NPDES GU0020273 · Clean Water Act
UMATAC-MERIZO STP, Merizo, GU: NPDES GU0020273 discharge permit, effluent exceedances, inspections, penalties
UMATAC-MERIZO STP, Merizo, Guam: Individual permit GU0020273, held by GUAM WATERWORKS AUTHORITY; Publicly owned treatment works; Effective; issued August 19, 2015, term to August 31, 2020; discharges to TOGUAN RIVER.
- Phosphate, ortho [as PO4]: 1 limit, 277 violations of any kind, 273 effluent exceedances, latest December 31, 2025, largest 2,200% over the limit.
- Solids, suspended percent removal: 2 limits, 147 violations of any kind, 147 effluent exceedances, latest May 31, 2026, largest 20,913% over the limit.
- E. coli, colony forming units [CFU]: 0 limits, 120 violations of any kind, 118 effluent exceedances, latest August 31, 2015, largest 99,999% over the limit.
- Coliform, fecal, colony forming units: 0 limits, 114 violations of any kind, 105 effluent exceedances, latest August 31, 2015, largest 166,400% over the limit.
- BOD, 5-day, percent removal: 2 limits, 107 violations of any kind, 97 effluent exceedances, latest April 30, 2026, largest 427% over the limit.
- Enterococci: 4 limits, 92 violations of any kind, 88 effluent exceedances, latest October 31, 2022, largest 103,594% over the limit.
- Nitrogen, ammonia total [as N]: 2 limits, 83 violations of any kind, 79 effluent exceedances, latest December 31, 2025, largest 6,851% over the limit.
- Nitrogen, nitrate total [as N]: 0 limits, 83 violations of any kind, 79 effluent exceedances, latest February 28, 2015, largest 3,071% over the limit.
- Solids, total suspended: 16 limits, 79 violations of any kind, 74 effluent exceedances, latest December 31, 2025, largest 1,376% over the limit.
- Flow, in conduit or thru treatment plant: 4 limits, 74 violations of any kind, 74 effluent exceedances, latest April 30, 2026, largest 208% over the limit.
- Flow, minimum flow range: 0 limits, 51 violations of any kind, 43 effluent exceedances, latest June 30, 2026, largest 80% over the limit.
- pH: 4 limits, 21 violations of any kind, 21 effluent exceedances, latest August 31, 2019.
- Nitrite + Nitrate total [as N]: 1 limit, 6 violations of any kind, 6 effluent exceedances, latest December 31, 2019, largest 380% over the limit.
- BOD, 5-day, 20 deg. C: 16 limits, 34 violations of any kind, 2 effluent exceedances, latest September 30, 2016, largest 21% over the limit.
- Oil and grease: 0 limits, 20 violations of any kind.
- TU Static Renewal 7-Day Chronic Ceriodaphnia dubia: 0 limits, 6 violations of any kind.
- Hardness, total [as CaCO3]: 0 limits, 5 violations of any kind.
- Oil & grease, total recoverable: 2 limits, 4 violations of any kind.
- Cyanide, total [as CN]: 0 limits, 2 violations of any kind.
- Arsenic, total recoverable: 0 limits, 2 violations of any kind.
- Selenium, total recoverable: 0 limits, 2 violations of any kind.
- Thallium, total recoverable: 0 limits, 2 violations of any kind.
- Beryllium, total recoverable [as Be]: 0 limits, 2 violations of any kind.
- Arsenic, dissolved [as As]: 0 limits, 2 violations of any kind.
- Cadmium, dissolved [as Cd]: 0 limits, 2 violations of any kind.
- Copper, dissolved [as Cu]: 0 limits, 2 violations of any kind.
- Lead, dissolved [as Pb]: 0 limits, 2 violations of any kind.
- Nickel, dissolved [as Ni]: 0 limits, 2 violations of any kind.
- Nickel, total recoverable: 0 limits, 2 violations of any kind.
- Silver, total [as Ag]: 0 limits, 2 violations of any kind.
- Silver total recoverable: 0 limits, 2 violations of any kind.
- Zinc, dissolved [as Zn]: 0 limits, 2 violations of any kind.
- Zinc, total recoverable: 0 limits, 2 violations of any kind.
- Cadmium, total recoverable: 0 limits, 2 violations of any kind.
- Lead, total recoverable: 0 limits, 2 violations of any kind.
- Chromium, total recoverable: 0 limits, 2 violations of any kind.
- Copper, total recoverable: 0 limits, 2 violations of any kind.
- Chromium, hexavalent dissolved [as Cr]: 0 limits, 2 violations of any kind.
- Antimony, total recoverable: 0 limits, 2 violations of any kind.
- 2-Methyl-4,6-dinitrophenol: 0 limits, 2 violations of any kind.
- Dichlorobromomethane: 0 limits, 2 violations of any kind.
- Carbon tetrachloride: 0 limits, 2 violations of any kind.
- 1,2-Dichloroethane: 0 limits, 2 violations of any kind.
- Bromoform: 0 limits, 2 violations of any kind.
- Dibromochloromethane: 0 limits, 2 violations of any kind.
- Chloroform: 0 limits, 2 violations of any kind.
- Toluene: 0 limits, 2 violations of any kind.
- Benzene: 0 limits, 2 violations of any kind.
- .delta.-BHC: 0 limits, 2 violations of any kind.
- Acenaphthylene: 0 limits, 2 violations of any kind.
- Acenaphthene: 0 limits, 2 violations of any kind.
- Acrolein: 0 limits, 2 violations of any kind.
- Acrylonitrile: 0 limits, 2 violations of any kind.
- Anthracene: 0 limits, 2 violations of any kind.
- Benzo[b]fluoranthene: 0 limits, 2 violations of any kind.
- Benzo[k]fluoranthene: 0 limits, 2 violations of any kind.
- Benzo[a]pyrene: 0 limits, 2 violations of any kind.
- Bis[2-chloroethyl] ether: 0 limits, 2 violations of any kind.
- Bis[2-chloroethoxy]methane: 0 limits, 2 violations of any kind.
- Bis[2-chloroisopropyl] ether: 0 limits, 2 violations of any kind.
Guam holds 6 Publicly owned treatment works coverages of this permit type in EPA’s file; 3 were issued before GU0020273. GUAM WATERWORKS AUTHORITY holds 8 permits in Guam.
Other permits held by GUAM WATERWORKS AUTHORITY
- AGANA SEWERAGE TREATMENT PLANT, Hagatna: GU0020087, issued 2013-04-10
- BAZA GARDENS WWTF, Yona: GU0020095, issued 2008-11-24
- NORTHERN DISTRICT STP, Dededo: GU0020141, issued 2013-04-10
- AGAT STP, Agat: GU0020222, issued 2017-11-28
- UNKNOWN, Agat: GU0020265
- UGUM SURFACE WATER TREATMENT PLANT, Talofofo: GU0020371, issued 2016-07-08
- GUAM WATERWORKS AUTHORITY, Hagatna: GUL020222, issued 2021-01-01
Coverages issued nearest GU0020273
- 2008-11-24: BAZA GARDENS WWTF, Yona: GU0020095, held by GUAM WATERWORKS AUTHORITY
- 2013-04-10: AGANA SEWERAGE TREATMENT PLANT, Hagatna: GU0020087, held by GUAM WATERWORKS AUTHORITY
- 2013-04-10: NORTHERN DISTRICT STP, Dededo: GU0020141, held by GUAM WATERWORKS AUTHORITY
- 2016-07-08: UGUM SURFACE WATER TREATMENT PLANT, Talofofo: GU0020371, held by GUAM WATERWORKS AUTHORITY
- 2017-11-28: AGAT STP, Agat: GU0020222, held by GUAM WATERWORKS AUTHORITY
UMATAC-MERIZO STP among its neighbors
1 discharge permits are in the La Sa Fua River-Frontal Phillipine Sea subwatershed (HUC 220100000301); GU0020273 is one. Its county: 82, 4 major; GU0020273 is minor permit.
Identity
| Facility | UMATAC-MERIZO STP |
|---|---|
| Permittee | GUAM WATERWORKS AUTHORITY |
| NPDES ID | GU0020273 |
| Status | Effective |
| Type | Individual permit |
| Class | Minor |
| Facility type | Publicly owned treatment works |
| Program | Publicly owned treatment works |
| Issued | August 19, 2015 |
| Expires | August 31, 2020 |
| Address | Merizo, GU 96915 |
| Receiving water | TOGUAN RIVER |
| Subwatershed | La Sa Fua River-Frontal Phillipine Sea (HUC 220100000301) |
| Program components on file | POTW, Pretreatment |
| SIC | 4952 – Sewerage Systems |
NPDES GU0020273: effluent limits and exceedances
UMATAC-MERIZO STP (NPDES GU0020273): 155 pollutants on file, 14 limited; 152 with a violation of any kind, 14 with an exceedance.
The 60 with the most exceedances of the 155 on file for NPDES GU0020273. How exceedances are counted.
| Pollutant | Limits | Violations | Exceedances | Latest | Largest, as filed |
|---|---|---|---|---|---|
| Phosphate, ortho [as PO4] | 1 | 277 | 273 | December 31, 2025 | 2,200% over the limit |
| Solids, suspended percent removal | 2 | 147 | 147 | May 31, 2026 | 20,913% over the limit |
| E. coli, colony forming units [CFU] | 0 | 120 | 118 | August 31, 2015 | 99,999% over the limit |
| Coliform, fecal, colony forming units | 0 | 114 | 105 | August 31, 2015 | 166,400% over the limit |
| BOD, 5-day, percent removal | 2 | 107 | 97 | April 30, 2026 | 427% over the limit |
| Enterococci | 4 | 92 | 88 | October 31, 2022 | 103,594% over the limit |
| Nitrogen, ammonia total [as N] | 2 | 83 | 79 | December 31, 2025 | 6,851% over the limit |
| Nitrogen, nitrate total [as N] | 0 | 83 | 79 | February 28, 2015 | 3,071% over the limit |
| Solids, total suspended | 16 | 79 | 74 | December 31, 2025 | 1,376% over the limit |
| Flow, in conduit or thru treatment plant | 4 | 74 | 74 | April 30, 2026 | 208% over the limit |
| Flow, minimum flow range | 0 | 51 | 43 | June 30, 2026 | 80% over the limit |
| pH | 4 | 21 | 21 | August 31, 2019 | |
| Nitrite + Nitrate total [as N] | 1 | 6 | 6 | December 31, 2019 | 380% over the limit |
| BOD, 5-day, 20 deg. C | 16 | 34 | 2 | September 30, 2016 | 21% over the limit |
| Oil and grease | 0 | 20 | 0 | ||
| TU Static Renewal 7-Day Chronic Ceriodaphnia dubia | 0 | 6 | 0 | ||
| Hardness, total [as CaCO3] | 0 | 5 | 0 | ||
| Oil & grease, total recoverable | 2 | 4 | 0 | ||
| Cyanide, total [as CN] | 0 | 2 | 0 | ||
| Arsenic, total recoverable | 0 | 2 | 0 | ||
| Selenium, total recoverable | 0 | 2 | 0 | ||
| Thallium, total recoverable | 0 | 2 | 0 | ||
| Beryllium, total recoverable [as Be] | 0 | 2 | 0 | ||
| Arsenic, dissolved [as As] | 0 | 2 | 0 | ||
| Cadmium, dissolved [as Cd] | 0 | 2 | 0 | ||
| Copper, dissolved [as Cu] | 0 | 2 | 0 | ||
| Lead, dissolved [as Pb] | 0 | 2 | 0 | ||
| Nickel, dissolved [as Ni] | 0 | 2 | 0 | ||
| Nickel, total recoverable | 0 | 2 | 0 | ||
| Silver, total [as Ag] | 0 | 2 | 0 | ||
| Silver total recoverable | 0 | 2 | 0 | ||
| Zinc, dissolved [as Zn] | 0 | 2 | 0 | ||
| Zinc, total recoverable | 0 | 2 | 0 | ||
| Cadmium, total recoverable | 0 | 2 | 0 | ||
| Lead, total recoverable | 0 | 2 | 0 | ||
| Chromium, total recoverable | 0 | 2 | 0 | ||
| Copper, total recoverable | 0 | 2 | 0 | ||
| Chromium, hexavalent dissolved [as Cr] | 0 | 2 | 0 | ||
| Antimony, total recoverable | 0 | 2 | 0 | ||
| 2-Methyl-4,6-dinitrophenol | 0 | 2 | 0 | ||
| Dichlorobromomethane | 0 | 2 | 0 | ||
| Carbon tetrachloride | 0 | 2 | 0 | ||
| 1,2-Dichloroethane | 0 | 2 | 0 | ||
| Bromoform | 0 | 2 | 0 | ||
| Dibromochloromethane | 0 | 2 | 0 | ||
| Chloroform | 0 | 2 | 0 | ||
| Toluene | 0 | 2 | 0 | ||
| Benzene | 0 | 2 | 0 | ||
| .delta.-BHC | 0 | 2 | 0 | ||
| Acenaphthylene | 0 | 2 | 0 | ||
| Acenaphthene | 0 | 2 | 0 | ||
| Acrolein | 0 | 2 | 0 | ||
| Acrylonitrile | 0 | 2 | 0 | ||
| Anthracene | 0 | 2 | 0 | ||
| Benzo[b]fluoranthene | 0 | 2 | 0 | ||
| Benzo[k]fluoranthene | 0 | 2 | 0 | ||
| Benzo[a]pyrene | 0 | 2 | 0 | ||
| Bis[2-chloroethyl] ether | 0 | 2 | 0 | ||
| Bis[2-chloroethoxy]methane | 0 | 2 | 0 | ||
| Bis[2-chloroisopropyl] ether | 0 | 2 | 0 |
NPDES GU0020273: inspections, violations and enforcement
NPDES GU0020273 (UMATAC-MERIZO STP): no single-event violation, inspection, formal enforcement action and informal enforcement action on file.
Watch NPDES GU0020273
NPDES GU0020273: one email when its EPA record changes — $99/month.
Permits near NPDES GU0020273
NPDES GU0020273: 155 pollutant rows, 0 dated events; ICIS-NPDES download, loaded October 14, 2026.