Clean Water Act discharge permit · NPDES MDG491091

MECHANICSVILLE RMC, Mechanicsville, MD: NPDES MDG491091 discharge permit, effluent exceedances, inspections, penalties

Administratively continuedPermit status
MinorDischarger class
4Pollutants under a numeric limit
2Pollutants with an effluent exceedance

MECHANICSVILLE RMC, held by HOWLIN INDUSTRIAL PARK, holds NPDES permit MDG491091, which discharges to Lockes Swamp Creek Via Lower Patuxent River. EPA’s file records it issued November 30, 2010 and expiring April 30, 2015. 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	MECHANICSVILLE RMC
Permittee as filed	HOWLIN INDUSTRIAL PARK
NPDES ID	MDG491091
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	November 30, 2010
Expiration date	April 30, 2015
Issuing agency	Maryland Department of The Environment
Address	Mechanicsville, MD 20659
Receiving water	Lockes Swamp Creek via Lower Patuxent River
Subwatershed	Indian Creek-Patuxent River (HUC 020600060601)

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

Effluent limits and exceedances

5Pollutants on file
4Under a numeric limit
5With a violation of any kind
2With 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.

Pollutant or measure	Limits	Violations, any kind	Effluent exceedances	Latest exceedance	Largest exceedance, as filed
pH	24	98	18	December 31, 2023
Solids, total suspended	24	90	12	December 31, 2023	1,920% over the limit
Flow, in conduit or thru treatment plant	24	91	0
pH change [range]	12	78	0
Oil and grease	0	29	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 MDG491091.

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 MDG491091 there.

Nearby on the register

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

This public-records page covers Clean Water Act discharge permit NPDES MDG491091 for MECHANICSVILLE RMC in Mechanicsville, MD, held by HOWLIN INDUSTRIAL PARK, which discharges to Lockes Swamp Creek via the Lower Patuxent River. The permit is listed as administratively continued, a Minor Discharger class, with 2 pollutants under a numeric limit and 2 pollutants with an effluent exceedance, and it was issued November 30, 2010 with an expiration date of April 30, 2015.