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Groundwater remediation sites

Information about King County Industrial Waste Program approval for groundwater remediation sites.

About groundwater remediation discharges

Land with contaminated groundwater may undergo a remediation process, which partly consists of pumping out the groundwater and treating it to remove contaminates. Then the treated water may be disposed of into the sewerage system.

The King County Industrial Waste Program regulates wastewater discharges from groundwater remediation sites and requires discharge approvals.

Read the King County Public Rule that regulates discharge of groundwater to the sewer (259KB)

To discharge remediated groundwater to the county sewer system, follow the construction dewatering application process on the Construction dewatering authorization page. 

Sewer charges

Where applicable, sewer charges will be levied to those discharging groundwater to the KC sewer system.

Discharges from petroleum-contaminated soils have the following discharge screening levels:

Maximum concentration allowed in discharges
Parameter mg/l (ppm) µg/l (ppb)
Benzene 0.07 70
Ethylbenzene 1.7 1700
Toluene 1.4 1400
Total xylene 2.2 2200

Discharges during wet months

In order to be given permission to discharge to the sewer, those proposing discharges greater than 25,000 gallons per day (large-volume discharges) during the "wet months" (November through April) must show that it is not feasible to discharge to surface waters or to on-site subsurface infiltration systems.