Clean Water Act discharge permit · NPDES ILR10ZGQE

SILVERTHORNE TOWNHOMES PHASE I, II AND III, Cortland, IL: NPDES ILR10ZGQE discharge permit, effluent exceedances, inspections, penalties

EffectivePermit status
MinorDischarger class
0Pollutants under a numeric limit
0Pollutants with an effluent exceedance
0Inspections on file
0Formal enforcement actions

SILVERTHORNE TOWNHOMES PHASE I, II AND III, held by Silverthorne Group, holds NPDES permit ILR10ZGQE. EPA’s file records it issued March 29, 2026 and expiring August 31, 2028.

SILVERTHORNE TOWNHOMES PHASE I, II AND III, Cortland, Illinois: Coverage under a general permit ILR10ZGQE, held by Silverthorne Group; Construction stormwater; Effective; issued March 29, 2026, term to August 31, 2028, by IEPA.

Illinois holds 5,215 Construction stormwater coverages of this permit type in EPA’s file; 4,367 were issued before ILR10ZGQE.

Coverages issued nearest ILR10ZGQE

March 28, 2026: SCOVILL SENIOR ACTIVITY CENTER, Decatur, ILR10ZGQ5, held by Decatur Park District
March 28, 2026: BEMES ROAD SOLAR, Crete, ILR10ZGQ6, held by Knobelsdorff Energy, LLC
March 28, 2026: EAMES STREET (US RTE 6) WATER MAIN EXTENSION, Channahon, ILR10ZGQ8, held by Steve Spiess Construction, Inc.
March 29, 2026: CHESTNUT SUBDIVISION, Arlington Heights, ILR10ZGQ9, held by Clim Development LLC
March 29, 2026: COLLEGE OF LAKE COUNTY - ROADWAY AND OUTDOOR SPORTS COMPLEX, Grayslake, ILR10ZGQA, held by Pepper Construction
March 29, 2026: VALERIAN SOLAR, LLC, Elwood, ILR10ZGQF, held by Knobelsdorff Energy, LLC
March 29, 2026: KICKAPOO-EDWARDS ROAD & CIVIL DEFENSE ROAD, Edwards, ILR10ZGQH, held by William Charles Construction Company, LLC
March 29, 2026: RECONSTRUCT TAXIWAY D, Waukegan, ILR10ZGQI, held by Alliance Contractos, Inc
March 29, 2026: THE RESIDENCES AT RIVER POINTE, Batavia, ILR10ZGQJ, held by TBD
March 30, 2026: SV CSG MADDEN CREEK SOLAR, LLC, Blue Ridge Township, ILR10ZGO6, held by Rethink Electric

SILVERTHORNE TOWNHOMES PHASE I, II AND III among its neighbors

EPA’s permit file holds 29 discharge permits in the East Branch Kishwaukee River subwatershed (HUC 070900060504), ILR10ZGQE among them.

Other permits in the East Branch Kishwaukee River subwatershed (HUC 070900060504)

ADDISON - NORTH STP, Addison: IL0033812, major permit, discharging to SALT CREEK, permit term to December 31, 2020
B - O USED AUTO PARTS, Sycamore: ILR001710, minor permit, permit term to April 30, 2014
COLE PALLET SITE IMPROVEMENTS, Sycamore: ILR10ZEMG, minor permit, permit term to August 31, 2028
DEKALB COUNTY HISTORY CENTER, Sycamore: ILR10ZF9H, minor permit, permit term to August 31, 2028
DEKALB TAYLOR MUNICIPAL AIRPOR, Dekalb: ILR002954, minor permit, permit term to June 1, 2008
FINAL PLAT NO. 1 OF SYCAMORE CROSSINGS - CONSTRUCTION OF RESIDENTIAL BUILDINGS, Sycamore: ILR10ZAS8, minor permit, permit term to August 31, 2028
FIRE STATION NO. 1, Sycamore: ILR10ZF9A, minor permit, permit term to August 31, 2028
FLOIT SND & GRVL-SYCAMORE PLNT, Sycamore: ILR003635, minor permit, permit term to June 1, 2008
GEM, De Kalb: ILR002889, minor permit, permit term to June 1, 2008
GREAT WESTERN TRAIL EXTENSION SEGMENT 2, Sycamore: ILR10ZFXZ, minor permit, permit term to August 31, 2028

What the register holds for SILVERTHORNE TOWNHOMES PHASE I, II AND III: its NPDES ID, its permit type and status, its dates, its address in Cortland, Illinois. EPA’s effluent violation file and its single-event violation file hold no violation for NPDES ILR10ZGQE.

Identity

Facility as filed	SILVERTHORNE TOWNHOMES PHASE I, II AND III
Permittee as filed	Silverthorne Group
NPDES ID	ILR10ZGQE
Permit status	Effective
Permit type	Coverage under a general permit
Discharger class	Minor discharger
Facility type	Not a publicly owned treatment works
Program	Construction stormwater
Issued	March 29, 2026
Expiration date	August 31, 2028
Issuing agency	IEPA
Address	Cortland, IL 60112
Subwatershed	East Branch Kishwaukee River (HUC 070900060504)

Effluent limits and exceedances

0Pollutants on file
0Under a numeric limit
0With a violation of any kind
0With an effluent exceedance

EPA’s limits and effluent violation files hold no pollutant row for NPDES ILR10ZGQE.

Inspections, violations and enforcement

0Single-event violations

EPA’s single-event violation file, as loaded, holds no violation for NPDES ILR10ZGQE.

Inspections

EPA’s inspection file holds no inspection for NPDES ILR10ZGQE.

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 ILR10ZGQE.

Watch this permit

One permit holder, $99/month. Watch the register for one permit holder and the places and receiving waters tied to its permits. Choose “One permit holder” and enter this permit’s NPDES ID, ILR10ZGQE.

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Nearby on the register

Figures from EPA’s ICIS-NPDES download, loaded October 14, 2026.

Cortland has 3 storm water construction permits on EPA's NPDES register, and SILVERTHORNE TOWNHOMES PHASE I, II AND III is among them. The East Branch Kishwaukee River subwatershed (HUC 070900060504) includes 29 NPDES permits, counting this permit. Permit ILR10ZGQE was issued March 29, 2026 and expires August 31, 2028.