If generated purge water (resulting from well installation, developing, sampling, pumping tests, groundwater monitoring, decanting of saturated soils during drilling activities, etc.) is a listed or a characteristic hazardous waste it may not be poured on the ground or back to the well. In this case contaminated water should be conducted to a water treatment plant. If analysis of the water determines that it is not hazardous waste and it meets ground water standards or health based standards, it may be poured on the ground at or near the point of generation, but not back to the well. Discharges to surface water or drainages should be avoided because of stringent aquatic life water quality standards. Where there is prior approval, discharges directly through an on-site sanitary sewage system may be allowed.
Water generated from dewatering IDW must be managed as a separate waste. In this case, water must be containerized upon generation. A separate waste determination is required. If analysis of the water determines that it is not hazardous waste and it meets ground water standards or health based standards, the water may be poured on the ground at or near the point of generation. If water is contaminated but its quantity, chemical composition and pollutants concentrations meet the stated quality/quantity requirements for generated sanitary/production wastewater it could be discharged into an on-site sewage system. If generated water is determined as hazardous waste it has to be treated accordingly for recycling in an in situ or ex situ waste water treatment plant.
It is recommended to minimize the initial generation of contaminated water because there may be a large amount of contaminated water to containerize for analysis and characterization.