AMENDATORY SECTION (Amending WSR 11-09-090, filed 4/20/11, effective 

5/21/11)

WAC 173-201A-020 Definitions. The following definitions are intended to facilitate the use of chapter 173-201A WAC:

"1-DMax" or "1-day maximum temperature" is the highest water temperature reached on any given day. This measure can be obtained using 

calibrated maximum/minimum thermometers or continuous monitoring 

probes having sampling intervals of thirty minutes or less.

"7-DADMax" or "7-day average of the daily maximum temperatures" 

is the arithmetic average of seven consecutive measures of daily maximum temperatures. The 7-DADMax for any individual day is calculated by 

averaging that day's daily maximum temperature with the daily maximum 

temperatures of the three days prior and the three days after that 

date.

"Action value" means a total phosphorus (TP) value established at 

the upper limit of the trophic states in each ecoregion (see Table 

230(1)). Exceedance of an action value indicates that a problem is 

suspected. A lake-specific study may be needed to confirm if a nutrient problem exists.

"Actions" refers broadly to any human projects or activities.

"Acute conditions" are changes in the physical, chemical, or biologic environment which are expected or demonstrated to result in injury or death to an organism as a result of short-term exposure to the 

substance or detrimental environmental condition.

"AKART" is an acronym for "all known, available, and reasonable 

methods of prevention, control, and treatment." AKART shall represent 

the most current methodology that can be reasonably required for preventing, controlling, or abating the pollutants associated with a discharge. The concept of AKART applies to both point and nonpoint sources of pollution. The term "best management practices," typically applied to nonpoint source pollution controls is considered a subset of 

the AKART requirement.

"Background" means the biological, chemical, and physical conditions of a water body, outside the area of influence of the discharge 

under consideration. Background sampling locations in an enforcement 

action would be up-gradient or outside the area of influence of the 

discharge. If several discharges to any water body exist, and enforcement action is being taken for possible violations to the standards, 

background sampling would be undertaken immediately up-gradient from 

each discharge.

"Best management practices (BMP)" means physical, structural, 

and/or managerial practices approved by the department that, when used 

singularly or in combination, prevent or reduce pollutant discharges.

"Biological assessment" is an evaluation of the biological condition of a water body using surveys of aquatic community structure and 

function and other direct measurements of resident biota in surface 

waters.

"Bog" means those wetlands that are acidic, peat forming, and 

whose primary water source is precipitation, with little, if any, outflow.

"Carcinogen" means any substance or agent that produces or tends 

to produce cancer in humans. For implementation of this chapter, the 

term carcinogen will apply to substances on the United States Environmental Protection Agency lists of A (known human) and B (probable human) carcinogens, and any substance which causes a significant in­

[ 1 ] OTS-6831.2
creased incidence of benign or malignant tumors in a single, well conducted animal bioassay, consistent with the weight of evidence approach specified in the United States Environmental Protection Agency's Guidelines for Carcinogenic Risk Assessment as set forth in 51 FR 

33992 et seq. as presently published or as subsequently amended or republished.

"Chronic conditions" are changes in the physical, chemical, or 

biologic environment which are expected or demonstrated to result in 

injury or death to an organism as a result of repeated or constant exposure over an extended period of time to a substance or detrimental 

environmental condition.

"Compliance schedule" or "schedule of compliance" is a schedule 

of remedial measures included in a permit or an order, including an 

enforceable sequence of interim requirements (for example, actions, 

operations, or milestone events) leading to compliance with an effluent limit, other prohibition, or standard.

"Created wetlands" means those wetlands intentionally created 

from nonwetland sites to produce or replace natural wetland habitat.

"Critical condition" is when the physical, chemical, and biological characteristics of the receiving water environment interact with 

the effluent to produce the greatest potential adverse impact on 

aquatic biota and existing or designated water uses. For steady-state 

discharges to riverine systems the critical condition may be assumed 

to be equal to the 7Q10 flow event unless determined otherwise by the 

department.

"Damage to the ecosystem" means any demonstrated or predicted 

stress to aquatic or terrestrial organisms or communities of organisms 

which the department reasonably concludes may interfere in the health 

or survival success or natural structure of such populations. This 

stress may be due to, but is not limited to, alteration in habitat or 

changes in water temperature, chemistry, or turbidity, and shall consider the potential build up of discharge constituents or temporal increases in habitat alteration which may create such stress in the long 

term.

"Department" means the state of Washington department of ecology.

"Designated uses" are those uses specified in this chapter for 

each water body or segment, regardless of whether or not the uses are 

currently attained.

"Director" means the director of the state of Washington department of ecology.

"Drainage ditch" means that portion of a designed and constructed 

conveyance system that serves the purpose of transporting surplus water; this may include natural water courses or channels incorporated 

in the system design, but does not include the area adjacent to the 

water course or channel.

"Ecoregions" are defined using EPAs Ecoregions of the Pacific 

Northwest Document No. 600/3-86/033 July 1986 by Omernik and Gallant.

"Enterococci" refers to a subgroup of fecal streptococci that includes S. faecalis, S. faecium, S. gallinarum, and S. avium. The enterococci are differentiated from other streptococci by their ability 

to grow in 6.5% sodium chloride, at pH 9.6, and at 10°C and 45°C.

"E. coli" or "Escherichia coli" is an aerobic and facultative 

gram negative nonspore forming rod shaped bacterium that can grow at 

44.5 degrees Celsius that is ortho-nitrophenyl-B-D-galactopyranoside 

(ONPG) positive and Methylumbelliferyl glucuronide (MUG) positive.

"Existing uses" means those uses actually attained in fresh or 

marine waters on or after November 28, 1975, whether or not they are 

[ 2 ] OTS-6831.2
designated uses. Introduced species that are not native to Washington, 

and put-and-take fisheries comprised of nonself-replicating introduced 

native species, do not need to receive full support as an existing 

use.

"Extraordinary primary contact" means waters providing extraordinary protection against waterborne disease or that serve as tributaries to extraordinary quality shellfish harvesting areas.

"Fecal coliform" means that portion of the coliform group which 

is present in the intestinal tracts and feces of warm-blooded animals 

as detected by the product of acid or gas from lactose in a suitable 

culture medium within twenty-four hours at 44.5 plus or minus 0.2 degrees Celsius.

"Geometric mean" means either the nth root of a product of n factors, or the antilogarithm of the arithmetic mean of the logarithms of 

the individual sample values.

"Ground water exchange" means the discharge and recharge of 

ground water to a surface water. Discharge is inflow from an aquifer, 

seeps or springs that increases the available supply of surface water. 

Recharge is outflow downgradient to an aquifer or downstream to surface water for base flow maintenance. Exchange may include ground water discharge in one season followed by recharge later in the year.

"Hardness" means a measure of the calcium and magnesium salts 

present in water. For purposes of this chapter, hardness is measured 

in milligrams per liter and expressed as calcium carbonate (CaCO3).

"Intake credit" is a procedure for establishing effluent limits 

in waste discharge permits issued pursuant to the National Pollutant 

Discharge Elimination System that take into account the amount of a 

pollutant that is present in public waters, at the time water is removed from the body of water by the discharger or other facility supplying the discharger with intake water.

"Irrigation ditch" means that portion of a designed and constructed conveyance system that serves the purpose of transporting irrigation water from its supply source to its place of use; this may include natural water courses or channels incorporated in the system design, but does not include the area adjacent to the water course or 

channel.

"Lakes" shall be distinguished from riverine systems as being water bodies, including reservoirs, with a mean detention time of greater than fifteen days.

"Lake-specific study" means a study intended to quantify existing 

nutrient concentrations, determine existing characteristic uses for 

lake class waters, and potential lake uses. The study determines how 

to protect these uses and if any uses are lost or impaired because of 

nutrients, algae, or aquatic plants. An appropriate study must recommend a criterion for total phosphorus (TP), total nitrogen (TN) in 

μg/l, or other nutrient that impairs characteristic uses by causing 

excessive algae blooms or aquatic plant growth.

"Mean detention time" means the time obtained by dividing a reservoir's mean annual minimum total storage by the thirty-day ten-year 

low-flow from the reservoir.

"Migration or translocation" means any natural movement of an organism or community of organisms from one locality to another locality.

"Mixing zone" means that portion of a water body adjacent to an 

effluent outfall where mixing results in the dilution of the effluent 

[ 3 ] OTS-6831.2
with the receiving water. Water quality criteria may be exceeded in a 

mixing zone as conditioned and provided for in WAC 173-201A-400.

"Natural conditions" or "natural background levels" means surface 

water quality that was present before any human-caused pollution. When 

estimating natural conditions in the headwaters of a disturbed watershed it may be necessary to use the less disturbed conditions of a 

neighboring or similar watershed as a reference condition. (See also 

WAC 173-201A-260(1).)

"New or expanded actions" mean human actions that occur or are 

regulated for the first time, or human actions expanded such that they 

result in an increase in pollution, after July 1, 2003, for the purpose of applying this chapter only.

"Nonpoint source" means pollution that enters any waters of the 

state from any dispersed land-based or water-based activities including, but not limited to, atmospheric deposition; surface water runoff 

from agricultural lands, urban areas, or forest lands; subsurface or 

underground sources; or discharges from boats or marine vessels not 

otherwise regulated under the National Pollutant Discharge Elimination 

System program.

"Permit" means a document issued pursuant to chapter 90.48 RCW 

specifying the waste treatment and control requirements and waste discharge conditions.

"pH" means the negative logarithm of the hydrogen ion concentration.

"Pollution" means such contamination, or other alteration of the 

physical, chemical, or biological properties, of any waters of the 

state, including change in temperature, taste, color, turbidity, or 

odor of the waters, or such discharge of any liquid, gaseous, solid, 

radioactive, or other substance into any waters of the state as will 

or is likely to create a nuisance or render such waters harmful, detrimental, or injurious to the public health, safety, or welfare, or to 

domestic, commercial, industrial, agricultural, recreational, or other 

legitimate beneficial uses, or to livestock, wild animals, birds, 

fish, or other aquatic life.

"Primary contact recreation" means activities where a person 

would have direct contact with water to the point of complete submergence including, but not limited to, skin diving, swimming, and water 

skiing.

"Secondary contact recreation" means activities where a person's 

water contact would be limited (e.g., wading or fishing) to the extent 

that bacterial infections of eyes, ears, respiratory or digestive systems, or urogenital areas would normally be avoided.

"Shoreline stabilization" means the anchoring of soil at the water's edge, or in shallow water, by fibrous plant root complexes; this 

may include long-term accretion of sediment or peat, along with shoreline progradation in such areas.

"Storm water" means that portion of precipitation that does not 

naturally percolate into the ground or evaporate, but flows via overland flow, interflow, pipes, and other features of a storm water 

drainage system into a defined surface water body, or a constructed 

infiltration facility.

"Storm water attenuation" means the process by which peak flows 

from precipitation are reduced and runoff velocities are slowed as a 

result of passing through a surface water body.

"Surface waters of the state" includes lakes, rivers, ponds, 

streams, inland waters, saltwaters, wetlands and all other surface wa­

[ 4 ] OTS-6831.2
ters and water courses within the jurisdiction of the state of Washington.

"Temperature" means water temperature expressed in degrees Celsius (°C).

"Treatment wetlands" means those wetlands intentionally constructed on nonwetland sites and managed for the primary purpose of wastewater or storm water treatment. Treatment wetlands are considered part 

of a collection and treatment system, and generally are not subject to 

the criteria of this chapter.

"Trophic state" means a classification of the productivity of a 

lake ecosystem. Lake productivity depends on the amount of biologically available nutrients in water and sediments and may be based on total phosphorus (TP). Secchi depth and chlorophyll-a measurements may 

be used to improve the trophic state classification of a lake. Trophic 

states used in this rule include, from least to most nutrient rich, 

ultra-oligotrophic, oligotrophic, lower mesotrophic, upper mesotrophic, and eutrophic.

"Turbidity" means the clarity of water expressed as nephelometric 

turbidity units (NTU) and measured with a calibrated turbidimeter.

"Upwelling" means the natural process along Washington's Pacific 

Coast where the summer prevailing northerly winds produce a seaward 

transport of surface water. Cold, deeper more saline waters rich in 

nutrients and low in dissolved oxygen, rise to replace the surface water. The cold oxygen deficient water enters Puget Sound and other 

coastal estuaries at depth where it displaces the existing deep water 

and eventually rises to replace the surface water. Such surface water 

replacement results in an overall increase in salinity and nutrients 

accompanied by a depression in dissolved oxygen. Localized upwelling 

of the deeper water of Puget Sound can occur year-round under influence of tidal currents, winds, and geomorphic features.

"USEPA" means the United States Environmental Protection Agency.

"Variance" is a temporary modification to the designated use and 

associated water quality criteria based on the factors specified in 40 

C.F.R. 131.10(g), and must be adopted by rule.

"Wetlands" means areas that are inundated or saturated by surface 

water or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of 

vegetation typically adapted for life in saturated soil conditions. 

Wetlands generally include swamps, marshes, bogs, and similar areas. 

Wetlands do not include those artificial wetlands intentionally created from nonwetland sites((,)) including, but not limited to, irrigation and drainage ditches, grass-lined swales, canals, detention facilities, wastewater treatment facilities, farm ponds, and landscape 

amenities, or those wetlands created after July 1, 1990, that were unintentionally created as a result of the construction of a road, 

street, or highway. Wetlands may include those artificial wetlands intentionally created from nonwetland areas to mitigate the conversion 

of wetlands. (Water bodies not included in the definition of wetlands 

as well as those mentioned in the definition are still waters of the 

state.)

"Wildlife habitat" means waters of the state used by, or that directly or indirectly provide food support to, fish, other aquatic 

life, and wildlife for any life history stage or activity.

[ 5 ] OTS-6831.2
AMENDATORY SECTION (Amending WSR 11-09-090, filed 4/20/11, effective 

5/21/11)

WAC 173-201A-240 Toxic substances. (1) Toxic substances shall 

not be introduced above natural background levels in waters of the 

state which have the potential either singularly or cumulatively to 

adversely affect characteristic water uses, cause acute or chronic 

toxicity to the most sensitive biota dependent upon those waters, or 

adversely affect public health, as determined by the department.

(2) The department shall employ or require chemical testing, 

acute and chronic toxicity testing, and biological assessments, as appropriate, to evaluate compliance with subsection (1) of this section 

and to ensure that aquatic communities and the existing and designated 

uses of waters are being fully protected.

(3) USEPA Quality Criteria for Water, 1986, as revised, shall be 

used in the use and interpretation of the values listed in subsection 

(5) of this section.

(4) Concentrations of toxic, and other substances with toxic propensities not listed in Table 240 of this section shall be determined 

in consideration of USEPA Quality Criteria for Water, 1986, and as revised, and other relevant information as appropriate.

(5) The following criteria, found in Table 240(((3))), shall be 

applied to all surface waters of the state of Washington ((for the 

protection of aquatic life)). Values are μg/L for all substances except ammonia and chloride which are mg/L, and asbestos which is million fibers/L.

(a) Aquatic life protection. The department may revise the following criteria in Table 240 for aquatic life on a statewide or water 

body-specific basis as needed to protect aquatic life occurring in waters of the state and to increase the technical accuracy of the criteria being applied. The department shall formally adopt any appropriate 

revised criteria as part of this chapter in accordance with the provisions established in chapter 34.05 RCW, the Administrative Procedure 

Act. The department shall ensure there are early opportunities for 

public review and comment on proposals to develop revised criteria. 

((Values are μg/L for all substances except Ammonia and Chloride which 

are mg/L:))

(b) Human health protection. The following provisions apply to 

the human health criteria in Table 240. All waters shall maintain a 

level of water quality when entering downstream waters that provides 

for the attainment and maintenance of the water quality standards of 

those downstream waters, including the waters of another state. The 

human health criteria in the tables were calculated using a fish consumption rate of 175 g/day. The human health criteria calculations and 

variables include chronic durations of exposure up to seventy years. 

All human health criteria for metals are for total metal concentrations, unless otherwise noted. Dischargers have the obligation to reduce toxics in discharges through the use of AKART.

Table 240(((3)))

Toxics Substances Criteria

((Substance

Freshwater Marine Water

Acute Chronic Acute Chronic

Aldrin/Dieldrin e 2.5a 0.0019b 0.71a 0.0019b

Ammonia (un-ionized NH3) hh f,c g,d 0.233h,c 0.035h,d

[ 6 ] OTS-6831.2
((Substance

Freshwater Marine Water

Acute Chronic Acute Chronic

Arsenic dd 360.0c 190.0d 69.0c,ll 36.0d,cc,ll

Cadmium dd i,c j,d 42.0c 9.3d

Chlordane 2.4a 0.0043b 0.09a 0.004b

Chloride (Dissolved) k 860.0h,c 230.0h,d - -

Chlorine (Total Residual) 19.0c 11.0d 13.0c 7.5d

Chlorpyrifos 0.083c 0.041d 0.011c 0.0056d

Chromium (Hex) dd 15.0c,l,ii 10.0d,jj 1,100.0c,l,ll 50.0d,ll

Chromium (Tri) gg m,c n,d - -

Copper dd o,c p,d 4.8c,ll 3.1d,ll

Cyanide ee 22.0c 5.2d 1.0c,mm d,mm

DDT (and metabolites) 1.1a 0.001b 0.13a 0.001b

Dieldrin/Aldrin e 2.5a 0.0019b 0.71a 0.0019b

Endosulfan 0.22a 0.056b 0.034a 0.0087b

Endrin 0.18a 0.0023b 0.037a 0.0023b

Heptachlor 0.52a 0.0038b 0.053a 0.0036b

Hexachlorocyclohexane (Lindane) 2.0a 0.08b 0.16a -

Lead dd q,c r,d 210.0c,ll 8.1d,ll

Mercury s 2.1c,kk,dd 0.012d,ff 1.8c,ll,dd 0.025d,ff

Nickel dd t,c u,d 74.0c,ll 8.2d,ll

Parathion 0.065c 0.013d - -

Pentachlorophenol (PCP) w,c v,d 13.0c 7.9d

Polychlorinated Biphenyls (PCBs) 2.0b 0.014b 10.0b 0.030b

Selenium 20.0c,ff 5.0d,ff 290c,ll,dd 71.0d,

x,ll,dd

Silver dd y,a - 1.9a,ll -

Toxaphene 0.73c,z 0.0002d 0.21c,z 0.0002d

Zinc dd aa,c bb,d 90.0c,ll 81.0d,ll

Notes to Table 240(3):))

Compound/Chemical

Chemical 

Abstracts 

Service

(CAS)# Category

Aquatic Life

Criteria - Freshwater

Aquatic Life Criteria - 

Marine Water

Human Health Criteria

for Consumption of:

Acute Chronic Acute Chronic

Water & 

Organisms

Organisms 

Only

Metals:

Antimony 7440360 Metals, cyanide,

and total phenols

14

(A)

180

Arsenic 7440382 Metals, cyanide,

and total phenols

360.0

(c,dd)

190.0

(d,dd)

69.0

(c,ll,dd)

36.0

(d,cc,ll,dd)

10

(B)

10

(B)

Asbestos 1332214 Toxic pollutants 

and

hazardous 

substances

7,000,000

fibers/L (D)

Beryllium 7440417 Metals, cyanide,

and total phenols

Cadmium 7440439 Metals, cyanide,

and total phenols

(I,c,dd) (I,c,dd) 42.0

(c,dd)

9.3

(d,dd)

Chromium (III) 16065831 Metals, cyanide,

and total phenols

(m,c,gg) (n,d,gg)

Chromium (VI) 18540299 Metals, cyanide,

and total phenols

15.0

(c,l,ii,dd)

10.0

(d,jj,dd)

1,100.0

(c,l,ll,dd)

50.0

(d,ll,dd)

Copper 7440508 Metals, cyanide,

and total phenols

(o,c,dd) (p,d,dd) 4.8

(c,ll,dd)

3.1

(d,ll,dd)

1,300

(D)

[ 7 ] OTS-6831.2
Compound/Chemical

Chemical 

Abstracts 

Service

(CAS)# Category

Aquatic Life

Criteria - Freshwater

Aquatic Life Criteria - 

Marine Water

Human Health Criteria

for Consumption of:

Acute Chronic Acute Chronic

Water & 

Organisms

Organisms 

Only

Lead 7439921 Metals, cyanide,

and total phenols

(q,c,dd) (r,d,dd) 210.0

(c,ll,dd)

8.1

(d,ll,dd)

Mercury 7439976 Metals, cyanide,

and total phenols

2.1

(c,kk,dd)

0.012

(d,ff,s)

1.8

(c,ll,dd)

0.025

(d,ff,s)

(H) (H)

Methylmercury 22967926 Nonconventional

Nickel 7440020 Metals, cyanide,

and total phenols

(t,c,dd) (u,d,dd) 74.0

(c,ll,dd)

8.2

(d,ll,dd)

160 190

Selenium 7782492 Metals, cyanide,

and total phenols

20.0

(c,ff)

5.0

(d,ff)

290

(c,ll,dd)

71.0

(d,x,ll,dd)

140 480

Silver 7440224 Metals, cyanide,

and total phenols

(y,a,dd) 1.9

(a,ll,dd)

Thallium 7440280 Metals, cyanide,

and total phenols

0.24 0.27

Zinc 7440666 Metals, cyanide,

and total phenols

(aa,c,dd) (bb,d,dd) 90.0

(c,ll,dd)

81.0

(d,ll,dd)

2,300 2,900

Other chemicals:

1,1,1-Trichloroethane 71556 Volatile

1,1,2,2-Tetrachloroethane 79345 Volatile 0.17

(A, C)

4.6

(C)

1,1,2-Trichloroethane 79005 Volatile 0.60

(A, C)

18

(C)

1,1-Dichloroethane 75343 Volatile

1,1-Dichloroethylene 75354 Volatile 0.057

(A)

3.2

(A)

1,2,4-Trichlorobenzene 120821 Base/neutral 

compounds

36 40

1,2-Dichlorobenzene 95501 Volatile 610 740

1,2-Dichloroethane 107062 Volatile 0.38

(A, C)

42

(C)

1,2-Dichloropropane 78875 Volatile 4.4

(C)

17

(C)

1,3-Dichloropropene 542756 Volatile 10

(A)

72

1,2-Diphenylhydrazine 122667 Base/neutral 

compounds

0.040

(A, C)

0.23

(C)

1,2-Trans-Dichloroethylene 156605 Volatile 700 5,800

1,3-Dichlorobenzene 541731 Volatile 91 110

1,4-Dichlorobenzene 106467 Volatile 91 110

2,3,7,8-TCDD (Dioxin) 1746016 Dioxin 0.000000013

(A)

0.000000014

(A)

2,4,6-Trichlorophenol 88062 Acid compounds 2.1

(A, C)

2.8

(C)

2,4-Dichlorophenol 120832 Acid compounds 26 34

2,4-Dimethylphenol 105679 Acid compounds 87 97

2,4-Dinitrophenol 51285 Acid compounds 70

(A)

610

2,4-Dinitrotoluene 121142 Base/neutral 

compounds

0.11

(A, C)

3.9

(C)

2,6-Dinitrotoluene 606202 Base/neutral 

compounds

2-Chloroethyvinyl Ether 110758 Volatile

2-Chloronaphthalene 91587 Base/neutral 

compounds

170 180

2-Chlorophenol 95578 Acid compounds 16 17

2-Methyl-4,6-Dinitrophenol

(4,6-dinitro-o-cresol)

534521 Acid compounds 11 32

2-Nitrophenol 88755 Acid compounds

3,3'-Dichlorobenzidine 91941 Base/neutral 

compounds

0.031

(C)

0.033

(C)

[ 8 ] OTS-6831.2
Compound/Chemical

Chemical 

Abstracts 

Service

(CAS)# Category

Aquatic Life

Criteria - Freshwater

Aquatic Life Criteria - 

Marine Water

Human Health Criteria

for Consumption of:

Acute Chronic Acute Chronic

Water & 

Organisms

Organisms 

Only

3-Methyl-4-Chlorophenol 

(parachlorometa cresol)

59507 Acid compounds

4,4'-DDD 72548 Pesticides/PCBs 0.00036

(C)

0.00036

(C)

4,4'-DDE 72559 Pesticides/PCBs 0.00025

(C)

0.00025

(C)

4,4'-DDT 50293 Pesticides/PCBs 0.00025

(C)

0.00025

(C)

4,4'-DDT(and metabolites) Pesticides/PCBs 1.1

(a)

0.001

(b)

0.13

(a)

0.001

(b)

4-Bromophenyl

Phenyl Ether

101553 Base/neutral 

compounds

4-Chorophenyl Phenyl 

Ether

7005723 Base/neutral 

compounds

4-Nitrophenol 100027 Acid compounds

Acenaphthene 83329 Base/neutral 

compounds

110 110

Acenaphthylene 208968 Base/neutral 

compounds

Acrolein 107028 Volatile 1.0 1.1

Acrylonitrile 107131 Volatile 0.059

(A, C)

0.28

(C)

Aldrin 309002 Pesticides/PCBs 2.5

(a,e)

0.0019

(b,e)

0.71

(a,e)

0.0019

(b,e)

0.000057

(C)

0.000058

(C)

alpha-BHC 319846 Pesticides/PCBs 0.0039

(A, C)

0.0056

(C)

alpha-Endosulfan 959988 Pesticides/PCBs 0.93

(A)

2.0

(A)

Anthracene 120127 Base/neutral 

compounds

3,300 4,600

Benzene 71432 Volatile 1.2

(A, C)

59

(C)

Benzidine 92875 Base/neutral 

compounds

0.00012

(A, C)

0.00023

(C)

Benzo(a) Anthracene 56553 Base/neutral 

compounds

0.0028

(A, C)

0.021

(C)

Benzo(a) Pyrene 50328 Base/neutral 

compounds

0.0028

(A, C)

0.021

(C)

Benzo(b) Fluoranthene 205992 Base/neutral 

compounds

0.0028

(A, C)

0.021

(C)

Benzo(ghi) Perylene 191242 Base/neutral 

compounds

Benzo(k) Fluoranthene 207089 Base/neutral 

compounds

0.0028

(A, C)

0.021

(C)

beta-BHC 319857 Pesticides/PCBs 0.014

(A, C)

0.020

(C)

beta-Endosulfan 33213659 Pesticides/PCBs 0.93

(A)

2.0

(A)

Bis(2-Chloroethoxy)

Methane

111911 Base/neutral 

compounds

Bis(2-Chloroethyl) Ether 111444 Base/neutral 

compounds

0.031

(A, C)

0.60

(C)

Bis(2-Chloroisopropyl)

Ether

108601 Base/neutral 

compounds

1,300 7,400

Bis(2-Ethylhexyl) Phthalate 117817 Base/neutral 

compounds

1.8

(A, C)

2.5

(C)

Bromoform 75252 Volatile 4.3

(A, C)

150

(C)

Butylbenzyl Phthalate 85687 Base/neutral 

compounds

210 220

Carbon Tetrachloride 56235 Volatile 0.25

(A, C)

1.9

(C)

[ 9 ] OTS-6831.2
Compound/Chemical

Chemical 

Abstracts 

Service

(CAS)# Category

Aquatic Life

Criteria - Freshwater

Aquatic Life Criteria - 

Marine Water

Human Health Criteria

for Consumption of:

Acute Chronic Acute Chronic

Water & 

Organisms

Organisms 

Only

Chlordane 57749 Pesticides/PCBs 2.4

(a)

0.0043

(b)

0.09

(a)

0.004

(b)

0.00057

(A, C)

0.00059

(A, C)

Chlorobenzene 108907 Volatile 420 890

Chlorodibromomethane 124481 Volatile 0.41

(A, C)

15

(C)

Chloroethane 75003 Volatile

Chloroform 67663 Volatile 5.7

(A)

470

(A)

Chrysene 218019 Base/neutral 

compounds

0.0028

(A, C)

0.021

(C)

Cyanide 57125 Metals, cyanide,

and total phenols

22.0

(c,ee)

5.2

(d,ee)

1.0

(c,mm,ee)

(d,mm,ee) 700

(A, E)

9,100

(E)

delta-BHC 319868 Pesticides/PCBs

Dibenzo(a,h) Anthracene 53703 Base/neutral 

compounds

0.0028

(A, C)

0.021

(C)

Dichlorobromomethane 75274 Volatile 0.27

(A, C)

20

(C)

Dieldrin 60571 Pesticides/PCBs 2.5

(a,e)

0.0019

(b,e)

0.71

(a,e)

0.0019

(b,e)

0.000061

(C)

0.000061

(C)

Diethyl Phthalate 84662 Base/neutral 

compounds

4,300 5,000

Dimethyl Phthalate 131113 Base/neutral 

compounds

96,000 130,000

Di-n-Butyl Phthalate 84742 Base/neutral 

compounds

460 510

Di-n-Octyl Phthalate 117840 Base/neutral 

compounds

Endosulfan Pesticides/PCBs 0.22

(a)

0.056

(b)

0.034

(a)

0.0087

(b)

Endosulfan Sulfate 1031078 Pesticides/PCBs 0.93

(A)

2.0

(A)

Endrin 72208 Pesticides/PCBs 0.18

(a)

0.0023

(b)

0.037

(a)

0.0023

(b)

0.034 0.035

Endrin Aldehyde 7421934 Pesticides/PCBs 0.034 0.035

Ethylbenzene 100414 Volatile 930 1,200

Fluoranthene 206440 Base/neutral 

compounds

16 16

Fluorene 86737 Base/neutral 

compounds

440 610

Hexachlorocyclohexane

(gamma-BHC; Lindane)

58899 Pesticides/PCBs 2.0

(a)

0.08

(b)

0.16

(a)

0.019

(A)

0.063

(A)

Heptachlor 76448 Pesticides/PCBs 0.52

(a)

0.0038

(b)

0.053

(a)

0.0036

(b)

0.000091

(C)

0.000091

(C)

Heptachlor Epoxide 1024573 Pesticides/PCBs 0.000045

(C)

0.000045

(C)

Hexachlorobenzene 118741 Base/neutral 

compounds

0.00033

(C)

0.00033

(C)

Hexachlorobutadiene 87683 Base/neutral 

compounds

0.44

(A, C)

21

(C)

Hexachlorocyclopentadiene 77474 Base/neutral 

compounds

170 630

Hexachloroethane 67721 Base/neutral 

compounds

1.9

(A, C)

3.8

(C)

Indeno(1,2,3-cd) Pyrene 193395 Base/neutral 

compounds

0.0028

(A, C)

0.021

(C)

Isophorone 78591 Base/neutral 

compounds

8.4

(A, C)

600

(A, C)

Methyl Bromide 74839 Volatile 42 170

Methyl Chloride 74873 Volatile

Methylene Chloride 75092 Volatile 4.7

(A, C)

680

(C)

[ 10 ] OTS-6831.2
Compound/Chemical

Chemical 

Abstracts 

Service

(CAS)# Category

Aquatic Life

Criteria - Freshwater

Aquatic Life Criteria - 

Marine Water

Human Health Criteria

for Consumption of:

Acute Chronic Acute Chronic

Water & 

Organisms

Organisms 

Only

Napthalene 91203 Base/neutral 

compounds

Nitrobenzene 98953 Base/neutral 

compounds

16 79

N-Nitrosodimethylamine 62759 Base/neutral 

compounds

0.00069

(A, C)

3.4

(C)

N-Nitrosodi-n-Propylamine 621647 Base/neutral 

compounds

0.052

(C)

0.58

(C)

N-Nitrosodiphenylamine 86306 Base/neutral 

compounds

5.0

(A, C)

6.9

(C)

Pentachlorophenol (PCP) 87865 Acid compounds (w,c) (v,d) 13.0

(c)

7.9

(d)

0.28

(A, C)

3.5

(C)

Phenanthrene 85018 Base/neutral 

compounds

Phenol 108952 Acid compounds 11,000 98,000

Polychlorinated Biphenyls 

(PCBs)

Pesticides/PCBs 2.0

(b)

0.014

(b)

10.0

(b)

0.030

(b)

0.00017

(A, F)

0.00017

(A, F)

Pyrene 129000 Base/neutral 

compounds

330 460

Tetrachloroethylene 127184 Volatile 0.8

(A, C)

3.8

(C)

Toluene 108883 Volatile 4,100 8,500

Toxaphene 8001352 Pesticides/PCBs 0.73

(c,z)

0.0002

(d)

0.21

(c,z)

0.0002

(d)

0.00032

(C)

0.00032

(C)

Trichloroethylene 79016 Volatile 2.7

(A, C)

34

(C)

Vinyl Chloride 75014 Volatile 0.26

(C, G)

2.8

(C, G)

Ammonia (hh) Nonconventional (f,c) (g,d) 0.233

(h,c)

0.035

(h,d)

Chloride (dissolved) (k) Nonconventional 860.0

(h,c)

230.0

(h,d)

Chlorine (total residual) Nonconventional 19.0

(c)

11.0

(d)

13.0

(c)

7.5

(d)

Chlorpyrifos Toxic pollutants 

and

hazardous 

substances

0.083

(c)

0.041

(d)

0.011

(c)

0.0056

(d)

Parathion Toxic pollutants 

and

hazardous 

substances

0.065

(c)

0.013

(d)

Footnotes for aquatic life criteria in Table 240:

a. An instantaneous concentration not to be exceeded at any time.

b. A 24-hour average not to be exceeded.

c. A 1-hour average concentration not to be exceeded more than once every three years on the average.

d. A 4-day average concentration not to be exceeded more than once every three years on the average.

e. Aldrin is metabolically converted to Dieldrin. Therefore, the sum of the Aldrin and Dieldrin concentrations are compared with the Dieldrin 

criteria.

f. Shall not exceed the numerical value in total ammonia nitrogen (mg N/L) given by:

For salmonids present: 0.275

+

39.0

1 + 107.204-pH 1 + 10pH-7.204

For salmonids absent: 0.411

+

58.4

1 + 107.204-pH 1 + 10pH-7.204

g. Shall not exceed the numerical concentration calculated as follows:

Unionized ammonia concentration for waters where salmonid habitat is an existing or designated use:

0.80 ÷ (FT)(FPH)(RATIO)

where: RATIO = 13.5; 7.7 ≤ pH ≤ 9

RATIO = (20.25 x 10(7.7-pH)) ÷ (1 + 10(7.4-pH)); 6.5 ≤ pH ≤

7.7

[ 11 ] OTS-6831.2
FT = 1.4; 15 ≤ T ≤ 30

FT = 10[0.03(20-T)]; 0 ≤ T ≤ 15

FPH = 1; 8 ≤ pH ≤ 9

FPH = (1 + 10(7.4-pH)) ÷ 1.25; 6.5 ≤ pH ≤ 8.0

Total ammonia concentrations for waters where salmonid habitat is not an existing or designated 

use and other fish early life stages are absent:

where: A = the greater of either T (temperature in degrees Celsius) 

or 7.

Applied as a thirty-day average concentration of total ammonia nitrogen (in mg N/L) not to be exceeded more than once every three years on average. The highest four-day average within the thirty-day period should not exceed 2.5 times the chronic criterion.

Total ammonia concentration for waters where salmonid habitat is not an existing or designated use 

and other fish early life stages are present:

where: B = the lower of either 2.85, or 1.45 x 100.028 x (25-T). T = temperature in degrees Celsius.

Applied as a thirty-day average concentration of total ammonia nitrogen (in mg N/L) not to be exceeded more than once every three years 

on the average. The highest four-day average within the thirty-day period should not exceed 2.5 times the chronic criterion.

h. Measured in milligrams per liter rather than micrograms per liter.

i. ≤ (0.944)(e(1.128[ln(hardness)]-3.828)) at hardness = 100. Conversion factor (CF) of 0.944 is hardness dependent. CF is calculated for 

other hardnesses as follows: CF = 1.136672 - [(ln hardness)(0.041838)].

j. ≤ (0.909)(e(0.7852[ln(hardness)]-3.490)) at hardness = 100. Conversions factor (CF) of 0.909 is hardness dependent. CF is calculated for 

other hardnesses as follows: CF = 1.101672 - [(ln hardness)(0.041838)].

k. Criterion based on dissolved chloride in association with sodium. This criterion probably will not be adequately protective when the 

chloride is associated with potassium, calcium, or magnesium, rather than sodium.

l. Salinity dependent effects. At low salinity the 1-hour average may not be sufficiently protective.

m. ≤ (0.316)(e(0.8190[ ln(hardness)] + 3.688))

n. ≤ (0.860)(e(0.8190[ ln(hardness)] + 1.561))

o. ≤ (0.960)(e(0.9422[ ln(hardness)] - 1.464))

p. ≤ (0.960)(e(0.8545[ ln(hardness)] - 1.465))

q. ≤ (0.791)(e(1.273[ ln(hardness)] - 1.460)) at hardness = 100. Conversion factor (CF) of 0.791 is hardness dependent. CF is calculated for other 

hardnesses as follows: CF = 1.46203 - [(ln hardness)(0.145712)].

r. ≤ (0.791)(e(1.273[ ln(hardness)] - 4.705)) at hardness = 100. Conversion factor (CF) of 0.791 is hardness dependent. CF is calculated for other 

hardnesses as follows: CF = 1.46203 - [(ln hardness)(0.145712)].

s. If the four-day average chronic concentration is exceeded more than once in a three-year period, the edible portion of the consumed species 

should be analyzed. Said edible tissue concentrations shall not be allowed to exceed 1.0 mg/kg of methylmercury.

t. ≤ (0.998)(e(0.8460[ ln(hardness)] + 3.3612))

u. ≤ (0.997)(e(0.8460[ ln(hardness)] + 1.1645))

v. ≤ e[1.005(pH) - 5.290]

w. ≤ e[1.005(pH) - 4.830]

x. The status of the fish community should be monitored whenever the concentration of selenium exceeds 5.0 ug/ l in salt water.

y. ≤ (0.85)(e(1.72[ln(hardness)] - 6.52))

z. Channel Catfish may be more acutely sensitive.

aa. ≤ (0.978)(e(0.8473[ln(hardness)] + 0.8604))

bb. ≤ (0.986)(e(0.8473[ln(hardness)] + 0.7614))

cc. Nonlethal effects (growth, C-14 uptake, and chlorophyll production) to diatoms (Thalassiosira aestivalis and Skeletonema costatum) which 

are common to Washington's waters have been noted at levels below the established criteria. The importance of these effects to the diatom 

populations and the aquatic system is sufficiently in question to persuade the state to adopt the USEPA National Criteria value (36 μg/L) as 

the state threshold criteria, however, wherever practical the ambient concentrations should not be allowed to exceed a chronic marine 

concentration of 21 μg/L.

dd. These ambient criteria in the table are for the dissolved fraction. The cyanide criteria are based on the weak acid dissociable method. The 

metals criteria may not be used to calculate total recoverable effluent limits unless the seasonal partitioning of the dissolved to total metals 

in the ambient water are known. When this information is absent, these metals criteria shall be applied as total recoverable values, 

determined by back-calculation, using the conversion factors incorporated in the criterion equations. Metals criteria may be adjusted on a 

site-specific basis when data are made available to the department clearly demonstrating the effective use of the water effects ratio approach 

established by USEPA, as generally guided by the procedures in USEPA Water Quality Standards Handbook, December 1983, as 

supplemented or replaced by USEPA or ecology. Information which is used to develop effluent limits based on applying metals partitioning 

studies or the water effects ratio approach shall be identified in the permit fact sheet developed pursuant to WAC 173-220-060 or 

173-226-110, as appropriate, and shall be made available for the public comment period required pursuant to WAC 173-220-050 or 

173-226-130(3), as appropriate. Ecology has developed supplemental guidance for conducting water effect ratio studies.

ee. The criteria for cyanide is based on the weak acid dissociable method in the 19th Ed. Standard Methods for the Examination of Water and 

Wastewater, 4500-CN I, and as revised (see footnote dd, above).

ff. These criteria are based on the total-recoverable fraction of the metal.

gg. Where methods to measure trivalent chromium are unavailable, these criteria are to be represented by total-recoverable chromium.

hh. The listed fresh water criteria are based on un-ionized or total ammonia concentrations, while those for marine water are based on unionized ammonia concentrations. Tables for the conversion of total ammonia to un-ionized ammonia for freshwater can be found in the 

USEPA's Quality Criteria for Water, 1986. Criteria concentrations based on total ammonia for marine water can be found in USEPA 

Ambient Water Quality Criteria for Ammonia (Saltwater)-1989, EPA440/5-88-004, April 1989.

[ 12 ] OTS-6831.2
ii. The conversion factor used to calculate the dissolved metal concentration was 0.982.

jj. The conversion factor used to calculate the dissolved metal concentration was 0.962.

kk. The conversion factor used to calculate the dissolved metal concentration was 0.85.

ll. Marine conversion factors (CF) which were used for calculating dissolved metals concentrations are given below. Conversion factors are 

applicable to both acute and chronic criteria for all metals except mercury. The CF for mercury was applied to the acute criterion only and is 

not applicable to the chronic criterion. Conversion factors are already incorporated into the criteria in the table. Dissolved criterion = 

criterion x CF

Metal CF

Arsenic 1.000

Cadmium 0.994

Chromium (VI) 0.993

Copper 0.83

Lead 0.951

Mercury 0.85

Nickel 0.990

Selenium 0.998

Silver 0.85

Zinc 0.946

mm. The cyanide criteria are: 2.8μg/l chronic and 9.1μg/l acute and are applicable only to waters which are east of a line from Point Roberts to 

Lawrence Point, to Green Point to Deception Pass; and south from Deception Pass and of a line from Partridge Point to Point Wilson. The 

chronic criterion applicable to the remainder of the marine waters is l μg/L.

(((4) USEPA Quality Criteria for Water, 1986, as revised, shall 

be used in the use and interpretation of the values listed in subsection (3) of this section.

(5) Concentrations of toxic, and other substances with toxic propensities not listed in subsection (3) of this section shall be determined in consideration of USEPA Quality Criteria for Water, 1986, and 

as revised, and other relevant information as appropriate. Human 

health-based water quality criteria used by the state are contained in 

40 C.F.R. 131.36 (known as the National Toxics Rule).

(6) Risk-based criteria for carcinogenic substances shall be selected such that the upper-bound excess cancer risk is less than or 

equal to one in one million.))

Footnotes for human health criteria in Table 240:

A. The value for this chemical was originally calculated based on cancer or noncancer risk, but because that calculation resulted in a higher concentration 

than that found in 40 C.F.R. 131.36, the criterion defaulted to the concentration found in 40 C.F.R. 131.36.

B. This criterion for total arsenic is the maximum contaminant level (MCL) developed under the Safe Drinking Water Act. The MCL for total arsenic is 

applied to surface waters where consumption of organisms-only and where consumption of water + organisms reflect the designated uses. When the 

department determines that a direct or indirect industrial discharge to surface waters designated for domestic water supply may be adding arsenic to its 

wastewater, the department will require the discharger to develop and implement a pollution prevention plan to reduce arsenic through the use of 

AKART. Industrial wastewater discharges to a privately or publicly owned wastewater treatment facility are considered indirect discharges.

C. This criterion was calculated based on an additional lifetime cancer risk of one in one hundred thousand (1 x 10-5 risk level). For some chemicals the 

criterion value defaulted from the risk-based concentration to the 40 C.F.R. 131.36 concentration, as indicated in footnote A. In these cases the 

additional lifetime cancer risk associated with the criterion is less than one in one hundred thousand.

D. This criterion is based on a regulatory level developed under the Safe Drinking Water Act.

E. This recommended water quality criterion is expressed as total cyanide, even though the integrated risk information system RfD used to derive the 

criterion is based on free cyanide. The multiple forms of cyanide that are present in ambient water have significant differences in toxicity due to their 

differing abilities to liberate the CN-moiety. Some complex cyanides require even more extreme conditions than refluxing with sulfuric acid to liberate 

the CN-moiety. Thus, these complex cyanides are expected to have little or no "bioavailability" to humans. If a substantial fraction of the cyanide 

present in a water body is present in a complexed form (e.g., Fe4[Fe(CN)6]3), this criterion may be overly conservative.

F. This criterion applies to total PCBs, (e.g., the sum of all congener or all isomer or homolog or Aroclor analyses). The PCBs criteria were calculated 

using a 4 x 10-5 risk level, but because that calculation resulted in a higher concentration than that found in 40 C.F.R. 131.36, the criterion concentration 

defaulted to the concentration found in 40 C.F.R. 131.36, as indicated in footnote A.

G. This criterion was derived using the cancer slope factor of 1.4 (linearized multistage model with a twofold increase to 1.4 per mg/kg-day to account for 

continuous lifetime exposure from birth).

H. The human health criteria for mercury are contained in 40 C.F.R. 131.36.

AMENDATORY SECTION (Amending WSR 11-09-090, filed 4/20/11, effective 

5/21/11)

WAC 173-201A-420 Variance. (((1) The criteria established in 

WAC 173-201A-200 through 173-201A-260 and 173-201A-600 through 

173-201A-612 may be modified for individual facilities, or stretches 

[ 13 ] OTS-6831.2
of waters, through the use of a variance. Variances may be approved by 

the department when:

(a) The modification is consistent with the requirements of federal law (currently 40 C.F.R. 131.10(g) and 131.10(h));

(b) The water body is assigned variances for specific criteria 

and all other applicable criteria must be met; and

(c) Reasonable progress is being made toward meeting the original 

criteria.

(2) The decision to approve a variance is subject to a public and 

intergovernmental involvement process.

(3) The department may issue a variance for up to five years, and 

may renew the variance after providing for another opportunity for 

public and intergovernmental involvement and review.

(4) Variances are not in effect until they have been incorporated 

into this chapter and approved by the USEPA.)) (1) General provisions. 

The criteria established in WAC 173-201A-200 through 173-201A-260 and 

173-201A-600 through 173-201A-612 may be modified for individual facilities, a group of facilities, or stretches of waters, through the 

use of a variance. The following conditions apply when considering issuance of a variance:

(a) A variance may be considered when the standards are expected 

to be attained by the end of the variance period or the attainable use 

cannot be reliably determined.

(b) The variance applies to specific parameters and all other applicable standards remain in effect for the water body.

(c) The modification must be consistent with the requirements of 

federal regulations (currently 40 C.F.R. 131.10).

(d) Reasonable progress must be made toward meeting the original 

standards during the variance period.

(e) A variance renewal may be considered if the renewal request 

meets the above conditions.

(2) Types of variances. Upon request or on its own initiative, 

the department will consider granting the following types of variances 

to existing water quality standards:

(a) An individual variance is a designated use and parameter-specific change to the standard(s) of the receiving water body for a specific discharger. The temporary standard(s) only apply at the point(s) 

of compliance for the individual facility.

(b) A multidischarger variance is a designated use and parameterspecific change to the standard(s) of any water body that receives 

discharges from a permitted facility defined within the scope of the 

multidischarger variance. Any permitted discharger that is defined 

within the scope of the variance may be covered under the variance 

that is granted by the department, provided all requirements of the 

variance for that discharger are met.

(c) A water body variance is a designated use and parameter-specific change to the standard(s) for a stretch of waters. Any discharger of the specific parameter that is defined within the geographic 

scope of the water body variance may be covered under the variance 

that is granted by the department, provided all requirements of the 

variance for that discharger are met.

(3) Requirements. Any entity initiating a variance request or applying for coverage for an individual, multidischarger, or water body 

variance must submit the following information to the department:

(a) The pollutant(s) and designated use(s) proposed to be modified by the variance, and the proposed duration of the variance.

[ 14 ] OTS-6831.2
(b) A demonstration that attaining the water quality standard for 

a specific pollutant is not feasible for the requested duration of the 

variance based on one or more of the conditions found in 40 C.F.R. 

131.10.

(c) An evaluation of treatment or alternative actions that were 

considered to meet effluent limits based on the original water quality 

criteria, and a description of why these options are not technically, 

economically, or otherwise feasible.

(d) Sufficient water quality data and analyses to characterize 

receiving and discharge water pollutant concentrations.

(e) A description and schedule of actions that the discharger(s) 

proposes to ensure the original water quality standard(s) are met or 

the highest attainable use is attained within the variance period. 

Dischargers are also required to submit a schedule for development and 

implementation of a pollutant minimization plan for the subject pollutant(s).

(f) If the variance is for a water body or stretch of water, the 

following information must also be provided to the department:

(i) The results from a pollutant source assessment that quantifies the contribution of pollution from permitted sources and nonpermitted sources;

(ii) All cost-effective and reasonable best management practices 

for permitted sources that address the pollutant the variance is based 

upon; and

(iii) Best management practices for nonpermitted sources that 

meet the requirements of chapter 90.48 RCW.

(g) Any additional information the department deems necessary to 

evaluate the application.

(4) Public review and notification. The decision to grant a variance is a formal rule making subject to a public and intergovernmental involvement process.

(a) The department will provide notice of the proposed variance 

and consult with Indian tribes or other states that have jurisdiction 

over adjacent and downstream waters of the proposed variance.

(b) The department shall maintain and make publicly available a 

list of dischargers that are covered under the variances that are in 

effect.

(5) Period during which the variance is in effect. A variance is 

a temporary modification to the designated use and associated water 

quality criteria.

(a) Each variance will be granted for the minimum time estimated 

to meet the original standard(s) or, if during the period of the variance it is determined that a designated use cannot be attained, then 

a use attainability analysis (WAC 173-201A-440) will be initiated.

(b) The ability to apply a variance in permits or other actions 

may be terminated by the department as a result of a mandatory interim 

review.

(c) Variances are in effect after they have been incorporated into this chapter and approved by the USEPA.

(6) Contents of a variance. At a minimum a variance adopted into 

rule will include the following:

(a) The time period for which the variance is applicable.

(b) The geographic area or specific waters in which the variance 

is applicable.

(c) A description of the permitted and unpermitted dischargers 

covered by the variance.

[ 15 ] OTS-6831.2
(d) Identification of required actions and a schedule, including 

any measurable milestones, for all pollution sources (permitted and 

unpermitted) subject to the variance. Dischargers are required to use 

adaptive management to fine tune and update actions, schedules, and 

milestones in order to achieve the goals of the variance.

(e) A provision allowing the department to reopen and modify any 

permits and to revise BMP requirements for unpermitted dischargers as 

a result of the mandatory interim review of the variance (see subsection (8) of this section).

(7) Variance permit conditions. The department must establish and 

incorporate into NPDES permits all conditions necessary to implement 

and enforce an approved variance, including:

(a) Effluent limits that represent currently achieved or achievable effluent conditions, or effluent limits that are sufficient to 

meet the original water quality standard upon expiration of the variance;

(b) Monitoring and reporting requirements; and

(c) A provision allowing the department to reopen and modify the 

permits based on the mandatory interim review of the variance.

(8) Mandatory interim review. The department will conduct an interim review of each variance at least once every five years after the 

variance is adopted and approved to determine that conditions of the 

variance are being met and to evaluate whether the variance is still 

necessary.

(a) Review process for individual discharger and multidischarger 

variances:

(i) The review shall be coordinated with the public review process of the permit renewal if the variance is being implemented in a 

permit.

(ii) The review will be focused on the discharger's compliance 

with permit conditions that are required by the variance as well as an 

evaluation of whether the variance is still necessary.

(b) Review process for water body variances:

(i) Variances for stretches of waters will be reviewed in a public process conducted by the department every five years after initial 

adoption of the variance into rule.

(ii) The review will evaluate whether the variance is still necessary, any new information on sources of the pollutant that indicates 

that reductions could be made that would allow water quality standards 

to be met in a shorter time frame, as well as any new information that 

indicates water quality improvements may require more time.

(c) A variance that applies to a permit will be shortened or terminated if the review determines that:

(i) The conditions and requirements of the variance and associated permit requirements have not been complied with unless reasons 

outside the control of the discharger prevented meeting any condition 

or requirement; or

(ii) Water quality standards could be met in a shorter time 

frame, based on new information submitted to the department.

NEW SECTION

WAC 173-201A-460 Intake credits. (1) General provisions. The 

following provisions apply to the consideration of intake credits in 

[ 16 ] OTS-6831.2
determining reasonable potential and establishing water quality based 

effluent limits (WQBELs) for waste discharge permits issued pursuant 

to the National Pollutant Discharge Elimination System.

(a) An "intake pollutant" is the amount of a pollutant that is 

present in public waters (including groundwater as provided in (d) of 

this subsection) at the time water is removed from the same body of 

water by the discharger or other facility supplying the discharger 

with intake water.

(b) An intake pollutant must be from the "same body of water" as 

the discharge in order to be eligible for an intake credit. An intake 

pollutant is considered to be from the "same body of water" as the 

discharge if the department finds that the intake pollutant would have 

reached the vicinity of the outfall point in the receiving water within a reasonable period had it not been removed by the permittee. This 

finding will be established if:

(i) The background concentration of the pollutant in the receiving water (excluding any amount of the pollutant in the facility's 

discharge) is similar to that in the intake water; and

(ii) There is a direct hydrological connection between the intake 

and discharge points.

(c) The department may also consider other site-specific factors 

relevant to the transport and fate of the pollutant to make the finding in a particular case that a pollutant would or would not have 

reached the vicinity of the outfall point in the receiving water within a reasonable period had it not been removed by the permittee.

(d) An intake pollutant from groundwater may be considered to be 

from the "same body of water" if the department determines that the 

pollutant would have reached the vicinity of the outfall point in the 

receiving water within a reasonable period had it not been removed by 

the permittee.

(2) Consideration of intake pollutants.

(a) The department may determine if there is reasonable potential 

for the discharge of an identified intake pollutant to cause or contribute to an exceedance of a narrative or numeric water quality criterion. If a reasonable potential exists, then water quality-based effluent limits may be established where a discharger demonstrates that 

the following conditions are met:

(i) The facility removes the intake water containing the pollutant from the same body of water into which the discharge is made;

(ii) The ambient background concentration of the pollutant does 

not meet the most stringent applicable water quality criterion for 

that pollutant;

(iii) The facility does not alter the identified intake pollutant 

chemically or physically in a manner that would cause adverse water 

quality impacts to occur that would not occur if the pollutants had 

not been removed from the body of water;

(iv) The timing and location of the discharge would not cause adverse water quality impacts to occur that would not occur if the identified intake pollutant had not been removed from the body of water;

(v) For the purpose of determining reasonable potential, the facility does not contribute any additional mass of the identified intake pollutant to its wastewater; and

(vi) For the purpose of determining water quality-based effluent 

limits; the facility does not increase the identified intake pollutant 

concentration at the point of discharge as compared to the pollutant 

concentration in the intake water. A discharger may add mass of the 

pollutant to its waste stream if an equal or greater mass is removed 

[ 17 ] OTS-6831.2
prior to discharge, so there is no net addition of the pollutant in 

the discharge compared to the intake water.

(b) Upon a finding under (a) of this subsection that an intake 

pollutant in the discharge does not cause, has the reasonable potential to cause, or contribute to an exceedance of an applicable water 

quality standard, the department is not required to include a water 

quality-based effluent limit for the identified intake pollutant in 

the facility's permit.

(c) Where intake water for a facility is provided by a municipal 

water supply system and the supplier provides treatment of the raw water that removes an intake water pollutant, the concentration of the 

intake water pollutant will be determined at the point where the water 

enters the water supplier's distribution system.

(d) Where a facility discharges intake pollutants from multiple 

sources that originate from the receiving water body and from other 

water bodies, the department may derive an effluent limit reflecting 

the flow-weighted amount of each source of the pollutant provided that 

conditions in (a) through (c) of this subsection are met and adequate 

monitoring to determine compliance can be established and is included 

in the permit.

AMENDATORY SECTION (Amending WSR 03-14-129, filed 7/1/03, effective 

8/1/03)

WAC 173-201A-510 Means of implementation. (1) Permitting. The 

primary means to be used for controlling municipal, commercial, and 

industrial waste discharges shall be through the issuance of waste 

discharge permits, as provided for in RCW 90.48.160, 90.48.162, and 

90.48.260. Waste discharge permits, whether issued pursuant to the National Pollutant Discharge Elimination System or otherwise, must be 

conditioned so the discharges authorized will meet the water quality 

standards. No waste discharge permit can be issued that causes or contributes to a violation of water quality criteria, except as provided 

for in this chapter.

(a) Persons discharging wastes in compliance with the terms and 

conditions of permits are not subject to civil and criminal penalties 

on the basis that the discharge violates water quality standards.

(b) Permits must be modified by the department when it is determined that the discharge causes or contributes to a violation of water 

quality standards. Major modification of permits is subject to review 

in the same manner as the originally issued permits.

(2) Miscellaneous waste discharge or water quality effect sources. The director shall, through the issuance of regulatory permits, 

directives, and orders, as are appropriate, control miscellaneous 

waste discharges and water quality effect sources not covered by subsection (1) of this section.

(3) Nonpoint source and storm water pollution.

(a) Activities which generate nonpoint source pollution shall be 

conducted so as to comply with the water quality standards. The primary means to be used for requiring compliance with the standards 

shall be through best management practices required in waste discharge 

permits, rules, orders, and directives issued by the department for 

activities which generate nonpoint source pollution.

[ 18 ] OTS-6831.2
(b) Best management practices shall be applied so that when all 

appropriate combinations of individual best management practices are 

utilized, violation of water quality criteria shall be prevented. If a 

discharger is applying all best management practices appropriate or 

required by the department and a violation of water quality criteria 

occurs, the discharger shall modify existing practices or apply further water pollution control measures, selected or approved by the department, to achieve compliance with water quality criteria. Best management practices established in permits, orders, rules, or directives 

of the department shall be reviewed and modified, as appropriate, so 

as to achieve compliance with water quality criteria.

(c) Activities which contribute to nonpoint source pollution 

shall be conducted utilizing best management practices to prevent violation of water quality criteria. When applicable best management 

practices are not being implemented, the department may conclude individual activities are causing pollution in violation of RCW 90.48.080. 

In these situations, the department may pursue orders, directives, 

permits, or civil or criminal sanctions to gain compliance with the 

standards.

(d) Activities which cause pollution of storm water shall be conducted so as to comply with the water quality standards. The primary 

means to be used for requiring compliance with the standards shall be 

through best management practices required in waste discharge permits, 

rules, orders, and directives issued by the department for activities 

which generate storm water pollution. The consideration and control 

procedures in (b) and (c) of this subsection apply to the control of 

pollutants in storm water.

(4) General allowance for compliance schedules.

(a) Permits((,)) and orders((, and directives of)) issued by the 

department for existing discharges may include a schedule for achieving compliance with effluent limits and water quality ((criteria contained in this chapter)) standards that apply to:

(i) Aquatic life uses; and

(ii) Uses other than aquatic life.

((Such)) (b) Schedules of compliance shall be developed to ensure 

final compliance with all water quality-based effluent limits and the 

water quality standards in the shortest practicable time. ((Decisions 

regarding)) The department will decide whether to issue schedules of 

compliance ((will be made)) on a case-by-case basis ((by the department)). Schedules of compliance may not be issued for new discharges. 

Examples of schedules of compliance that may be issued ((to allow 

for)) include:

(i) Construction of necessary treatment capability;

(ii) Implementation of necessary best management practices;

(iii) Implementation of additional storm water best management 

practices for discharges determined not to meet water quality ((criteria)) standards following implementation of an initial set of best 

management practices; and

(iv) Completion of necessary water quality studies((; or (v) resolution of a pending water quality standards' issue through rule-making action)) related to implementation of permit requirements to meet 

effluent limits.

(((b))) (c) For the period of time during which compliance with 

water quality ((criteria)) standards is deferred, interim effluent 

((limitations)) limits shall be formally established, based on the 

best professional judgment of the department. Interim effluent ((limitations)) limits may be numeric or nonnumeric (e.g., construction of 

[ 19 ] OTS-6831.2
necessary facilities by a specified date as contained in an ((ecology)) order or permit), or both.

(((c))) (d) Prior to establishing a schedule of compliance, the 

department shall require the discharger to evaluate the possibility of 

achieving water quality ((criteria)) standards via nonconstruction 

changes (e.g., facility operation, pollution prevention). Schedules of 

compliance ((may in no case exceed ten years, and)) shall meet requirements in WAC 173-220-140 and shall require compliance with the 

specified requirements as soon as practicable. Compliance schedules 

shall generally not exceed the term of any permit unless the department determines that a longer time period is needed to come into compliance with the applicable water quality standards.

(e) When an approved total maximum daily load, or TMDL, has established waste load allocations for permitted dischargers, a longer 

period of time for a compliance schedule may be authorized if the department has determined that:

(i) The permittee is not able to meet its waste load allocation 

in the TMDL solely by controlling and treating its own effluent;

(ii) The permittee has made significant progress to reduce pollutant loading during the term of the permit;

(iii) The permittee is meeting all of its requirements under the 

TMDL as soon as possible; and

(iv) Actions specified in the compliance schedule are sufficient 

to achieve water quality standards as soon as possible.

(5) Compliance schedules for dams:

(a) All dams in the state of Washington must comply with the provisions of this chapter.

(b) For dams that cause or contribute to a violation of the water 

quality standards, the dam owner must develop a water quality attainment plan that provides a detailed strategy for achieving compliance. 

The plan must include:

(i) A compliance schedule that does not exceed ten years;

(ii) Identification of all reasonable and feasible improvements 

that could be used to meet standards, or if meeting the standards is 

not attainable, then to achieve the highest attainable level of improvement;

(iii) Any department-approved gas abatement plan as described in 

WAC 173-201A-200 (1)(f)(ii);

(iv) Analytical methods that will be used to evaluate all reasonable and feasible improvements;

(v) Water quality monitoring, which will be used by the department to track the progress in achieving compliance with the state water quality standards; and

(vi) Benchmarks and reporting sufficient for the department to 

track the applicant's progress toward implementing the plan within the 

designated time period.

(c) The plan must ensure compliance with all applicable water 

quality criteria, as well as any other requirements established by the 

department (such as through a total maximum daily load, or TMDL, analysis).

(d) If the department is acting on an application for a water 

quality certification, the approved water quality attainment plan may 

be used by the department in its determination that there is reasonable assurance that the dam will not cause or contribute to a violation 

of the water quality standards.

[ 20 ] OTS-6831.2
(e) When evaluating compliance with the plan, the department will 

allow the use of models and engineering estimates to approximate design success in meeting the standards.

(f) If reasonable progress toward implementing the plan is not 

occurring in accordance with the designated time frame, the department 

may declare the project in violation of the water quality standards 

and any associated water quality certification.

(g) If an applicable water quality standard is not met by the end 

of the time provided in the attainment plan, or after completion of 

all reasonable and feasible improvements, the owner must take the following steps:

(i) Evaluate any new reasonable and feasible technologies that 

have been developed (such as new operational or structural modifications) to achieve compliance with the standards, and develop a new 

compliance schedule to evaluate and incorporate the new technology;

(ii) After this evaluation, if no new reasonable and feasible improvements have been identified, then propose an alternative to achieve compliance with the standards, such as site specific criteria 

(WAC 173-201A-430), a use attainability analysis (WAC 173-201A-440), 

or a water quality offset (WAC 173-201A-450).

(h) New dams, and any modifications to existing facilities that 

do not comply with a gas abatement or other pollution control plan established to meet criteria for the water body, must comply with the 

water quality standards at the time of project completion.

(i) Structural changes made as a part of a department approved 

gas abatement plan to aid fish passage, described in WAC 173-201A-200 

(1)(f)(ii), may result in system performance limitations in meeting 

water quality criteria for that parameter at other times of the year.

[ 21 ] OTS-6831.2