-110-200对农村地区可能是更好的方案，因为其成本低（包括建筑成本以及运营和维护成本）且成本高污水流量波动的容忍度。该研究基于成本模型和水力计算方法，为农村下水道提供了合适的直径，可能对农村下水道的应用有所帮助。