April Hardy February 2026
TireDunker
Wastewater:
Inspection Findings
and Pollution
Prevention
Outline
1.Sitemaps and Inspections
2.Tire Dunker Water Disposal Practices
3.Violations Identified
4.Required Corrective Actions
5.Key Inspection Focus Areas
6.Recommended Next Steps
7.Follow-up Inspection Findings
8.Questions and Discussion
Sitemaps and Inspections
Create a sitemap for the
inspection
The tire dunker was
located next to CB #3
The connection of CB #4
was suspected to be
connected to the sewer,
but records did not verify
this
Dye testing was performed in both CB #3 and #4 using two
different colored dyes
(Example Civil Plan)
Tire Dunker Water
Disposal Practices
Inspections indicate tire dunker water is
commonly discharged to stormwater
Staff are often unaware of proper disposal
requirements
The Dept. of Ecology considers this a
“processed wastewater”
According to the WA State Industrial
Stormwater General Permit (ISGP)
The Permittee must not allow this process
wastewater to discharge to ground, comingle with
stormwater, or enter storm drains; and must collect in
a tank for off-site disposal, or discharge it to a
sanitary sewer, with written approval from the local
sewage authority.” – (S3.B.4.i.7)
Violations
Identified
Illicit discharge of tire dunker water that may
contain oils, metals, and other pollutants like
6PPD
Illicit discharge of tire wash water containing
soap
In this case, an illicit connection to the storm
drains was identified in the dye testing
investigation
Infrequent storm drainage system maintenance
and cleaning
which allows pollutants and sediment to build
up and increases the risk of contaminated
runoff leaving the site and entering surface
waters
Required Corrective
Actions
Inspect and clean the storm drainage
system to address excessive sediment
buildup
Eliminate discharge of tire dunker process
wastewater to the storm drainage system
Eliminate discharge of tire wash water and
soaps to the storm drainage system
Eliminate the illicit discharge by properly
rerouting the two covertly connected drains to
the sanitary sewer system
Install an oil/water separator for appropriate
pretreatment
7
Key Inspection Focus Areas
Key points for effective evaluations
Structural & Operational
Practice
Inform businesses that
discharging tire dunker
water is prohibited.
Correct the illicit connection
by connecting it to the local
sewer or paying for off-site
disposal.
Treatment Systems
The presence and
condition of oil/water
separators are critical;
they must be regularly
maintained and functional
for effective pretreatment.
Employee Training
Providing and
disseminating proper
disposal guidance and
BMPs to staff is key to
protecting stormwater.
8
Next Steps
Ensuring Compliance and Protecting Water
To protect water quality, it is essential to implement thorough inspections, fostering
education and technical support to achieve compliance with regulations, and promote
environmental stewardship within local businesses.
Send a Formal Letter
Inspection report
Cite code violations
Outline required action items
Timeline to complete
Next steps to come into compliance
Follow-up inspection to ensure
compliance
Coordinate with Applicable Internal Departments
Verify if permitting will be needed
Connect the business w/applicable
permitting department staff
Ensure clear understanding (processed
wastewater must not go into storm drains)
Follow-up
Inspection
The coalescing plate separator was cleaned
Three CBs still had significant sediment,
indicating they were not cleaned
Contacting and communicating with the
contractor hired took several days
The company did come back to clean the
remaining three CBs that were missed
Follow-up
Inspection
An illicit discharge was observed on-site
No cleanup efforts had been made by staff
Assistant Manager was informed that cleanup
is required
A follow-up letter outlining the violation and
corrective action required was sent to the
business
Ensuring compliance protects our
environment
Questions and
Discussion