Clean Water Act discharge permit · NPDES NN0020281

KAYENTA WASTEWATER TREATMENT LAGOON, Kayenta, AZ: NPDES NN0020281 discharge permit, effluent exceedances, inspections, penalties

Administratively continuedPermit status
MinorDischarger class
140Pollutants under a numeric limit
11Pollutants with an effluent exceedance
0Inspections on file
0Formal enforcement actions

KAYENTA WASTEWATER TREATMENT LAGOON, held by NAVAJO TRIBAL UTILITY AUTHORITY, holds NPDES permit NN0020281, which discharges to Laguana & Chinle Wash San Juan Rvr. EPA’s file records it issued June 12, 2018 and expiring July 31, 2023.

KAYENTA WASTEWATER TREATMENT LAGOON, Kayenta, Arizona: Individual permit NN0020281, held by NAVAJO TRIBAL UTILITY AUTHORITY; Publicly owned treatment works; Administratively continued (past its expiration date and still in force until reissued); issued June 12, 2018, term to July 31, 2023; discharges to LAGUANA & CHINLE WASH SAN JUAN RVR.

BOD, 5-day, 20 deg. C: 10 limits, 164 violations of any kind, 131 effluent exceedances, latest December 31, 2025, largest 471% over the limit.
Solids, total suspended: 10 limits, 112 violations of any kind, 79 effluent exceedances, latest April 30, 2015, largest 460% over the limit.
Nitrogen, ammonia total [as N]: 6 limits, 75 violations of any kind, 59 effluent exceedances, latest December 31, 2025, largest 2,720% over the limit.
E. coli: 4 limits, 68 violations of any kind, 56 effluent exceedances, latest December 31, 2025, largest 99,999% over the limit.
pH: 4 limits, 51 violations of any kind, 39 effluent exceedances, latest September 30, 2024.
Chlorine, total residual: 2 limits, 58 violations of any kind, 30 effluent exceedances, latest September 30, 2011, largest 19,900% over the limit.
Solids, suspended percent removal: 2 limits, 35 violations of any kind, 27 effluent exceedances, latest December 31, 2025, largest 920% over the limit.
BOD, 5-day, percent removal: 2 limits, 17 violations of any kind, 9 effluent exceedances, latest December 31, 2025, largest 220% over the limit.
Chronic Mthd Sublethal Endpt, %Effect, Median TSTcHo R/nR Pass/Fail, StatR8dmax C dubia: 0 limits, 17 violations of any kind, 2 effluent exceedances, latest November 30, 2025, largest 2,147,483,650% over the limit.
Chronic Mthd Sublethal Endpt, %Effect, Median TSTcHo R/nR Pass/Fail, StatR7d P promelas: 0 limits, 17 violations of any kind, 2 effluent exceedances, latest November 30, 2025, largest 2,147,483,650% over the limit.
Chronic Mthd Growth Endpt, %Effect, Median TSTcHo R/nR Pass/Fail, Static96hr R subcapitata: 0 limits, 22 violations of any kind, 1 effluent exceedance, latest November 30, 2025, largest 2,147,483,650% over the limit.
Pass/Fail Static Renewal 7 Day Chronic Ceriodaphnia dubia: 4 limits, 66 violations of any kind, 0 effluent exceedances.
Pass/Fail Static Renewal 7Day Chronic Pimephales promelas: 4 limits, 66 violations of any kind, 0 effluent exceedances.
TU Static Renewal 7-Day Chronic Ceriodaphnia dubia: 0 limits, 46 violations of any kind, 0 effluent exceedances.
TU Static Renewal 7-Day Chronic Pimphales promelas: 0 limits, 46 violations of any kind, 0 effluent exceedances.
Flow, in conduit or thru treatment plant: 8 limits, 24 violations of any kind, 0 effluent exceedances.
Solids, total dissolved: 6 limits, 18 violations of any kind, 0 effluent exceedances.
Temperature, water deg. fahrenheit: 0 limits, 13 violations of any kind, 0 effluent exceedances.
Nitrogen, ammonia [NH3-N]: 0 limits, 3 violations of any kind, 0 effluent exceedances.
TU Static 4 Day Chronic Raphidocelis subcapitata (formerly Selenastrum capricornutum): 0 limits, 2 violations of any kind, 0 effluent exceedances.
Temperature, water deg. centigrade: 4 limits, 0 violations of any kind, 0 effluent exceedances.
Cyanide, total [as CN]: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Asbestos: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Arsenic, total recoverable: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Selenium, total recoverable: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Thallium, total recoverable: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Beryllium, total recoverable [as Be]: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Chromium, hexavalent [as Cr]: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Chromium, trivalent [as Cr]: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Nickel, total recoverable: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Silver total recoverable: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Zinc, total recoverable: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Cadmium, total recoverable: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Lead, total recoverable: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Copper, total recoverable: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Antimony, total recoverable: 2 limits, 0 violations of any kind, 0 effluent exceedances.
2-Methyl-4,6-dinitrophenol: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Dichlorobromomethane: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Carbon tetrachloride: 2 limits, 0 violations of any kind, 0 effluent exceedances.
1,2-Dichloroethane: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Bromoform: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Dibromochloromethane: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Chloroform: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Toluene: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Benzene: 2 limits, 0 violations of any kind, 0 effluent exceedances.
.delta.-BHC: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Acenaphthylene: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Acenaphthene: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Acrolein: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Acrylonitrile: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Anthracene: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Benzo[b]fluoranthene: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Benzo[k]fluoranthene: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Benzo[a]pyrene: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Bis[2-chloroethyl] ether: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Bis[2-chloroethoxy]methane: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Bis[2-chloroisopropyl] ether: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Butyl benzyl phthalate: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Chlorobenzene: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Chrysene: 2 limits, 0 violations of any kind, 0 effluent exceedances.

October 20, 2026: Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment (EP6).
December 16, 2025: Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment (EP6).
October 20, 2025: Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment (EP6).
August 10, 2025: Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment (EP6).
May 2, 2025: Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment (EP6).
January 3, 2025: Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment (EP6).
September 22, 2024: Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment (EP6).
September 1, 2024: Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment (EP6).
August 23, 2024: Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment (EP6).
August 20, 2024: Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment (EP6).
August 14, 2024: Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment (EP6).
March 11, 2024: Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment (EP6).
February 27, 2024: Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment (EP6).

Arizona holds 91 Publicly owned treatment works coverages of this permit type in EPA’s file; 43 were issued before NN0020281. NAVAJO TRIBAL UTILITY AUTHORITY holds 8 permits in Arizona.

Other permits held by NAVAJO TRIBAL UTILITY AUTHORITY

CHINLE WWTF, Chinle: NN0020265, issued July 10, 2018
TUBA CITY WWTF, Tuba City: NN0020290, issued May 23, 2016
WINDOW ROCK WWTF, Fort Defiance: NN0021555, issued January 21, 2016
GANADO WWTP, Ganado: NN0022195, issued December 8, 2015
PINON WWTF, Pinon: NN0024228, issued August 16, 2011
KAYENTA WASTEWATER TREATMENT LAGOON, Kayenta: NNL020281, issued December 6, 2024
GANADO WWTP, Ganado: NNL022195, issued January 30, 2024

Coverages issued nearest NN0020281

December 20, 2017: UPPER VILLAGE OF MOENKOPI WWTF, Tuba City, AZ0024619, held by UPPER VILLAGE OF MOENKOPI (UVM)
January 19, 2018: USDOI NPS - GRAND CANYON NP - SOUTH RIM WWTP, Grand Canyon, AZ0022152, held by Usdoi Nps - Grand Canyon Np
January 26, 2018: USDOI NPS - GRAND CANYON NP - NORTH RIM WWTP, Grand Canyon, AZ0110426, held by Grand Canyon National Park
May 8, 2018: TOWN OF SUPERIOR WWTP, Superior, AZ0021199, held by Town Of Superior Public Works
June 7, 2018: AGUA NUEVA WRF, Tucson, AZ0026107, held by Pima County - Regional Wastewater Reclamation Department
July 10, 2018: CHINLE WWTF, Chinle, NN0020265, held by NAVAJO TRIBAL UTILITY AUTHORITY
December 27, 2018: CITY OF AVONDALE - WRF, Avondale, AZ0023281, held by City Of Avondale
March 6, 2019: CITY OF GOODYEAR - RAINBOW VALLEY WRF, Goodyear, AZ0025135, held by City Of Goodyear
April 3, 2019: TOWN OF WINKELMAN - WWTP, Winkelman, AZ0020176, held by Town Of Winkelman
May 3, 2019: PIMA COUNTY - TRES RIOS WWRF, Tucson, AZ0020001, held by Pima County - Regional Wastewater Reclamation Department

KAYENTA WASTEWATER TREATMENT LAGOON among its neighbors

EPA’s permit file holds 40 discharge permits in the Town of Kayenta-Laguna Creek subwatershed (HUC 140802041307), NN0020281 among them. Its county holds 33, 2 of them major permits; NN0020281 is a minor permit.

Other permits in the Town of Kayenta-Laguna Creek subwatershed (HUC 140802041307)

AMIGO GAS EXTENSION, Kayenta: AZR10I0PU, not classed
BAKER MIDDLE SCHOOL ATHLETIC INPROVEMENTS, Kayenta: AZR10I1D8, minor permit, permit term to February 16, 2027
KAYENTA CHURCH'S CHICKEN, Kayenta: AZR10I0G7, not classed
KAYENTA LOOP, Kayenta: AZR10I0BI, not classed
KAYENTA NHA AZ-12-73 - 15 UNITS, Kayenta: AZR10I0CS, not classed
KAYENTA SEWER LAGOON GAS SERVICE LINE EXT., Kayenta: AZR10I1FP, not classed
KAYENTA SEWER LAGOON GAS SERVICE LINE EXT., Kayenta: AZR10I1FW, not classed
KAYENTA SONIC DRIVE IN, Kayenta: AZR10I0G6, not classed
KAYENTA WASTEWATER TREATMENT LAGOON, Kayenta: NNL020281, minor permit, permit term to December 31, 2025
KUSD BUSINESS CENTER GAS EXTENSION, Kayenta: AZR10I0JB, not classed

Identity

Facility as filed	KAYENTA WASTEWATER TREATMENT LAGOON
Permittee as filed	NAVAJO TRIBAL UTILITY AUTHORITY
NPDES ID	NN0020281
Permit status	Administratively continued (past its expiration date and still in force until reissued)
Permit type	Individual permit
Discharger class	Minor discharger
Facility type	Publicly owned treatment works
Program	Publicly owned treatment works
Issued	June 12, 2018
Expiration date	July 31, 2023
Address	Kayenta, AZ 86033
Receiving water	LAGUANA & CHINLE WASH SAN JUAN RVR
Subwatershed	Town of Kayenta-Laguna Creek (HUC 140802041307)

Effluent limits and exceedances

148Pollutants on file
140Under a numeric limit
20With a violation of any kind
11With an effluent exceedance

An effluent exceedance is a discharge monitoring report value over the permit’s numeric limit (EPA’s violation code E90). A violation of any kind also counts a report not filed. Each row is EPA’s own count for that pollutant; the 60 with the most exceedances of 148 are shown.

Pollutant or measure	Limits	Violations, any kind	Effluent exceedances	Latest exceedance	Largest exceedance, as filed
BOD, 5-day, 20 deg. C	10	164	131	December 31, 2025	471% over the limit
Solids, total suspended	10	112	79	April 30, 2015	460% over the limit
Nitrogen, ammonia total [as N]	6	75	59	December 31, 2025	2,720% over the limit
E. coli	4	68	56	December 31, 2025	99,999% over the limit
pH	4	51	39	September 30, 2024
Chlorine, total residual	2	58	30	September 30, 2011	19,900% over the limit
Solids, suspended percent removal	2	35	27	December 31, 2025	920% over the limit
BOD, 5-day, percent removal	2	17	9	December 31, 2025	220% over the limit
Chronic Mthd Sublethal Endpt, %Effect, Median TSTcHo R/nR Pass/Fail, StatR8dmax C dubia	0	17	2	November 30, 2025	2,147,483,650% over the limit
Chronic Mthd Sublethal Endpt, %Effect, Median TSTcHo R/nR Pass/Fail, StatR7d P promelas	0	17	2	November 30, 2025	2,147,483,650% over the limit
Chronic Mthd Growth Endpt, %Effect, Median TSTcHo R/nR Pass/Fail, Static96hr R subcapitata	0	22	1	November 30, 2025	2,147,483,650% over the limit
Pass/Fail Static Renewal 7 Day Chronic Ceriodaphnia dubia	4	66	0
Pass/Fail Static Renewal 7Day Chronic Pimephales promelas	4	66	0
TU Static Renewal 7-Day Chronic Ceriodaphnia dubia	0	46	0
TU Static Renewal 7-Day Chronic Pimphales promelas	0	46	0
Flow, in conduit or thru treatment plant	8	24	0
Solids, total dissolved	6	18	0
Temperature, water deg. fahrenheit	0	13	0
Nitrogen, ammonia [NH3-N]	0	3	0
TU Static 4 Day Chronic Raphidocelis subcapitata (formerly Selenastrum capricornutum)	0	2	0
Temperature, water deg. centigrade	4	0	0
Cyanide, total [as CN]	2	0	0
Asbestos	2	0	0
Arsenic, total recoverable	2	0	0
Selenium, total recoverable	2	0	0
Thallium, total recoverable	2	0	0
Beryllium, total recoverable [as Be]	2	0	0
Chromium, hexavalent [as Cr]	2	0	0
Chromium, trivalent [as Cr]	2	0	0
Nickel, total recoverable	2	0	0
Silver total recoverable	2	0	0
Zinc, total recoverable	2	0	0
Cadmium, total recoverable	2	0	0
Lead, total recoverable	2	0	0
Copper, total recoverable	2	0	0
Antimony, total recoverable	2	0	0
2-Methyl-4,6-dinitrophenol	2	0	0
Dichlorobromomethane	2	0	0
Carbon tetrachloride	2	0	0
1,2-Dichloroethane	2	0	0
Bromoform	2	0	0
Dibromochloromethane	2	0	0
Chloroform	2	0	0
Toluene	2	0	0
Benzene	2	0	0
.delta.-BHC	2	0	0
Acenaphthylene	2	0	0
Acenaphthene	2	0	0
Acrolein	2	0	0
Acrylonitrile	2	0	0
Anthracene	2	0	0
Benzo[b]fluoranthene	2	0	0
Benzo[k]fluoranthene	2	0	0
Benzo[a]pyrene	2	0	0
Bis[2-chloroethyl] ether	2	0	0
Bis[2-chloroethoxy]methane	2	0	0
Bis[2-chloroisopropyl] ether	2	0	0
Butyl benzyl phthalate	2	0	0
Chlorobenzene	2	0	0
Chrysene	2	0	0

Inspections, violations and enforcement

13Single-event violations

Date	What EPA recorded	Agency
October 20, 2026	Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment	EP6
December 16, 2025	Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment	EP6
October 20, 2025	Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment	EP6
August 10, 2025	Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment	EP6
May 2, 2025	Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment	EP6
January 3, 2025	Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment	EP6
September 22, 2024	Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment	EP6
September 1, 2024	Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment	EP6
August 23, 2024	Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment	EP6
August 20, 2024	Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment	EP6
August 14, 2024	Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment	EP6
March 11, 2024	Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment	EP6
February 27, 2024	Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment	EP6

Inspections

EPA’s inspection file holds no inspection for NPDES NN0020281.

Formal enforcement and penalties

0 formal actions, 0 of them with a penalty assessed. Federal and state penalties are separate figures from separate authorities and are shown as each was filed, never added together.

Informal enforcement

EPA’s informal enforcement file holds no action for NPDES NN0020281.

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Figures from EPA’s ICIS-NPDES download, loaded September 15, 2026.

This public-records page covers the Clean Water Act discharge permit NPDES NN0020281 for the Kayenta Wastewater Treatment Lagoon in Kayenta, AZ, held by Navajo Tribal Utility Authority, with a permit status of administratively continued and a discharger class of Minor. The page lists 11 pollutants under a numeric limit and 140 pollutants with an effluent exceedance, though the facts give these counts in a form that should be read against the source record.