1.1 Illinois EPA Regulatory Framework & Permitting

1.1 Illinois EPA Regulatory Framework & Permitting

Operating a water or wastewater facility in Illinois requires navigating both state statutes and delegated federal environmental mandates. Certified operators translate environmental laws into continuous process control to safeguard public health and receiving waterways.

Regulatory Structure & Delegated Authority

Environmental protection in Illinois operates under a bifurcated governance model established by the Illinois Environmental Protection Act (415 ILCS 5):

Under delegated authority (primacy) from U.S. EPA Region 5, the IEPA administers:

1. Clean Water Act (CWA): Administers the National Pollutant Discharge Elimination System (NPDES) permit program (§ 402), pretreatment standards (§ 307), and biosolids criteria (§ 503).
2. Safe Drinking Water Act (SDWA): Enforces National Primary Drinking Water Regulations (NPDWRs) via the Public Water System Supervision (PWSS) program (§ 1413).

Administrative Code Architecture (Title 35)

Rules adopted by the IPCB and enforced by the IEPA are compiled in Title 35 of the Illinois Administrative Code:

• Subtitle C (Water Pollution, Parts 301–399): Part 302 defines Water Quality Standards (General Use, Public Water Supply, CAWS); Part 304 sets Effluent Standards; Part 309 governs NPDES and state permits; Part 380 governs Wastewater Operator Certification.
• Subtitle F (Public Water Supplies, Parts 601–699): Part 604 establishes Design, Operation, and Maintenance rules; Part 611 incorporates federal Maximum Contaminant Levels (MCLs); Part 681 governs Drinking Water Operator Certification.

NPDES Permitting & Effluent Limitations

Wastewater discharges to waters of the State require a 5-year NPDES permit (35 Ill. Adm. Code 309). Discharge limits reflect the more restrictive of two standards: the enforceable limit is always the most stringent of TBEL or WQBEL.

1. Technology-Based Effluent Limits (TBELs): Baseline secondary treatment standards (40 CFR 133 / 35 Ill. Adm. Code 304) for municipal Publicly Owned Treatment Works (POTWs):
   • CBOD5: 30-day average ≤ 25 mg/L; 7-day average ≤ 40 mg/L (or BOD5 30/45 mg/L).
   • TSS: 30-day average ≤ 30 mg/L; 7-day average ≤ 45 mg/L.
   • Removal Efficiency: Minimum 85% removal for CBOD5/BOD5 and TSS.
   • pH Range: Maintained strictly between 6.0 and 9.0 Standard Units (S.U.).
2. Water Quality-Based Effluent Limits (WQBELs): Stringent limits derived from receiving water criteria (35 Ill. Adm. Code 302) under critical low flow (7Q10: lowest 7-day streamflow expected once every 10 years). Controls toxic parameters such as ammonia-nitrogen (seasonal summer/winter limits), dissolved oxygen (effluent DO ≥ 5.0–6.0 mg/L), and total phosphorus (monthly average 1.0 mg/L for facilities ≥ 1.0 MGD).
3. Mixing Zones (35 Ill. Adm. Code 302.102): An acute Zone of Initial Dilution (ZID) must prevent short-term lethality. A chronic mixing zone must not exceed 25% of stream flow or cross-sectional area, ensuring a continuous 75% zone of fish passage, and cannot intersect drinking water intakes.

Discharge Monitoring Reports (DMRs) & NetDMR

Permit compliance is tracked via legally binding Discharge Monitoring Reports (DMRs):

• Frequencies: Continuous (flow, pH, DO, chlorine residual); 24-hour composite (CBOD5, TSS, ammonia, phosphorus); grab samples (bacteria, temperature, oil/grease); quarterly Whole Effluent Toxicity (WET) biomonitoring (Ceriodaphnia dubia, fathead minnows).
• Electronic NetDMR: Permittees must file monthly DMRs electronically via U.S. EPA/IEPA NetDMR by the 25th (or 28th) of the following month.
• Records: Operating logs, bench sheets, and DMRs must be kept on-site for at least 3 years (sludge/biosolids records for 5 years).

Non-Compliance, Bypass & Overflow Reporting

When treatment upsets, unpermitted bypasses, or sewer overflows occur, operators must execute a mandatory two-step reporting protocol:

• Sanitary Sewer Overflows (SSOs): Raw sewage discharges from separate collection systems prior to treatment are prohibited under 35 Ill. Adm. Code 306. SSOs require 24-hour oral notification and 5-day written reports; overflows entering basements or surface waters require immediate notification of local health departments.
• Combined Sewer Overflows (CSOs): Wet-weather discharges from combined sewers are restricted under Long-Term Control Plans (LTCPs) and Nine Minimum Controls (NMC). Monitored outfalls must track event duration, rainfall, and volume on monthly DMR attachments.

Public Water Supply Compliance & Public Notification

Drinking water facilities operate under 35 Ill. Adm. Code 611 to enforce Maximum Contaminant Levels (MCLs) (e.g., Nitrate at 10 mg/L as N, Arsenic at 0.010 mg/L) or mandatory Treatment Techniques (TT) (e.g., Surface Water Treatment Rule 3-log Giardia / 4-log virus removal and filter effluent turbidity ≤ 0.3 NTU in 95% of monthly samples; Lead Action Level of 0.015 mg/L).

Under the federal and state Public Notification Rule:

• Tier 1 (Acute Hazard — within 24 hours): Broadcast media, hand delivery, reverse-911, and posting. Triggers: E. coli or fecal coliform presence; nitrate/nitrite MCL exceedance; chlorine dioxide MRDL exceedance at entry point; turbidity > 1.0 NTU with IEPA Tier 1 designation; waterborne disease outbreak.
• Tier 2 (Non-Acute Health Risk — within 30 days): Direct customer mail/notice. Triggers: Chemical/radiological MCL exceedances (e.g., TTHM > 80 µg/L, HAA5 > 60 µg/L), treatment technique violations.
• Tier 3 (Operational Failures — within 1 year): Annual Consumer Confidence Report (CCR). Triggers: Monitoring and testing violations, operating under variances.

Boil Orders Under 35 Ill. Adm. Code 604.135

Illinois does not leave boil orders to utility discretion — 35 Ill. Adm. Code 604.135(c) ("Repair Work and Emergency Operation") sets the rules, and operators are tested on them.

Trigger 1 — persistent microbiological contamination. Whenever microbiological analysis shows contamination persisting in a community water supply, the owner or official custodian must notify all consumers to boil all water used for consumption or culinary purposes for five minutes. If the owner fails to act, the Agency may issue the boil order directly to consumers.

Trigger 2 — pressure loss below 20 psi. When pressure falls below 20 psi on any portion of the distribution system for any amount of time, the owner or official custodian must issue a boil order unless the Agency has issued a Significant Events Package (SEP) and all three of the following hold:

If chlorine residual drops significantly or turbidity rises during that monitoring, the boil order must be issued anyway.

Lifting the order. Under 604.135(c)(1)(B) a boil order stays in effect until appropriate corrective action approved by the Agency is taken and microbiological samples demonstrate that the water is safe for domestic use. The Illinois rule fixes no universal sample count or waiting interval — the Agency sets that case by case. Practical operator steps are: restore and hold pressure above 20 psi system-wide, flush the affected mains, re-establish the 604.725(a) residual, sample as the Agency directs, and issue a rescission notice only after Agency approval.

Related notification duty. Under 604.135(c)(2), operators must immediately notify the appropriate IEPA Regional Office when a supply is known or suspected to be contaminated or finished water quality is degraded by equipment malfunction. On weekends, holidays and after hours, notification goes through the Illinois Emergency Management Agency at 1-800-782-7860. Issuing a boil order does not substitute for public notification under 35 Ill. Adm. Code 611.Subpart V.