Domestic wastewater\" is the wastewater generated from residential sources. It originates from a wide range of residential, industrial, and commercial activities. In the HIQ database, the treatment options for this wastewater include: wastewater treatment plants. Domestic wastewater is produced by ordinary transformation activities. Generally treated as waste (non-recyclable), it requires further processing. Domestic wastewater can be modeled at two levels: treatment activities and market activities. The former refers to specific technologies/Hybrid technology for treating this waste, while the latter represents mixed processing. Two modeling methods are available for users to choose flexibly. When specific process assumptions are made for wastewater treatment, specific technology treatment activities can be selected. The collection and transportation of wastewater are considered in the use of sewer infrastructure in their respective market activities; the conveyance of wastewater through the sewer grid leads to losses before the wastewater enters the wastewater treatment plant. Direct emissions due to these losses are considered in the market activities. Losses are region-specific, so users are encouraged to check the regional modeling assumptions.