King County Local Limits

In addition to federal limits on pollutants discharged in wastewater by industry, King County also imposes limits on certain pollutants. Local limits apply to all who discharge industrial wastewater to King County’s sewerage system.

To check both federal and local pollutant limits, King County Industrial Waste specialists may use a sampling device like that shown below being set up to sample wastewater from a manhole.

Examples of local limits are those set for heavy metals and cyanide, listed below. Heavy metals greater than permitted limits can upset or disable treatment plant operations. Also, heavy metals either pass through the plant into the effluent discharged to Puget Sound or accumulate in biosolids used to improve soils. 
 

Parameter	Daily Average Maximum	Instantaneous Maximum
	mg/l (ppm)	mg/l (ppm)
Arsenic	1.0	4.0
Cadmium	0.5	0.6
Chromium	2.75	5.0
Copper	3.0	8.0
Lead	2.0	4.0
Mercury	0.1	0.2
Nickel	2.5	5.0
Silver	1.0	3.0
Zinc	5.0	10.0
Cyanide	2.0	3.0

 

The metal limits are for total metals, not just dissolved metals. If a company discharges less than 5,000 gallons of wastewater per day, the company must comply only with the instantaneous limits.

A King County Public Rule specifies the local limits.

The photograph below shows an Industrial Waste investigator at an industrial facility taking a sample to test for metals.