Definition of influent in English:



  • Flowing in.

    ‘some particles delivered in the influent streams settle in the reservoirs’
    • ‘The high sludge yields were caused by unexpectedly high and erratic levels of influent solids for which the builders were not responsible.’
    • ‘The influent waters carry not only solute loads, but also sediments both in suspension and along the bed of the streams.’
    • ‘The influent solution was sparged continuously with N2 gas to maintain anoxic conditions for the bacteria and to prevent aerobic oxidation of the materials in the wastewater.’
    • ‘Use at least a 4-inch diameter sewer line (also known as influent line or distribution pipe) from the house to the lagoon.’
    • ‘In case of the river Ganges, it is effluent in south-west while influent in the north of Calcutta.’
    • ‘Therefore, adjustments to the dosing system must be made when influent flows change substantially.’
    • ‘He was a fantastic racehorse and like a lot of Danehill's sons can become an influent sire.’
    • ‘Municipal water treatment plants must charge customers for the increased chemicals and electricity necessary for water treatment when influent raw water has high turbidity levels.’
    • ‘In summer, influent waters are commonly warm and enter the uppermost waters, but cooler rainwater falling at night may sink to the level of the thermocline before moving out into the basin.’
    • ‘The influent pump shaft acts as a lift station delivering raw sewage from a newly constructed 9.5-mile-long 18-foot diameter rock tunnel.’
    • ‘The reactor system includes a treatment basin having an inlet for continuously receiving an influent stream and an outlet for continuously discharging an effluent stream, and contains a mixed liquor.’


  • A stream, especially a tributary, which flows into another stream or lake.

    • ‘Good examples of influent streams include the Nile, and the Colorado River in the southwestern United States.’
    • ‘The method involves the steps of continuously flowing an influent into a treatment basin and continuously flowing an effluent out of the treatment basin into a clarifier.’
    • ‘In an extensive survey of U.S. wastewater treatment plants, Schulz has found perfluorinated compounds in influents and effluents.’
    • ‘Each system is designed to handle a certain volume of water per day, but the system is also tailored for the qualities of the specific influent.’
    • ‘This proves that the presence of ASP effluent in the Knostrop influent is not detrimental to settlement and that the Knostrop influent is capable of good settlement with proper operation.’
    brook, rivulet, rill, runnel, streamlet, freshet
    View synonyms


Late Middle English (as an adjective): from Latin influent- ‘flowing in’, from influere (see influence). The noun is recorded from the mid 19th century.