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Washington State Pesticide Permit Conditions

Washington State Pesticide Permit Conditions

Conditions Necessary to Meet State Standards for the EPA

Pesticides General Permit (PGP)

Washington State Department of Ecology (Ecology) is conditionally certifying the PGP issued 

October 31, 2011 by EPA. Ecology’s conditions are below.

Condition 1. REQUIREMENTS FOR PESTICIDE APPLICATORS

Permittees must be licensed in the State of Washington to apply pesticides and must comply with 

chapters 16-228 of the Washington Administrative Code (WAC) , 15.58 Revised Code of 

Washington (RCW), and 17.21 RCW.

Condition 2. REQUIREMENTS FOR PESTICIDE APPLICATION

A. Permittees may only use pesticide products that are FIFRA- labeled and must comply 

with the products’ FIFRA label. Permit requirements do not reduce the requirements on 

the FIFRA label. The pesticide product must be labeled for the Permittee’s intended use.

B. The application of pesticide products must not cause or contribute to violations of the 

Water Quality Standards for Surface Water of the State of Washington (chapter 173-

201A WAC), Ground Water Quality Standards (chapter 173- 200 WAC), Sediment 

Management Standards (chapter 173-204 WAC), and human health-based criteria in the 

National Toxics Rule (40 CFR 131.36). Discharges that do not comply with these 

standards are prohibited.

Citations:

• Chapter 90.48 RCW

• RCW 90.48.010

• Chapter 173-201A WAC

• Chapter 173-226 WAC

• 173-226-070 WAC

Condition 3. ALLOWED ACTIVE INGREDIENTS AND CONDITIONS FOR USE

Restrictions on the active ingredients allowed, when, and how pesticide products may be applied 

(Conditions 4-11) are technology-based requirements Ecology has determined to meet AKART

for the control of pollution. AKART requirements protect the existing beneficial uses of waters 

of the state listed in chapter 173-201A WAC.
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Washington State Pesticide Permit Conditions

The Permittee must avoid treatments that restrict public water use during the opening week of 

fishing season, Memorial Day weekend, Independence Day weekend, and Labor Day weekend 

and must minimize treatments that restrict public water use during weekends.

Citations:

• Chapter 90.48 RCW

• RCW 90.48.010

• Chapter 173-201A WAC

• WAC 173-201A-020

• WAC 173-201A-300

• WAC 173-201A-410(4)(c)(i and ii)

• Chapter 173-226 WAC

• WAC 173-226-070

• WAC 173-226-090

Condition 4. AQUATIC MOSQUITO CONTROL

A. ALLOWED ACTIVE INGREDIENTS

1. Bacillus sphaericus (strain H-5a5b)

2. Bacillus thuringiensis israelensis (Bti)

3. Malathion

4. Methoprene

5. Monomolecular surface films

6. Paraffinic white mineral oil

7. Spinosad

8. Temephos

9. Etofenprox

10. Malathion

11. Naled

12. Natural Pyrethrins

13. Permethrin

14. Piperonyl Butoxide (PBO)

15. Prallethrin

16. Resmethrin

17. Sumithrin (d-phenothrin)

B. ADDITIONAL RESTRICTIONS

1. The Permittee may apply larvicides provided one or more of the following conditions

are met.
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Washington State Pesticide Permit Conditions

a. Pretreatment surveillance of a potential larvicide application site indicates that at

least one larvae/pupae is present in at least one of three dips. In the event that the 

Permittee finds larvae/pupae, and the area is treated, the Permittee may continue

pre-emptive larvicide treatments without dipping for the remainder of the

treatment season.

b. Methoprene may be used as a pre-emergent dry-land treatment on intermittently 

flooded areas that have a record of mosquito hatches following flooding.

c. The application site is in, or adjacent to a county in which mosquito, bird, animal,

or human mosquito-borne disease cases are confirmed during the current

treatment season.

d. The treatment site is a catch basin, storm drain, and utility or transportation vault.

2. Permittees may only use paraffinic white mineral oil or malathion as larvicides if

other pesticides are ineffective at a specific treatment site and the water body is nonfish bearing. To determine if the water body is fish bearing, consult with Washington 

State Department of Fish and Wildlife (WDFW). Contact information for WDFW 

Regional Wildlife Biologists may be accessed at http://wdfw.wa.gov/about/contact/.

3. The Permittee may not apply temephos in lakes, streams, in the littoral zone of water

bodies, or on sites listed in Condition 4.B.4. The use of temephos is allowed only in 

response to the development of pesticide resistance within a specific larval mosquito 

population.

4. Due to the present of sensitive, threatened, candidate, or endangered species only 

Bacillus thuringiensis israelensis (Bti) and Bacillus sphaericus (strain H-5a5b) may be 

used in the following areas:

a. Grant County, north of Moses Lake, within the Crab Creek watershed: T21N 

R27E Sections 1 and 12; T21N R28E Sections 7, 17, 18, 19, 28, 29, 30, 31, 32, 

and 33.

b. Grant County, south and west of Moses Lake and south of Interstate-90, the 

northern portion of the Potholes: T19N R27E Sections 33, 34, and 35; T19N 

R28E Sections 29, 30, 31 and 32; T18N R27E Sections 1, 2, 3, 4, 8, 9, 10, 11, 12, 

13, 14, 15, 16, and 17; T18N R28E Sections 5, 6, 7, 8, 17, and 18.

c. Grant County, area within and near the Sun Lakes – Dry Falls State Park 

wetlands: T24NR27E and 28E.

d. Kitsap County: lakes, ponds, and wetlands located in T22N R1W Sections 1, 2, 

10, 11, and 12.
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Washington State Pesticide Permit Conditions

e. Skamania County, east of Carson, all waters in T3N R8E Sections 23, 24, 25, 26, 

and 36; T3NR9E Sections 30 and 31.

f. Thurston County, west of Yelm: lakes, ponds, and wetlands located in T17N R1E 

Sections 8, 9, and 21.

g. Thurston County, T16N R4W Sections 31, 32, and 33.

Condition 5. AQUATIC PLANT AND ALGAE MANAGEMENT 

A. This section applies to products applied to the eradication of noxious and WSDA 

quarantine list weeds and the control nuisance and noxious weeds in lakes, rivers, 

streams, other standing and flowing waterbodies (not including irrigation canals), 

emergent vegetation around waterbodies, and roadside and ditch banks. This does not 

cover activities in saltwater areas.

B. Noxious Weed Eradication

Eradication projects target only state-listed noxious weeds or plants listed on the WSDA 

quarantine-list. The goal is the complete and permanent removal of these species from the

entire water body. As such, littoral zone limitations do not apply to eradication of noxious 

weeds or weeds on the quarantine list. Impacts to non-target plants are acceptable to the 

extent needed to eradicate the target plants. Eradication is allowed only for:

1. All noxious weeds as identified in chapter 16-750 WAC.

2. Plants listed on the quarantine list as identified in chapter 16-752 WAC.

3. Non-native and potentially invasive plants not listed on the above lists, as determined 

by the WSNWCB, WSDA, or Ecology.

C. Nuisance and Noxious Weed Control

The goal is to maintain native aquatic vegetation for habitat while allowing partial plant 

removal for recreation and other beneficial uses. Permit requirements differ depending on 

plant growth forms and the legal status of the plant species in Washington. Minimal 

impact to non-target plants is acceptable to the extent needed to control the target plants.

Nuisance plants are native plants that grow in such quantity that they restrict the 

beneficial uses of a waterbody as defined in chapter 173-201A WAC.

1. Aquatic noxious weed control 

The Permittee may apply herbicides to:

a. 100 percent of noxious weeds if they are Class A weeds, Class B weeds in areas 

where they are designated for control, as identified in chapter 16-750 WAC, and 

Class C weeds where they are selected for control by a county Noxious Weed 

Control Board (RCW 17.10.080).

b. 100 percent of any submersed noxious or quarantine-list weeds not covered under 

(a) if the Permittee conducts weed control using a selective herbicide.
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Washington State Pesticide Permit Conditions

c. 100 percent of any emergent or floating-leaved noxious weeds and quarantine 

listed weeds.

2. Aquatic nuisance plant control

The Permittee may apply chemicals to:

a. No more than 25 feet on either side of a dock or no more than an area 50 feet 

wide per lot for individual treatments targeting submersed and floating-leaved 

plants. Treatment of the vegetated area may extend up to 25 feet beyond the end 

of the dock. On individual lots with no docks, treatment of the vegetated area can 

extend up to 50 feet from the shore.

b. No more than 40 percent of emergent shoreline plants such as cattails and bulrush 

on individual lots for individual treatments.

c. A percentage of a water body’s littoral zone based on the littoral acres of the 

water body and the size of the water body.

i. The geographic area where the Permittee applies chemicals must remain 

the same for the entire length of the permit coverage up to the maximum 

percentage of the littoral zone allowed for by water body size.

ii. All untreated littoral areas must include native vegetation from the shore to 

the edge of the littoral zone where the plants stop growing in deeper water.

iii. The cumulative percentage of the littoral zone where herbicides may be 

applied must not exceed the amount allowed below:

1) In water bodies up to 15 acres in size, the Permittee may apply 

herbicides to no more than 75 percent of the littoral zone.

2) In water bodies over 15 acres and up to 50 acres in size, the Permittee 

may apply herbicides to no more than 60 percent of the littoral zone.

3) In water bodies over 50 acres and up to 500 acres in size, the Permittee 

may apply herbicides to no more than 50 percent of the littoral zone.

4) In water bodies over 500 acres in size, the Permittee may apply 

herbicides to no more than 30 percent of the littoral zone.

3. Roadside and ditch bank plant control

a. For activities conducted by state and local agencies, the Permittee may apply 

herbicides to 100 percent of the plants within the right of way.

b. The Permittee may apply herbicides to no more than 40 percent of native 

vegetation of roadsides and ditches on privately owned individual lots, but may 

apply herbicide to 100 percent of any noxious or quarantine-listed weeds.

4. Algae control.

The Permittee may apply algaecides to the entire water body or sections of the water 

body, as needed, when cyanobacteria or other potentially toxic or environmentally 

harmful algae species are expected to form blooms in the water body.

The Permittee may apply algaecides to filamentous algae so long as the treated areas 

do not exceed the maximum amount of littoral zone allowed for treatment in 
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Washington State Pesticide Permit Conditions

Condition 5.C.2.c.iii. Different littoral zone limitations apply to the herbicide 

fluridone. See Treatment Limitations in Table 1.

5. Nutrient Inactivation

The Permittee may apply approved buffering agents and alum and calcium 

hydroxide/oxide and calcium carbonate as phosphorus inactivation products to the 

entire water body or sections of the water body per permit sections Table 2.

D. ALLOWED ACTIVE INGREDIENTS

1. 2,4-D, Amine Formulation

2. 2,4-D, Ester Formulation

3. Diquat Dibromide

4. Endothall, Dipotassium salt (e.g. Aquathol)

5. Endothall, Monopotassium salt (e.g. Hydrothol)

6. Fluridone

7. Glyphosate

8. Imazamox

9. Imazapyr

10. Sodium carbonate peroxyhydrate

11. Triclopyr TEA 

12. Adjuvants: Agri-DexTM, BondTM, Bronc MaxTM, Bronc Plus Dry-EDTTM, Class Act 

NGTM, CompetitorTM, Cut-RateTM, Cygnet PlusTM, Dyne-AmicTM, ExciterTM, Fast 

BreakTM, FractionTM, IntensifyTM, InterlockTM, KineticTM, Level 7TM, LI-700TM, 

LiberateTM, MagnifyTM, One-Ap XLTM, Pro AMS Plus Activator PenetrantTM, 

SinkerTM, Spray-RiteTM, TacticTM, TronicTM

13. Nutrient Inactivation Products: aluminum sulfate, sodium aluminate, calcium 

hydroxide/oxide, and calcium carbonate. See Table 2 for specific restrictions on 

nutrient inactivation products.

14. Marker dyes, shading and water clarification products. See Table 3 for specific 

restrictions on these products.

E. ADDITIONAL RESTRICTIONS

1. Identified Wetlands

The Permittee may only treat high use areas to provide for safe recreation and boating 

in identified and/or emergent wetlands. Treated area must be limited to protect native 

vegetation. For eradication projects, the Permittee must make every effort to protect 

native wetland vegetation while removing noxious species.

2. The Permittee must use Washington Department of Natural Resources (WDNR)

Natural Heritage Program database to determine if sensitive, threatened, or 

endangered (rare) plants are present in the proposed treatment area. If a rare plant 

does occur in or around the waterbody, the Permittee must survey for the rare plant 
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Washington State Pesticide Permit Conditions

and mitigate for impacts to it. The rare plant database is currently located at 

http://www1.dnr.wa.gov/nhp/refdesk/plants.html.

3. The Application of Products

a. The Permittee must comply with the specific restrictions/limitations on the use of 

each chemical listed in Tables 1 – 3 below.

b. When there are potable water restrictions on the product label, the Permittee must 

not apply any chemical until it has notified people who withdraw drinking water 

from the water body. If requested by the affected water user(s), the Permittee 

must provide an alternative drinking water supply until the intake water tests at or 

below the concentration specified for that chemical in Table 1, or until the period

specified in Table 1 for that chemical has elapsed. If there is no drinking water 

restriction listed in Table 1, the Permittee must follow all label conditions for 

potable water supply. If requested by a water user, the Permittee must provide 

advance notice of pending treatments on a time schedule agreed to by all parties.

c. If the treatment affects potable water use on water bodies with municipal or 

community drinking water intakes, the Permittee must obtain written consent to 

the treatment from the municipality or community. The Permittee must keep this 

consent letter for 5 years.

d. People withdrawing water under a legal water right or claim for irrigation or 

livestock watering purposes may request an alternate water supply during the 

treatment if the label has restrictions for those uses. The Permittee must provide 

an alternative water supply until the intake water tests at or below the irrigation 

restriction concentration or livestock drinking water concentration on the product 

label or until the time interval specified on the label has elapsed. If requested by a 

water user, the Permittee must provide advance notice of pending treatments on a 

time schedule agreed to by all parties.

e. The Permittee must follow WDFW’s Fish and Wildlife Treatment Windows for 

Ecology’s Aquatic Plant and Algae Management Permit (Treatment Windows) to 

protect salmon, steelhead, and bull trout populations and other sensitive species 

and habitats. WDFW may periodically update the Treatment Windows as new 

information becomes available see: 

http://www.ecy.wa.gov/programs/wq/pesticides/final_pesticide_permits/aquatic_p

lants/permitdocs/wdfwtiming.pdf. If a waterbody is not listed in the Treatment 

Windows, the default window is July 15 – October 31, both dates inclusive. 

Contact the regional WDFW biologist to develop a new timing window if the 

default window will not provide for adequate treatment.

f. The Permittee must follow the specific restrictions and advisories identified in 

Tables 1 – 3 below. Recreational restrictions/advisories apply to swimming, 

boating, water skiing, etc. Swimming restrictions/advisories apply to primary 
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Washington State Pesticide Permit Conditions

contact activities such as swimming, wading, and water skiing. Drinking water 

restrictions apply to residents drinking lake water as their sole source of potable 

water or where they hold a water right for potable water.

F. MONITORING REQUIREMENTS

1. Application of Herbicides and Algaecides

a. The Permittee must monitor dissolved oxygen levels pre- and post-treatment 

when contact herbicides are used in water bodies on the 303(d)-list for dissolved 

oxygen. Immediately before treating, the Permittee must monitor surface and 

bottom dissolved oxygen concentrations at a sampling location in the center and 

at the edge of the proposed treatment area(s).

b. The Permittee must select at least one representative treatment area to monitor 

each time the water body is treated. The Permittee must monitor post-treatment 

surface and bottom dissolved oxygen concentrations no earlier than seven days 

and no later than 14 days after the treatment, at the same time of day that the pretreatment monitoring occurred and at the same sites and depths. The Permittee 

must keep the data for 5 years and make it available upon request.

2. Application of Phosphorus Inactivation Products 

a. Aluminum sulfate or sodium aluminate (alum)

For whole or partial lake treatments, the Permittee must measure, at a minimum, 

surface water pH once in the morning prior to any alum addition and once in the 

afternoon one hour after alum addition has stopped for that day. The Permittee 

must continue this monitoring regime for the duration of the treatment and for 24 

hours following treatment completion. The monitoring location must be 

representative of water body-wide conditions. If the pH decreases to less than 

6.2, the Permittee must stop treatment, analyze for alkalinity, and must take 

immediate steps to increase the pH.

b. Calcium hydroxide/oxide or calcium carbonate treatment

The Permittee must measure pH once on the day before treatment, and once in the 

morning and once in the afternoon for the duration of the treatment and for 24 

hours following treatment. If the pH is above 9.0 due to the effects of the 

treatment (rather than through photosynthesis), the Permittee must stop treatment.

c. Continuous Injection Systems

The Permittee must measure pH at a minimum once every two weeks during the 

first month of continuous injection and thereafter once a month for the duration of 

the injection process. The Permittee must ensure that pH measurements represent 
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Washington State Pesticide Permit Conditions

water body-wide conditions, unless the injection system is in an isolated area in 

relation to the main water body (e.g., in a bay with a narrow channel to the main 

water body). For isolated areas of water bodies, the Permittee must measure pH 

at the end of the bay and in the main water body.
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Washington State Pesticide Permit Conditions

Table 1: Specific Restrictions on the Application of Herbicides and Algaecides for Control and Eradication Projects

Active Ingredient Subject to Timing Restrictions/

Advisories

Treatment 

Limitations Other Specific Restrictions

2, 4 – D (amine) Yes for salmon, 

steelhead, bull trout –

check timing table for 

other priority species

Swimming advisory 

during treatment, and 

for 24-hours posttreatment (in the 

treated area) 

Control projects 

only: Do not apply 

within 400 feet of an 

outlet stream if there 

is an outflow. 

Ensure that residents drinking lake 

water turn off their intakes and do 

not resume drinking treated water 

for 28 days following application. 

As an alternative to waiting, treated 

water may be used for drinking 

once the 2,4-D level in the intake 

water is determined to be 0.07 

mg/L or less, or the applicator 

complied with label setback 

distances.

2, 4 – D (ester) See other specific 

restrictions – Yes for 

salmon, steelhead, bull 

trout – check timing 

table for other priority 

species

Swimming restriction 

during treatment, and 

for 24-hours posttreatment (in the 

treated area) 

None Do not use in salmon-bearing 

waters.

Diquat Yes for salmon, 

steelhead, bull trout –

check timing table for 

other priority species

Swimming advisory 

during treatment, and 

for 24-hours posttreatment (in the 

treated area) 

• Do not spray on 

emergent 

shoreline 

vegetation(e.g. 

cattails, bulrush)

or algae.

• Do not pour 

Diquat directly 

from container.

Ensure that residents drinking lake 

water turn off their intakes and do 

not resume drinking treated water 

for 10 days following application. 

As an alternative to waiting, treated 

water may be used for drinking 

once the Diquat level in the intake 

water is determined to be 0.02 

mg/L or less.
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Washington State Pesticide Permit Conditions

Endothall 

Dipotassium 

salt 

(AquatholTM)

Yes for salmon, 

steelhead, bull 

trout – check 

timing table for 

other priority 

species

Swimming advisory 

during treatment, 

and for 24-hours 

post-treatment (in 

the treated area) 

Control projects only: Do 

not apply within 400 ft of an 

outlet stream if there is an 

outflow. 

Ensure that residents drinking lake 

water turn off their intakes and do 

not resume drinking treated water 

for 28 days following application. 

As an alternative to waiting, 

treated water may be used for 

drinking once the endothall level 

in the intake water is determined 

to be 0.10 mg/L or less.

Endothall

Monopotassium 

salt (Hydrothol 

191TM)

Yes for salmon, 

steelhead, bull 

trout – check 

timing table for 

other priority 

species

Swimming advisory 

during treatment, 

and for 24-hours 

post-treatment (in 

the treated area)

• Use for control of 

filamentous algae, 

cyanobacteria, or harmful 

algae only. See Condition 

5.C.4

• Limit concentrations to 

0.2-mg/L of active 

ingredient 

• Treatment must occur from the 

shoreline outward into the 

water body.

• Ensure that residents drinking 

lake water turn off their intakes 

and do not resume drinking 

treated water for 14 days 

following application. As an 

alternative to waiting, treated 

water may be used for drinking 

once the endothall level in the 

intake water is determined to 

be 0.1 mg/L or less. 

Fluridone No for fish, but 

check timing 

table for other 

sensitive species. 

None Unless operating under a plan 

to eradicate a noxious weed, 

fluridone application is 

further limited to no more 

than 50 percent of the littoral 

zone in lakes up to 50 acres 

and no more than 40 percent 

of the littoral zone in lakes 

from 50 - 500 acres. 

None 

Glyphosate No for fish, but None None None
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Washington State Pesticide Permit Conditions

check timing 

table for other 

sensitive species.

Sodium 

carbonate 

peroxyhydrate 

No for fish, but 

check timing 

table for other 

sensitive species. 

Swimming advisory 

during treatment, 

and for 2-hours posttreatment (in the 

treated area 

Do not treat plants growing 

on the shore. 

None 

Imazapyr No for fish, but 

check timing 

table for other 

sensitive species. 

None None None 

Imazamox No for fish, but 

check timing 

table for other 

sensitive species. 

None None None 

Triclopyr TEA No for fish -

check timing 

table for other 

priority species. 

Swimming advisory 

during treatment, 

and for 12-hours 

post-treatment (in 

the treated area) 

Aerial applications are not 

allowed. 

Ensure that residents drinking lake 

water turn off their intakes and do 

not resume drinking treated water 

for 28 days following application. 

As an alternative to waiting, 

treated water may be used for 

drinking once the triclopyr level in 

the intake water is determined to 

be 0.4 mg/L or less, or the 

applicator complied with label 

setback distances. 
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Washington State Pesticide Permit Conditions

Table 2 – Nutrient Inactivation Products

Product Subject to Timing Restrictions/ 

Advisories Treatment Limitations Other Specific Restrictions 

Alum • No for fish - check 

timing table for 

sensitive species. 

• Timing should address 

aquatic plant biomass 

that may interfere with 

inactivation of 

sediment phosphorus 

(requiring early spring 

or fall treatment). 

None • Application must cease 

when wind speed is 

greater than 15 miles per 

hour 

• Powdered alum must be 

mixed with water to form 

a slurry before applying to 

the water surface. 

• The pH of lake water 

during treatment must 

remain between 6.0 and 

8.5 based on lake average. 

• Only aluminum 

compounds suitable for 

water treatment may be 

used. 

• Buffering materials must 

be available for use. 

• A jar test must be completed prior to 

whole lake treatments only if a buffer 

other than sodium aluminate is used 

or a ratio of liquid alum to liquid 

sodium aluminate differs from 2:1 by 

volume. 

• An on-site storage facility is required 

for any treatment requiring 9,000 

gallons of alum or more, or the 

project proponent must have a plan to 

store any unused alum or buffering 

products. 

• Follow the monitoring requirements 

in Condition 5.F.2. 

Calcium No for fish - check timing 

table for sensitive species. 

None The pH must remain between 

6.0 and 9.0. 

• A jar test must be completed prior to 

treatment to identify proper dosing 

levels. This jar test needs to be 

conducted at least over a 24-hour 

period to ensure that the pH response 

is at equilibrium with water 

chemistry. 

• Follow the monitoring requirements 

in Condition 5.F.2.
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Washington State Pesticide Permit Conditions

Note: The products Nutrient Inactivation products listed above are not registered as pesticides through FIFRA or regulated under any 

other federal laws or regulations. A licensed applicator is not needed for the application of any of these products to waters of the 

United States.

Table 3: Biological Water Clarifiers, Shading Products

Product Restrictions 

Shading products Do not apply directly to rivers or streams or any lake that 

discharges to other surface waters of the state. 

Biological Water Clarifiers Use only in water bodies with no discharge to other surface 

waters of the state during and for two weeks after treatment. 

Note: These restrictions are in addition to the federal FIFRA label requirements (when applicable).
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Washington State Pesticide Permit Conditions

Condition 6. AQUATIC NOXIOUS WEED CONTROL

A. This section applies to products applied to control emergent Washington state noxious 

and quarantine list weeds in the riparian areas around waterbodies, including salt water. 

This section does not apply to the in-water application of products to control aquatic plants. 

For in-water use, refer to Condition 5.

Plants authorized for treatment include: 

1. Noxious weeds as identified in chapter 16-750 WAC. 

2. Plants listed on the WSDA quarantine list as identified in chapter 16-752 WAC. 

3. Non-native and potentially invasive plants not listed on the above lists, as determined by 

the WSNWCB, WSDA, the Washington Invasive Species Council (WISC), or Ecology.

B. ALLOWED ACTIVE INGREDIENTS

1. Bispyribac-sodium

2. Carfentrazone-ethyl

3. 2,4-D, Amine Formulation

4. Flumioxazin

5. Glyphosate

6. Imazamox

7. Imazapyr

8. Penoxsulam

9. Triclopyr TEA

10. Adjuvants: Agri-DexTM, BondTM, Bronc MaxTM, Bronc Plus Dry-EDTTM, Class Act 

NGTM, CompetitorTM, Cut-RateTM, Cygnet PlusTM, DestinyTM, Dyne-AmicTM, 

ExciterTM, Fast BreakTM, FractionTM, InterlockTM, KineticTM, Level 7TM, LI-700TM, 

LiberateTM, MagnifyTM, One-Ap XLTM, Pro AMS Plus Activator PenetrantTM, 

SinkerTM, Spray-RiteTM, Superb HCTM, TacticTM, TronicTM

11. Marker Dyes

C. ADDITIONAL RESTRICTIONS

Permittees shall make herbicide applications only for the control of state listed noxious 

weeds and weeds on the WSDA quarantine list that are found in aquatic environments. 

Noxious weed means those species of plants listed as Noxious class A, B, and C weeds 

by the Washington State Noxious Weed Control Board in accordance with 17.10 RCW. 

WSDA maintains the quarantine list in accordance with 17.24 RCW.

Condition 7. IRRIGATION SYSTEM AQUATIC WEED CONTROL

A. ALLOWED ACTIVE INGREDIENTS

1. Copper (dissolved)
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Washington State Pesticide Permit Conditions

2. Acrolein

3. Endothall, Dipotassium salt (e.g. Aquathol)

4. Endothall, Monopotassium salt (e.g. Hydrothol)

5. Xylene

6. Sodium Carbonate Peroxyhydrate

7. Fluridone

8. Imazapyr

B. ADDITIONAL RESTRICTIONS

1. Point of Compliance 

a. The point of compliance means the location where water treated with pesticides 

enters a surface water body.

b. For Amon Wasteway, Snipes Creek Wasteway, Sulphur Creek Wasteway, and 

Crab Creek, the point of compliance shall be at or above the following locations:

i. Amon Wasteway where it exits the golf course at Gage Road 

(approximately latitude 46.22715, longitude -119.26024).

ii. Snipes Creek Wasteway at the Benton 29.32 Lateral (near McCreadie 

Road) (approximately at latitude 46.25630, longitude -119.67406).

iii. Sulphur Creek Wasteway at Sheller Road (approximately at latitude 

46.33167, longitude -119.98021).

iv. Crab Creek at Red Rock Coulee / DCC1 wasteway (approximately at 

latitude 46.84693, longitude -119.58673).

2. Discharge Limitations

a. The discharge of any allowed active ingredient (Condition 7.A.1-8) must not 

exceed the values identified in Table 5.

Table 5: Point of Compliance Discharge Limitations

Parameter Maximum Instantaneous Concentration

Copper (dissolved) 25 ug/l 

Acrolein 21 ug/l 

Dipotassium Salt of Endothall • mg/l (acid equivalent) from March 1 to 

July 15 

• 2.5 mg/l (acid equivalent) from July 16 to 

February 29

• See Condition 7.B.6
Page | 17

Washington State Pesticide Permit Conditions

Mono Salt of Endothall • 50 ug/l (acid equivalent)

• See Condition 7.B.6

Xylene 5.1 mg/l 

Sodium Carbonate Peroxyhydrate See C7.B.3

Fluridone See C7.B.4

Imazapyr See C7.B.5

The maximum instantaneous concentration means the highest allowable discharge at any 

time.

3. For sodium carbonate peroxyhydrate applications The permittee need not conduct 

monitoring under Condition 7.C.

4. For fluridone applications:

a. The permittee shall only apply fluridone between October 1 and March 31.

b. The permittee shall only apply in-water fluridone to slow-moving or quiescent 

waters.

c. The permittee shall conduct fluridone treatments in a manner that will prevent 

treated water from reaching a point of compliance for at least eight weeks after 

application.

d. The permittee need not conduct monitoring under Condition 7.C.

5. For imazapyr applications:

a. The permittee shall only apply imazapyr between October 1 and March 31.

b. The permittee shall only apply imazapyr to slow-moving or quiescent waters.

c. The permittee shall conduct imazapyr treatments in a manner that will prevent 

treated water from reaching a point of compliance for at least two weeks after 

application.

d. The permittee need not conduct monitoring under Condition 7.C.

6. For endothall applications, The permittee must not release endothall from irrigation

canals at times that smolting salmonids are present.

C. MONITORING REQUIREMENTS

The permittee shall monitor all pesticide applications where the treated water eventually 

flows to a point of compliance according to Table 6.
Page | 18

Washington State Pesticide Permit Conditions

Table 6: Sampling Schedule

Monitoring 

Site Parameter

Method 

Detection 

Limit

Minimum 

Sampling 

Frequency

Sample 

Type

Point(s) of 

Compliance

Flow N/A Concurrent with all 

other samples

Measurement

Point(s) of 

Compliance

Copper, dissolved 5 ug/L 2 times per treatment 

See Condition 7.C.1

Grab

Point(s) of 

Compliance

Hardness (only when 

monitoring copper)

1 mg/l Concurrently with 

copper sampling

Grab

Point(s) of 

Compliance

Acrolein 2 ug/l 2 times per treatment 

See Condition 7.C.1

Grab

Point(s) of 

Compliance

Endothall 12 ug/l 2 times per treatment 

See Condition 7.C.1

Grab

Point(s) of 

Compliance

Xylene 1 mg/l 2 times per treatment 

See Condition 7.C.1

Grab

None Sodium Carbonate N/A None None

None Fluridone N/A None None

None Imazapyr N/A None None

1. The permittee shall take the two samples to identify the highest concentration of the 

pesticide. The permittee shall take both samples during the peak pesticide 

concentration at the compliance point.

a. If the travel time is 20 hours or more, the permittee shall space their sampling at 

least two hours apart.

b. If the travel time is less than 20 hours, the permittee shall space their samples at 

10% of the travel time of the pesticide.

c. If the permittee is tracking multiple treatments simultaneously, the permittee shall 

use the shortest travel time to determine if the permittee follows Condition 7.C.1.a 

or Condition 7.C.1.b.

2. If all treated water is consumed (e.g. used on-farm) and the end of the canal/spillway 

is dry, the permittee need not conduct monitoring.

3. The permittee must keep all monitoring records for a period of 5 years and make 

them available upon request.

4. In some situations, the permittee prevents treated water from reaching some points of 

compliance by closing side canals/spillways. (For example, a permittee closes a gate 

to a spillway while treating the primary canal and all the treated water passes the 

closed gate.) The permittee shall conduct full monitoring (Condition 7.C) at the points 
Page | 19

Washington State Pesticide Permit Conditions

of compliance corresponding to the closed canals/spillways when the canals/spillways 

are reopened unless the closed canal/spillway is kept closed for double the travel time 

it takes the treated water to reach the point of closure. In this situation, no monitoring 

is required. For this special situation only, the travel time is counted from when the 

pesticide application ends. (For example, if a treatment ends at 1:00 and it takes four 

hours to pass the closed gate at 5:00, the permittee shall keep the gate closed for 

another four hours until 9:00 for this special situation to apply).

5. Time Travel Study

a. The permittee shall support all monitoring by completing a time travel study at 

each application site.

b. Time travel studies shall determine the amount of time it takes the pesticide to 

travel from the application site to the point of compliance.

c. The flow conditions during the time travel study shall mimic the conditions 

during pesticide application.

d. The permittee shall use time travel studies that are less than five years old.

e. Time travel studies are only required for pesticide applications that flow to a 

point of compliance.

6. Sampling and Analytical Procedures

a. The permittee shall ensure that all samples and measurements taken to meet the 

requirements of this permit are representative of the volume, concentration, and 

nature of the monitored parameters.

b. The permittee shall ensure that sampling and analytical methods used to meet the 

monitoring requirements specified in this permit conform to the latest revision of 

the Guidelines Establishing Test Procedures for the Analysis of Pollutants 

contained in 40 CFR 136 or to the latest revision of Standard Methods for the 

Examination of Water and Wastewater (APHA).

c. Acrolein testing may follow the procedures of Solid Waste Method 8260.

Condition 8. FISH MANAGEMENT

A. ALLOWED ACTIVE INGREDIENTS

1. Rotenone

2. Antimycin-A
Page | 20

Washington State Pesticide Permit Conditions

3. Potassium Permanganate (KMnO4) is the only chemical permitted to neutralize 

rotenone treated waters when necessary to prevent damage to non-targeted organisms 

and maintain water quality outside of the area intended for rotenone treatment.

B. ADDITIONAL RESTRICTIONS

1. In order to prevent unnecessary damage to the environment, the permittee shall 

follow the best management practices defined below on the day of application.

Powdered rotenone formulations shall be applied in such a way that minimizes 

airborne dust, using the best available technology such as the method outlined in 

“Utah’s Procedure for Mixing Powdered Rotenone into a Slurry” (Thompson et al. 

2001).

In order to prevent an exceedance of water quality standards outside the area intended 

for rehabilitation, rotenone treatment should only take place in lakes that are not 

discharging to downstream waters. This is accomplished by limiting treatments to 

lakes with closed basins or conducting treatments only during periods of low water, 

usually September or October.

In instances where treated waters may potentially discharge to downstream waters 

resulting in an exceedance of water quality standards outside the treatment area, such 

discharge shall be prevented by installing adequate temporary water control 

measures.

When it is necessary and unavoidable to discharge rotenone treated waters to 

downstream waters, the permittee shall conduct pretreatment water quality and 

biological monitoring.

Treated waters shall be effectively neutralized and detoxified using potassium 

permanganate so that water quality standards are not exceeded below the 

neutralization zone. For purposes of this section, neutralization zone is defined as the 

downstream waters where potassium permanganate has been applied but has not yet 

fully neutralized the rotenone, due to the lag time normally associated with 

detoxification. The neutralization zone is typically considered the distance that water 

can be expected to travel in 20 minutes. Since the neutralization zone may contain 

toxic levels of rotenone and potassium permanganate, some fish mortalities may 

occur in this zone.

Below the neutralization zone, rotenone must be totally neutralized and residual 

potassium permanganate levels maintained at a non-toxic level of 1 mg/L, not to 

exceed 2 mg/L. Live trout cars will be set up below the neutralization zone to 

monitor the effectiveness of detoxification measures.
Page | 21

Washington State Pesticide Permit Conditions

Detoxification procedures must utilize calibrated equipment to achieve the minimum

effective concentration of potassium permanganate to oxidize the rotenone within the

neutralization zone. Potassium permanganate concentrations must be closely 

monitored using a field calibrated spectrophotometer to keep residual permanganate 

levels at a level that effectively neutralizes rotenone while preventing damage to 

aquatic life downstream of the treatment area and neutralization zone.

2. In order to minimize the discharge of inert ingredients (e.g. Benzene), if using a 

rotenone formulation containing Benzene, only powdered (non-liquid) rotenone 

formulations shall be utilized, except in very limited cases when the Permittee finds it 

necessary to treat waters that are inaccessible by boat, such as weedy shorelines or 

marshy areas.

3. Monitoring

The Permittee must conduct monitoring on each water body treated with aquatic 

pesticides to determine the extent and duration of the short-term water quality 

reduction resulting from rotenone applications. The Permittee must monitor 

according to Tables 7 and 8.
Page | 22

Washington State Pesticide Permit Conditions

Table 7: Rotenone Monitoring Schedule

Parameters Units Minimum Sampling 

Frequency Sample Type

Rotenone Toxicity - Trout Bioassay: 48-hr live box 

test (5 trout); 100% survival of rainbow trout

Number of days until

100% survival

Once post-treatment, approximately

3-8 weeks after treatment

Observation

(no lab accreditation

required)

If rotenone formulations containing Benzene are 

used: VOC, semi-VOC, plus any other inert

ingredients listed on MSDS1

μg/L 1. 24 hours after treatment; 

2. four weeks after treatment

Grab

pH Standard Once pretreatment Grab

Temperature °F Once pretreatment Grab

Alkalinity2 mg/L CaCO3 Once pretreatment2 Grab

Organic demand2,3 Standard 3 Once pretreatment2 Grab

Zooplankton sampling See below 4 1. Pre-treatment;

2. Six months after treatment; 

3. One year after treatment

Composite4

1 If rotenone formulations containing Benzene are used, test for the following parameters: VOC (EPA method 8310) and semi-VOC (EPA 

method 502.2). Also test for any other inert ingredients listed on MSDS (i.e. the MSDS for Prentox ® PrenfishTM Toxicant lists 

naphthalene; 1,2,4-trimethylbenzene; and acetone).

2 Only if neutralization of rotenone with potassium permanganate is required.

3 Use the guidelines provided in Engstrom-Heg (1971) to determine organic demand for KMnO4.

4 Lakes only. Zooplankton sampling protocols set forth on Page 4-5 of “Water Quality Assessments of Selected Lakes within Washington 

State - 1998” Department of Ecology, December 2000, Publication No. 00-03-039
Page | 23

Washington State Pesticide Permit Conditions

Table 8: Downstream Monitoring Schedule

Parameters Units Minimum Sampling Frequency Sample Type

Rotenone Toxicity - Trout Bioassay: 48-hour

live box test (5 trout)

% Survival 1. Begin test at time of treatment 

and 2. Repeat at one week 

intervals until upstream treated 

water is detoxified per upstream 

bioassay.

Observation (no lab

accreditation required)

Rotenone 1 mg/L Once 24 hours following 

treatment

Grab

If rotenone formulations containing Benzene are

used: VOC, semi-VOC, plus any other inerts2

ug/L 1. 24 hours after treatment, and 

2. four weeks after treatment

Grab

pH Standard Once pretreatment Grab

Temperature °F Once pretreatment Grab

Alkalinity3 mg/L CaCO3 Once pretreatment3 Grab

Organic Demand3,4 Standard4 Once pretreatment3,4 Grab

Zooplankton Sampling See Below5 1. Pre-treatment, 

2. Six months after treatment, and 

3. One year after treatment

Composite5

1 Analyze using methods set forth in Dawson et al. (1983);

2 If rotenone formulations containing Benzene are used, test for the following parameters: VOC (EPA method 8310) and semiVOC (EPA method 502.2). Also test for any other inert ingredients listed on MSDS (i.e. the MSDS for Prentox ®

PrenfishTM Toxicant lists naphthalene; 1,2,4-trimethylbenzene; and acetone).

3 Only if neutralization of rotenone with potassium permanganate is required.

4 Use the guidelines in Engstrom-Heg (1971) for measuring organic demand for KMnO4.

5 Lakes only. Zooplankton sampling protocols set forth on Page 4-5 of “Water Quality Assessments of Selected

Lakes within Washington State - 1998” Department of Ecology, December 2000, Publication No. 00-03-039;
Page | 24

Washington State Pesticide Permit Conditions

6 “Macroinvertebrate monitoring” includes gathering benthic invertebrate samples and summarizing the data using the benthic index of 

biotic integrity (B-IBI) and a ratio measure of the number of observed taxa divided by the number of expected taxa, the River Invertebrate 

Prediction and Classification System (RIVPACS). All bioassessment sampling and related habitat survey data, laboratory analysis, 

quality assurance, and data analysis shall follow the protocols in Benthic Macroinvertebrate Biological Monitoring Protocols for Rivers 

and Streams: 2001 Revision, Plotnikoff and Wiseman, August 2001 (http://www.ecy.wa.gov/biblio/0103028.html).
Page | 25

Washington State Pesticide Permit Conditions

Condition 9. INVASIVE MOTH CONTROL

A. ALLOWED ACTIVE INGREDIENTS

1. Bacillus thuringiensis var. kurstaki based pesticides

2. Adjuvants that may be used for invasive moth control include latex-based adjuvants.

B. ADDITIONAL RESTRICTIONS

1. Monitoring Requirements

The permittee must monitor all pesticide application activities. Minimum monitoring 

must include the parameters listed in Table 9. The permittee must keep records of 

their monitoring an make it available upon request.

One sampling event must be conducted per treatment season. When treatments are 

not conducted, no sampling is required. One grab sample of water must be tested for 

concentrations pesticide active ingredient before and immediately after the 

application (including indirect applications) to waters. This monitoring is required to 

determine impacts on the receiving environment.

Condition 10. AQUATIC INVASIVE SPECIES

A. ALLOWED ACTIVE INGREDIENTS

1. Chloride for marine and freshwater application. 

2. Potassium chloride for marine and freshwater application. 

3. Chlorine compounds including chlorine dioxide, sodium chlorite, sodium 

hypochlorite, and calcium hypochlorite for marine and freshwater application. 

4. Acetic acid for marine and freshwater application 

5. Calcium hydroxide/oxide (lime) and carbon dioxide for marine and freshwater 

application. 

6. Rotenone for freshwater application. 

7. Antimycin-A for freshwater application. 

8. Potassium permanganate (KMnO4) for freshwater application. 

Table 9: Invasive Moth Monitoring

Item or Parameter Minimum Frequency Type of Sample 

Date, start/stop times for application Each day when spraying occurs Record 

Total acres sprayed Each day when spraying occurs Record 

Wind speed Each day when spraying occurs Record 

Location of application Each day when spraying occurs Record 

Name of applicator Each day when spraying occurs Record 
Page | 26

Washington State Pesticide Permit Conditions

9. Endothall, Monopotassium salt (e.g. Hydrothol)

10. Sodium carbonate peroxyhydrate for freshwater application. 

11. Methoprene for freshwater application.

12. Chelated copper compounds for freshwater application.

13. Pseudomonas fluorescens (strain CLO145) for freshwater application.

14. Heating/cooling (temperature alteration) for marine and freshwater application.

B. ADDITIONAL RESTRICTIONS

1. Activities Covered

Activities covered include management activities for nonnative invasive aquatic 

animals and nonnative invasive marine algae that result in the discharge of chemicals 

or control products into surface waters of the state of Washington. Surface waters 

include fresh, brackish, marine, and estuarine waters. Products subject to this 

condition include algaecides, herbicides, insecticides, molluscicides, piscicides and 

any other chemical or product appropriate for use in managing these organisms.

Management activities are organized into two categories: Marine Projects and 

Freshwater Projects.

2. Marine Projects

Marine projects occur in marine or estuarine waters and target nonnative invasive 

animals and nonnative invasive algal species. Marine projects are allowed for:

a. Animal species as identified in WAC 220-12-090.

b. Animals or marine algae listed on the Washington Aquatic Nuisance Species 

Committee “watch list” of invasive species or on the Washington Invasive 

Species Council (WISC) management priority list

(http://www.invasivespecies.wa.gov/priorities.shtml).

c. Animals listed by the United States Fish and Wildlife Service (USFWS) as 

injurious wildlife under the Lacey Act (18 U.S.C. 42; 50 CFR 16).

d. Nonnative potentially invasive marine animals and algae not listed on the above 

lists, as determined by Ecology in consultation with WDFW, or WDNR, or 

WSDA, or WISC, or the Washington Aquatic Nuisance Species (ANS) 

Committee, or applicable federal agencies such as the USFWS.

3. Freshwater Projects
Page | 27

Washington State Pesticide Permit Conditions

Freshwater projects occur in rivers, streams, lakes, ponds, brackish inland water 

bodies, wetlands, or wet areas and target nonnative invasive freshwater animals. 

Freshwater projects are allowed for:

a. Prohibited or unlisted freshwater animals as identified in WAC 220-12-090.

b. Freshwater animals listed on the Washington Aquatic Nuisance Species 

Committee “watch list” of invasive species or on the WISC management priority 

list (http://www.invasivespecies.wa.gov/priorities.shtml).

c. Freshwater animals listed by the USFWS as injurious wildlife under the Lacey 

Act (18 U.S.C. 42; 50 CFR 16).

d. Nonnative potentially invasive freshwater animals not listed on the above lists, as 

determined by Ecology in consultation with WDFW, or WDNR, or WSDA, or 

WISC, or the ANS Committee, or applicable federal agencies such as the 

USFWS.

4. Specific Restrictions on the Application of Products

a. Except for emergencies, the Permittee must limit treatments that restrict public 

water use during weekends in high use areas or highly populated areas.

b. Permittees must comply with the specific application restrictions for each product 

as identified in Tables 10 and 11. The Treatment Windows identified in Tables 

10 and 11 were developed to avoid adverse impacts to priority species (federaland-state-listed and other sensitive and vulnerable species). WDFW may 

periodically update the Treatment Windows when new information becomes 

available. Restrictions/Advisories identified in Tables 10 and 11: Recreational 

restrictions apply to swimming, boating, water skiing, etc. Swimming restrictions 

apply to primary contact activities such as swimming, wading, and water skiing.

c. The Permittee must use Washington Department of Natural Resources Natural 

Heritage Program database to determine if sensitive, threatened, or endangered 

(rare) plants are present in the proposed treatment area. If a rare plant does occur 

in or around the waterbody, the Permittee survey for the rare plant and mitigate 

for impacts if necessary The rare plant database is located at 

http://www1.dnr.wa.gov/nhp/refdesk/plants.html.
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Washington State Pesticide Permit Conditions

Table 10: Marine Application Restrictions

Chemical or 

Control 

Measure

Treatment

Windows

Restrictions/

Advisories Treatment Limitations

Sodium 

chloride & 

Potassium 

chloride 

No, but check 

with WDFW 

before 

treatment to 

determine 

critical habitat 

areas. 

None • Limit treatments to the lowest effective concentration or amount of these salts 

necessary to kill the targeted organism.

• Limit treatment to docks, boat hulls, and fixed objects or defined areas.

• Spray or apply directly on target organisms when if they are out of water (apply 

at low tide).

• The Permittee may treat defined areas, such as marinas or coves, if the Permittee 

can limit water exchange behind impermeable barriers.

Chlorine No, but check 

with WDFW 

before 

treatment to 

determine 

critical habitat 

areas. 

If treating in an area 

accessible by the 

public, post buoys 

around the treatment 

area.

• Limit treatments to the lowest effective concentration or amount (e.g,. if using 

swimming pool pellets) to kill the targeted organism.

• Where practicable, use chlorine dioxide/sodium chlorite instead of sodium 

hypochlorite or calcium hypochlorite.

• Use under tarpaulins or impermeable covers secured over the invasive 

organisms. Seal edges to the substrate as thoroughly as possible.

• Limit treatment to docks, boat hulls, and fixed objects or defined areas where the 

Permittee can secure impermeable covers.

• Leave tarpaulins on for at least one day before removing. If this is not possible, 

test for chlorine using a swimming pool test kit and neutralize any residual 

chlorine using ascorbic acid (vitamin C) before removing the cover. 

Acetic Acid No, but check 

with WDFW 

before 

treatment to 

determine 

critical habitat 

areas. 

If treating in an area 

accessible by the 

public, post buoys 

around the treatment 

area. 

Restrict swimming for 

12 hours in the 

treatment area if 

spraying directly on 

organisms.

• Limit treatments to the lowest effective concentration to kill the targeted 

organism (vinegar concentrations – 5-10% are reported to be effective for softbodied marine organisms).

• Use under tarpaulins or impermeable covers secured over the invasive 

organisms. Seal the edges to the substrate as thoroughly as possible. 

• Limit treatment to docks, boat hulls, and fixed objects or defined areas where the 

Permittee can secure impermeable covers.

• Remove covers as soon as the target organisms are dead.

• Spray directly on target organisms if they are out of water (tidal).

• The Permittee may treat defined areas, such as marinas, if the Permittee can limit 
Page | 29

Washington State Pesticide Permit Conditions

Restrict public access 

to area when diluting 

concentrated acid.

water exchange behind impermeable barriers.

Calcium 

hydroxide 

/oxide (lime) 

No, but check 

with WDFW 

before 

treatment to 

determine 

critical habitat 

areas. 

If in an area accessible 

by the public, post 

buoys around the 

treatment area. 

• Limit treatments to the lowest effective concentration or amount necessary to kill 

the targeted organism.

• Use under tarpaulins or impermeable covers secured over the invasive organisms 

and limit treatment to docks, boat hulls, and fixed objects or defined areas where 

the Permittee can secure impermeable covers.

• Remove covers as soon as the target organism is dead.

• For direct applications, apply only to target organisms (e.g. invasive 

echinoderms). Do not treat un-infested areas. 

Heat/Freezing No, but check 

with WDFW 

before 

treatment to 

determine 

critical habitat 

areas. 

None • Limit treatment to docks, boat hulls, and fixed objects or defined areas 

• May use in conjunction with pressure washing to remove invasive organisms 

from docks and infrastructure. 

Table 11: Freshwater Application Restrictions

Chemical Treatment 

Windows

Restrictions/

Advisories Treatment Limitations

Sodium 

chloride &

Potassium 

chloride 

No, but check 

with WDFW 

before 

treatment to 

determine 

critical habitat 

areas. 

None • Use under tarpaulins or impermeable covers secured over the invasive 

organisms. 

• Limit treatment to docks, boat hulls, and fixed objects or defined areas where 

the Permittee can secure impermeable covers. 

• The Permittee may treat defined areas, such as coves or marinas, if the 

Permittee can limit water exchange behind impermeable barriers. 

Whole Lake 
Page | 30

Washington State Pesticide Permit Conditions

• The Permittee may treat small water bodies with potassium chloride where the 

threat of the invasive species outweighs other environmental damage and 

where water can be contained. 

• For nonnative mussel eradication projects with potassium chloride, the 

Permittee must take steps to restore native mussel populations in the treated 

water body, when practicable. 

Chlorine Yes, also 

check with 

WDFW 

before 

treatment to 

determine 

critical habitat 

areas. 

Advise no swimming 

in area when placing 

chemicals under 

covers and removing 

covers. 

• Limit treatments to the lowest effective concentration or amount (e.g. if using 

swimming pool pellets) necessary to kill the targeted organism. 

• Where practicable, use chlorine dioxide/sodium chlorite instead of sodium 

hypochlorite or calcium hypochlorite.

• Use under tarpaulins or impermeable covers secured over the invasive 

organisms. Seal edges to the substrate as thoroughly as possible. 

• Limit treatment to docks, boat hulls, and fixed objects or defined areas where 

the Permittee can secure impermeable covers. 

• Leave tarpaulins on for at least one day before removing. If this is not possible, 

test for chlorine using a swimming pool test kit and neutralize any residual 

chlorine using ascorbic acid (vitamin C) before removing the cover.

Acetic Acid No, but check 

with WDFW 

before 

treatment to 

determine 

critical habitat 

areas. 

Advise no swimming 

in area when placing 

chemicals under 

covers and removing 

covers. 

• Limit treatments to the lowest effective concentration to kill the targeted 

organism (vinegar concentrations – 5-10% are reported to be effective for softbodied organisms). 

• Use under tarpaulins or impermeable covers secured over the invasive 

organisms. Seal the edges to the substrate as thoroughly as possible. 

• Limit treatment to docks, boat hulls, and fixed objects or defined areas where 

the Permittee can secure impermeable covers. 

• Remove covers as soon as the target organisms are dead.

Calcium 

hydroxide/ 

oxide (lime) 

No No • Whole water body applications permitted. 

• The pH of the receiving water must remain between 6 and 9. Stop treatment if 

pH goes above 9.0. 

Rotenone Yes, also 

check with 

WDFW 

before 

Follow EPA label 

restrictions 

• Endangered Species Act (ESA) listed fish species must not be present at the 

time of treatment and for three months following treatment, unless the state and 

federal fish agencies approve a treatment. 

• Except for emergencies or when in situations where invasive species may move 
Page | 31

Washington State Pesticide Permit Conditions

treatment to 

determine 

critical habitat 

areas. 

out of water body if treatment is delayed, limit treatment to periods of low 

water, usually September or October, unless the water body has a closed basin. 

• Limit airborne dust. In open water areas accessible by boat, use powdered 

rotenone mixed with water and apply as a slurry.

• Use liquid rotenone for spot applications only in areas that are not practicably 

accessible by boat.

• Unless the outlet is being treated for invasive species, in water bodies with 

flowing outlets, rotenone must be neutralized to eliminate downstream impacts. 

Below the neutralization zone (distance the water travels in 20 minutes), the 

rotenone must be totally neutralized using potassium permanganate. Residual 

potassium permanganate, not to exceed 2 mg/L past the neutralization zone. 

• Follow monitoring requirements in Tables 12-15.

• Restock the water body with appropriate fish species after eradication of the 

target species.

• Unless the outlet is being treated for invasive species, in water bodies with 

flowing outlets, rotenone must be neutralized to eliminate downstream impacts. 

Below the neutralization zone (distance the water travels in 20 minutes), the 

rotenone must be totally neutralized using potassium permanganate. Residual 

potassium permanganate, not to exceed 2 mg/L past the neutralization zone. 

• Follow monitoring requirements in Tables 12-15.

• Restock the water body with appropriate fish species after eradication of the 

target species. 

Antimycin-A Yes, also 

check with 

WDFW 

before 

treatment to 

determine 

critical habitat 

areas. 

Follow EPA label 

restrictions 

• Use only in shallow water bodies and streams. 

• ESA-listed species must not be present at the time of treatment and for three 

months following treatment, unless the state and federal fish agencies approve 

the treatment.

• Except for emergencies or in situations where invasive species may move out 

of water body if treatment is delayed, limit treatment to periods of low water, 

usually September or October, unless the water body has a closed basin. 

• Unless the outlet is being treated for invasive species, in water bodies with 

flowing outlets, antimycin-A must be neutralized to eliminate downstream 

impacts. Below the neutralization zone (distance the water travels in 20 
Page | 32

Washington State Pesticide Permit Conditions

minutes), the antimycin-A must be totally neutralized using KMnO4. Residual 

KMnO4, not to exceed 2 mg/L past the neutralization zone. 

• Follow monitoring requirements in Tables 12-15.

• Restock the water body with appropriate fish species after eradication of the 

target species.

Potassium 

permanganate

(KMnO4)

Yes, also 

check with 

WDFW 

before 

treatment to 

determine 

critical habitat 

areas. 

• Use under tarpaulins or impermeable covers secured over the invasive 

organisms.

• Limit treatment to docks, boat hulls, and fixed objects or defined areas where 

the Permittee can secure impermeable covers.

• The Permittee may treat defined areas, such as marinas, if the Permittee can 

limit water exchange behind impermeable barriers.

• The Permittee may treat enclosed, small water bodies where the threat of the

invasive species outweighs other environmental damage.

• When used to neutralize rotenone or antimycin treated waters – use calibrated 

equipment to achieve the minimum effective concentration of potassium 

permanganate necessary to oxidize the rotenone within the neutralization zone.

Endothall 

(Hydrothol 

191TM) 

Yes Contact recreational 

restriction during and 

24-hours after 

treatment (in the entire 

water body) 

• Treatment shall occur from the shoreline outward into the waterbody.

• Juvenile salmon species and ESA-listed species must not be present at the time 

of treatment. 

Sodium 

carbonate 

peroxyhydrate 

No Swimming advisory 

during treatment, and 

2-hour post-treatment 

None 

Methoprene No None • Do not apply in state-listed restricted use areas identified Condition 4.B.4 

without consulting with WDFW habitat biologists. 

Chelated 

Copper 

Yes None • Use lowest effective concentration to kill targeted organism 

• Sediment copper concentrations in the treatment area must be less than 110 

mg/kg (emergency exception for zebra or quagga mussel treatment, if there are 

no other suitable controls available). 

• Do not apply copper if the water hardness is less than 50 mg/L expressed as 

calcium carbonate (emergency exception for zebra or quagga mussel treatment). 
Page | 33

Washington State Pesticide Permit Conditions

• Do not apply copper if the pH is less than 6.0 (emergency exception for zebra 

or quagga mussel treatment). 

• Juvenile salmon species and Endangered Species Act listed species must not be 

present at the time of treatment, unless the state and federal fish agencies 

approve the treatment. 

P. fluorescens 

strain CLO145 

No None None 

Heating/

cooling 

No,

check with 

WDFW for 

critical habitat 

areas. 

None • Limit treatment to docks, boat hulls, and fixed objects or defined areas. 

• Direct heat or cold only at target organisms 

• May use in conjunction with pressure washing to remove invasive organisms 

from docks and infrastructure. 
Page | 34

Washington State Pesticide Permit Conditions

5. Monitoring for Specific Chemicals

The Permittee must monitor for specific chemicals/products as identified in Tables 12-15. 

All laboratory results for chemical concentrations must include the following 

information: 

a. Sampling date

b. Sample location (water body name and location within the water body)

c. Date of analysis 

d. Parameter name 

e. Chemical Abstract Service (CAS) number 

f. Analytical method number 

g. Method detection limit (MDL) 

h. Laboratory practical quantitation limit (PQL) 

i. Reporting units 

j. Concentration detected
Page | 35

Washington State Pesticide Permit Conditions

Table 12: Invasive Species Monitoring

Chemical or Control Measures Specific Monitoring Requirements 

Sodium chloride & 

Potassium chloride 

• For whole lake treatments or treatments of areas sequestered behind barriers within a larger fresh water 

body, the Permittee must at a minimum measure potassium or sodium chloride concentrations at one or 

more representative sampling locations pre-treatment, one, and five days post-treatment to determine 

actual water body concentrations.

Chlorine • The Permittee must monitor for chlorine concentrations under impermeable covers on a representative 

number of sites before removing the covers. Permittee may use swimming pool test kits for this purpose.

• If monitoring demonstrates that undercover chlorine concentrations are always under 0.5 mg/L before 

removal (at a representative number of sites and for the same chlorine formulation), the Permittee may 

suspend monitoring upon Ecology approval.

Acetic Acid • When removing impermeable covers, monitor pH levels in the receiving water before and immediately 

after cover removal 

• When directly spraying the organisms, monitor the pH of receiving waters directly adjacent to the 

organisms immediately before and after treatment. 

Calcium hydroxide/oxide 

(lime) 

For Freshwater Treatments Only

• Measure pH once a day before treatment; once in the morning and once in the afternoon during treatment; 

and for ten days following treatment at a representative site within the water body. 

• For applications using continuous injection systems, measure pH once in the morning and once in the 

afternoon 

Rotenone and Antimycin-A • See Tables 13-15 for specific monitoring requirements for rotenone and antimycin-A. 

Copper • Before applying copper, measure sediment copper concentrations in a composite sample of sediment from 

a representative treatment area (composite sample from 5 areas with sediment taken from the top 5 cm of 

sediment and homogenized).

• Measure pH and hardness prior to treatment.

Heat/Freezing • If used in conjunction with pressure washing to remove invasive organisms from docks and infrastructure, 

measure the temperature of the receiving water immediately before and immediately after the activity.
Page | 36

Washington State Pesticide Permit Conditions

Table 13: Pre--treatment monitoring for rotenone and antimycin-A

Parameters Units Minimum Sampling 

Frequency Type Sampling Point

pH Standard Once Grab Representative 

Temperature °Fahrenheit (F) Once Grab Representative 

Alkalinity1 mg/L CaCO3 Once Grab Worst-case scenario 

Organic demand1,2 Standard Once Grab Worst-case scenario 

1

Only required when the Permittee uses potassium permanganate to neutralize rotenone. 

2

The Permittee must use the guidelines provided in Engstrom-Heg (1971) to determine organic demand for KMnO4. 

Table 14: Post-treatment monitoring for rotenone and antimycin-A

Parameters Units Minimum Sampling 

Frequency Type Sampling Point

pH Standard Once Grab Representative 

Temperature °F Once Grab Representative 

Rotenone Trout 

Toxicity 

Bioassay: 24-hr 

live box test 

(five trout); 60% 

trout survival 

Hours until 60% 

survival 

Once approximately three to 

eight weeks after treatment 

Observation 

(No lab 

accreditation 

required) 

Worst-case scenario 

If rotenone

formulations 

containing 

Benzene are 

used: Volatile 

Organic 

Compound 

(VOC), semi 

μg/L Four weeks post treatment and 

every week thereafter until 

non-detection 

Grab Worst-case scenario 
Page | 37

Washington State Pesticide Permit Conditions

VOC, and any 

other inert 

ingredients 

listed on the 

Material Safety 

Data Sheet 

(MSDS)1

1

The Permittee must sample for VOC and semi-VOC when the liquid rotenone product used contains solvents that are listed on the 

label and/or the MSDS. 

Table 15: Monitoring for downstream and neutralized waters after rotenone or antimycin-A treatment

Parameters Units

Minimum 

Sampling 

Frequency

Type Sampling Point

pH Standard • Once pretreatment 

• Once posttreatment 

Grab Representative 

Temperature °F • Once pretreatment 

• Once posttreatment 

Grab Representative 

Alkalinity1 mg/L as CaCO3 • Once pretreatment Grab Worst-case scenario 

Organic 

demand1,2 

Standard • Once pretreatment Grab Worst-case scenario 

Rotenone (if 

applied)3 

mg/L • Once 24 

hours after 

treatment 

Grab Worst-case scenario 
Page | 38

Washington State Pesticide Permit Conditions

If rotenone

formulations 

containing 

Benzene are 

used : VOC, 

semi-VOC, and 

any other inert 

ingredients listed 

on the MSDS3

μg/L • 24 hours post 

treatment 

• Four weeks 

post 

treatment 

Grab Worst-case scenario 

Antimycin-A (if 

applied)3 

μg/L • Once 24 

hours 

following 

treatment 

Grab Worst-case scenario 

Rotenone Trout 

Toxicity 

Bioassay: 24-hr 

live box test (5 

trout) 

% survival • Begin test at 

time of 

treatment 

• Repeat 

weekly until 

upstream 

water is 

detoxified. 

Observation 

(No lab 

accreditation 

required) 

Worst-case scenario 

1 Only required when the Permittee uses potassium permanganate to neutralize the rotenone. 

2 The Permittee must use the guidelines provided in Engstrom-Heg (1971) to determine organic demand for KMnO4. 3 The Permittee must use EPA approved testing methods in 40 CFR Part 136
Page | 39

Washington State Pesticide Permit Conditions

Condition 11. FOREST CANOPY PEST CONTROL

Permittees performing forest canopy pest control must follow the requirements in Title 76 RCW

(Forests and Forest Products).

Condition 12: ANNUAL REPORTING

A. Permittees must submit an annual report to Ecology containing the following for the 

treatment season:

1. Permit Number,

2. Permittee Name,

3. Name of the location/waterbody treated.,

4. Active ingredient(s) used(e.g. Bti, permethrin, etc.),

5. Total amount of active ingredient applied for each season,

6. Total acreage applied to,

7. Measurement units (pounds or gallons), and

8. Attach any monitoring results taken as required by Conditions 4 – 12 with the annual 

report.

9. Attach any Treatment Window determinations from WDFW to the annual report, 

including lake name, location (lat/long), treatment windows dates, and the reason for 

the treatment restrictions (e.g. salmonid smolts, grebe nesting, etc). This should be in 

a letter or email from WDFW staff confirming the Treatment Window change.

B. Ecology must receive the annual report by December 31 of each year. Mail the annual 

report to:

Department of Ecology

Water Quality Program

Attn: Aquatic Pesticides Permit Manager

PO Box 47600

Olympia, WA 98504

Condition 13. PUBLIC NOTICE

Ecology includes public notification and treatment area postings in the pesticide permits it issues. 

State law does not require the public notification and treatment area postings. They are intended 

to respect the public’s right to know, and to protect the public health and welfare by reducing the 

public’s exposure to pesticides. Ecology strongly recommends that the public be provided with 

public notice of pesticide treatments through public notification and treatment area postings.
Page | 40

Washington State Pesticide Permit Conditions

The permittee should publish a public notice in a newspaper of general circulation in the area 

where treatment will occur, prior to the first application of the season. The newspaper notice 

should contain:

i. Proposed schedule of treatments for the season. 

ii. Common name of the water body to be treated. 

iii. Chemicals to be used.

iv. Any water use restrictions or precautions

v. Contact information of the Permittee and any agency staff involved. 

vi. Ecology’s regional twenty-four (24) hour Emergency number. 

vii. Notification shall explain the project and explain that any treated areas will be 

flagged no more than 48 hours before treatment begins.

The Permittee is encouraged to use Ecology posting templates contained in each pesticide permit 

to post the treated areas, where feasible, at 100-foot intervals to 400 feet beyond the boundary of 

the treatment area. Signs posting treatment areas should be posted before treatment commenced, 

but no more than 48 hours before the start of treatment. Signs should also be posted in the 

commonly spoken language of the area where treatment is occurring.