Fact Sheet
Reducing Zinc in Industrial
Stormwater
Background
DEQ administers stormwater permits that set
conditions for how Oregon businesses must
manage stormwater and surface runoff in order
to reduce pollution and protect the environment.
These permits are officially called National
Pollutant Discharge Elimination System
Industrial Stormwater General Permits No. 1200COLS and 1200-Z. These permits regulate the
discharge of stormwater to surface waters from
certain categories (types) of industries by
establishing benchmarks, goals and identifying
best practices to better protect Oregon’s waters.
This document provides guidance for businesses
evaluating zinc in their stormwater discharge.
DEQ does not endorse a specific form of
pollution control or treatment. Oregon businesses
can choose the option that works best to meet the
conditions of the stormwater permit.
Too much zinc is harmful
Zinc from stormwater runoff is harmful to fish
and other aquatic life. In marine waters, aquatic
species suffer acute effects from zinc at
concentrations as low as 90 μg/L. In freshwater,
this concentration can be as low as 5.6 μg/L for
salmon. Adverse effects of zinc include altered
behavior, altered blood and serum chemistry,
impaired reproduction, and reduced growth.
Sources of zinc in stormwater discharge
from industrial facilities
The most common sources of zinc found at
industrial facilities include the following:
 Galvanized metal surfaces
 Roof gutters and downspouts
 Motor oil
 Hydraulic fluid
 Tire wear and brake pad dust
 Chain link fences
 Galvanized steel storm pipes
Other less common and often overlooked sources
of zinc include:
 Moss control chemicals
 Some fertilizers and pesticides
 Some white paints
 Some wood preservatives
How to reduce zinc in stormwater
discharge
There are several options for reducing zinc in an
industrial facility’s stormwater discharge. These
include:
 BMPs (best management practices),
including source control (i.e., eliminating or
reducing the sources of zinc)
 Treatment of stormwater (treating and
removing zinc in stormwater runoff)

LIDs (low impact developments)
Probably the most effective option is source
control; this method involves eliminating sources
of zinc and preventing contact with precipitation
or stormwater runoff. Some examples of source
control are painting galvanized surfaces with
enamel or zinc-abatement paints, sweeping
surfaces to remove zinc-enriched dust and debris,
or relocating or covering sources of zinc to
prevent contact with precipitation or stormwater
runoff.
The zinc benchmark of a concentration less than 0.12
mg/L is considered protective to our marine and
freshwater aquatic life. (Photo courtesy of Oregon
Live)
Stormwater Program
811 SW 6th Avenue
Portland, OR 97204
Phone: (503) 229-5696
(800) 452-4011
Fax:
(503) 229-5850
Contact: Erich Brandstetter
www.oregon.gov/DEQ
Eastern Region
475 NE Bellevue
Suite 110
Bend, OR 97701
Phone: (541) 388-6146
(866) 863-6668
Fax:
(541) 388-8283
Contact: Krista Ratliff
www.oregon.gov/DEQ
Northwest Region
2020 SW 4th Avenue,
Suite 400
Portland, OR 97201
Phone: (503) 229-5263
Fax:
(503) 229-6945
Contact: Jennifer Weaver
www.oregon.gov/DEQ
Western Region
165 E. 7th Avenue,
Suite 100
Eugene, OR 97401
Phone: (541)686-7838
(800)844-8467
Fax:
(541)686-7551
Contact: Mark Riedel
www.oregon.gov/DEQ
City of Portland
Bureau of Environmental
Services
6543 N. Burlington Ave.
Portland, OR 97203-5452
Phone: (503) 823-5320
Contact: Michael Pronold
Clean Water Services
2550 SW Hillsboro
Highway
Hillsboro, OR 97123
Phone: (503) 681-5129
Contact: Clayton Brown
City of Eugene
410 River Avenue
Eugene, OR 97404
Phone: (541) 682-8616
Contact: Jonathan Wilson
Once zinc comes into contact with precipitation
and mixes with stormwater runoff, a facility will
need to determine the best way to treat the
runoff. Selecting a treatment method or BMP to
reduce zinc levels in stormwater can be difficult
and costly. When determining how to reduce
zinc in stormwater it is important to:
 Assess the sources of zinc
 Collect good samples and follow protocols
to maintain quality data (from both the
source and the entire site)
 Evaluate the current site conditions and
BMPs already in place to determine if
improvements can be made
Each business is unique and there is no single
solution to eliminating zinc in a facility’s
stormwater discharge. It may be advisable to hire
a consultant or qualified professional who has
knowledge of the available treatment systems
and their effectiveness.
Generally the most BMPs are sweeping paved
surfaces and painting, coating or encapsulating
galvanized surfaces.
How to reduce zinc in stormwater runoff
from galvanized metal structures:
In many cases the source of zinc in the
stormwater discharge is from a galvanized metal
roof and downspout system. Covering industrial
activities certainly prevents stormwater from
coming into contact with potentially more
harmful chemicals, but a galvanized metal roof
may cause an unwanted increase in the zinc
concentration in stormwater discharge.
Galvanized metal roofs are often used to cover
industrial activity areas. (Photo courtesy of Google)
Source Control BMPs: Paint galvanized metal
roofs with enamel or zinc-abatement paint or
encapsulate the metal roof with a single
membrane roofing system. In addition, avoid the
use of galvanizing sheeting in new construction
projects.
Other BMPs: Clean sediment and debris from
gutters and downspouts that may contain zinc,
and maintain the coating of a sealed metal roof.
Treatment: Install a roof downspout filtration
system. There are several options that a facility
can choose, ranging from do-it-yourself projects
to treatment systems costing several thousands of
dollars. Low-cost rain barrels can be effective
and many use organic materials to remove zinc
from stormwater. Several vendors offer
downspout filtration systems and systems that
treat the stormwater discharge from the entire
facility. These products are designed specifically
to reduce zinc from galvanized metal roofs or
other specific pollutants.
LIDs: Reroute stormwater runoff from metal
roofs and downspouts to an area on the property
where the stormwater can filter through a
vegetated surface and/or into a stormwater
biofiltration swale that encourages the infiltration
of stormwater into the ground. Stormwater
bioswales, rain gardens, infiltration, and
detention basins are a few examples of LIDs that
may reduce zinc concentrations in a facility’s
stormwater discharge.
How to reduce zinc from motor oil and
hydraulic fluids in stormwater runoff:
Zinc is a common chemical used in both motor
oil and hydraulic fluid. During periods of little or
no precipitation, motor oil and hydraulic fluid
can buildup on paved surfaces. This build-up can
also occur in the dust and debris that absorbs
these fluids. Parking areas, loading docks, and
equipment storage areas may be sources of
leaked fluid contributing to an increase in zinc in
stormwater discharge.
Better housekeeping and employee education can be
utilized to avoid motor oil from coming into contact
with stormwater runoff.
Source Control BMPs: Sweep parking areas,
loading docks, and other paved surfaces to
minimize the amount of zinc from motor oil and
hydraulic fluid entering stormwater runoff.
Sweeping removes large and small particles and
with them, motor oil, hydraulic fluid, and tire
dust. Sweeping may also remove zinc that is
deposited on the paved surfaces (and the
associated dust and debris) from galvanized
metal surfaces.
Last updated: 12/16/14
By: Mark Riedel
Other BMPs: Develop a sweeping maintenance
and housekeeping program. Vacuum-assisted dry
sweepers are very effective at removing solids
and fine dust that contains zinc.
Treatment: Install a catch basin treatment
system with oil-absorbent material to remove
oils from stormwater runoff. Vendors offer
filtration and cartridge systems that are designed
specifically to target the removal of zinc and oils
from stormwater discharge.
LIDs: Reroute stormwater runoff from paved
areas and loading docks to an area on the facility
where the stormwater can filter through a
vegetated surface and/or into a stormwater
biofiltration swale that encourages the infiltration
of stormwater into the ground. Stormwater
bioswales, rain gardens, infiltration, and
detention basins are a few examples of LIDs that
may reduce zinc concentrations in a facility’s
stormwater discharge.
How to reduce zinc in stormwater from
enriched dust and debris:
Zinc is utilized in the manufacturing of both tires
and brake pads. As vehicles and equipment
travel around a facility, tire wear is increased in
areas that require tight turning, and in areas of
acceleration and deceleration (e.g., frequent
braking). Dust released from these processes can
be deposited on the ground and nearby surfaces.
Removal of this dust may also help lower the
zinc in the stormwater discharge.
Zinc-enriched dust and debris can be reduced by
utilizing the same methods described in the
motor oil and hydraulic fluid section.
Additional resources
There are several websites available to assist in
performing a self-evaluation of zinc sources. An
internet search for the term “reducing zinc in
stormwater” should bring up several listings.
DEQ has prepared an Industrial Stormwater Best
Management Practices Manual that discusses
zinc and several other pollutant sources and
identifies actions you can take to reduce
pollution in stormwater.
The State of Washington has posted videos on
their Washington Stormwater Channel. Videos
include BMPs to reduce zinc and other pollutants
in stormwater.
Another resource may be Oregon State
University Extension Service. You can check
their website for the availability of classes and
information that address reducing impact from
stormwater discharge.
To speak with someone about reducing pollution
in stormwater please contact the DEQ
regional office in your area.
Alternative Formats
Alternative formats of this document can be
made available. Contact DEQ’s Office of
Communications & Outreach for more
information at (503) 229-5696.
Hearing impaired, dial 711.