Clean Water Act discharge permit · NPDES COG318013

Z BLOCK, Denver, CO: NPDES COG318013 discharge permit, effluent exceedances, inspections, penalties

Administratively continuedPermit status
MinorDischarger class
143Pollutants under a numeric limit
3Pollutants with an effluent exceedance

Z BLOCK, held by BLK220 LLC, holds NPDES permit COG318013, which discharges to South Platte River. EPA’s file records it issued July 23, 2020 and expiring May 31, 2025. The status and dates are as EPA’s permit file stood when Velarion loaded it (September 15, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.

Identity

Facility as filed	Z BLOCK
Permittee as filed	BLK220 LLC
NPDES ID	COG318013
Permit status	Administratively continued (past its expiration date and still in force until reissued)
Permit type	Coverage under a general permit
Discharger class	Minor discharger
Facility type	Not a publicly owned treatment works
Issued	July 23, 2020
Expiration date	May 31, 2025
Address	Denver, CO 80202
Receiving water	South Platte River
Receiving water impaired	303(D) Listed
Subwatershed	Cherry Creek-South Platte River (HUC 101900030304)

Cited to the EPA ICIS-NPDES permit file (ECHO download).

Effluent limits and exceedances

143Pollutants on file
143Under a numeric limit
30With a violation of any kind
3With 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 143 are shown.

Pollutant or measure	Limits	Violations, any kind	Effluent exceedances	Latest exceedance	Largest exceedance, as filed
Copper, potentially dissolved	6	1	1	October 31, 2022	41% over the limit
Arsenic, total recoverable	4	1	1	November 30, 2024	45% over the limit
Chloride [as Cl]	3	1	1	August 31, 2022	88% over the limit
1,2,3,7,8,9-Hexachlorodibenzo-p-dioxin	3	8	0
PFAS Sum	4	2	0
Perfluorooctanoic acid (PFOA)	2	2	0
Perfluorobutanoic acid (PFBA)	2	2	0
Perfluorooctanesulfonamide (PFOSA)	2	2	0
Perfluoropentanoic acid (PFPeA)	2	2	0
Perfluorohexanoic acid (PFHxA)	2	2	0
Perfluoroheptanoic acid (PFHpA)	2	2	0
Perfluorononanoic acid (PFNA)	2	2	0
Perfluorodecanoic acid (PFDA)	2	2	0
Perfluoroundecanoic acid (PFUnA)	2	2	0
Perfluorododecanoic acid (PFDoA)	2	2	0
Perfluorotridecanoic acid (PFTrDA)	2	2	0
Perfluorotetradecanoic acid (PFTeDA)	2	2	0
N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)	2	2	0
N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)	2	2	0
Perfluorobutanesulfonic acid (PFBS)	2	2	0
Perfluorodecanesulfonic acid (PFDS)	2	2	0
Perfluoroheptanesulfonic acid (PFHpS)	2	2	0
Perfluorohexanesulfonic acid (PFHxS)	2	2	0
Perfluorooctanesulfonic acid (PFOS)	2	2	0
1H,1H,2H,2H-Perfluorohexane sulfonic acid (4:2 FTS)	2	2	0
1H,1H,2H,2H-Perfluorooctane sulfonic acid (6:2 FTS)	2	2	0
1H,1H, 2H, 2H-Perfluorodecane sulfonic acid (8:2 FTS)	2	2	0
Perfluoropentanesulfonic acid (PFPeS)	2	2	0
Perfluorononanesulfonic acid (PFNS)	2	2	0
Hexafluoropropylene oxide dimer acid (HFPO-DA)	2	2	0
N-Nitrosodiphenylamine	5	0	0
Manganese, dissolved [as Mn]	4	0	0
Di[2-ethylhexyl] phthalate [DEHP]	4	0	0
Chlorine, total residual	4	0	0
pH	2	0	0
Solids, total suspended	2	0	0
Iron, 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
Barium, total recoverable	2	0	0
Iron, dissolved [as Fe]	2	0	0
Nickel, total recoverable	2	0	0
Silver total recoverable	2	0	0
Zinc, total recoverable	2	0	0
Aluminum, total recoverable	2	0	0
Cadmium, total recoverable	2	0	0
Lead, total recoverable	2	0	0
Chromium, total recoverable	2	0	0
Copper, total recoverable	2	0	0
Molybdenum, total recoverable	2	0	0
Chromium, hexavalent dissolved [as Cr]	2	0	0
Antimony, total recoverable	2	0	0
Zinc, potentially dissolved	2	0	0
Silver, potentially dissolved	2	0	0
Arsenic, potentially dissolved	2	0	0
Cadmium, potentially dissolvd	2	0	0
Chromium, trivalent, potentially dissolvd	2	0	0
Lead, potentially dissolvd	2	0	0
Manganese, potentially dissolvd	2	0	0

Cited to the EPA ICIS-NPDES limits and effluent violations files (ECHO download); up to 60 rows shown, most exceedances first.

Inspections, violations and enforcement

0Single-event violations

EPA’s single-event violation file, as loaded, holds no violation for NPDES COG318013.

Velarion’s copy of EPA’s ICIS-NPDES files does not include the inspections, formal enforcement actions and informal enforcement actions files, so this page shows none of them. EPA’s free Detailed Facility Report on ECHO lists this permit’s inspections, enforcement actions and penalties.

Cited to the EPA ICIS-NPDES violation, inspection and enforcement files (ECHO download); up to 50 rows of each shown, newest first.

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EPA publishes a free Detailed Facility Report for every permit on ECHO: its compliance status quarter by quarter, its inspections, and its enforcement actions and penalties. EPA also sends free notices of new inspections and enforcement actions through ECHO Notify; enter NPDES ID COG318013 there.

Nearby on the register

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

This public-records page covers NPDES permit COG318013 for Z BLOCK in Denver, CO, held by BLK220 LLC and discharging to the South Platte River, with its permit status shown as administratively continued. The page lists 143 pollutants on file, 3 of which are under a numeric limit, 30 with a violation of any kind, and 3 with an effluent exceedance.