Stormwater sampling season may be over, but for many California industrial facilities, compliance work is just beginning.

If your facility exceeded one or more Numeric Action Levels (NALs) during the 2025–2026 monitoring year, you may now be required to complete an Exceedance Response Action (ERA). Whether this is your first ERA or you've completed one before, understanding what's required now can help reduce stress, avoid delays, and strengthen your facility's stormwater compliance program.

What Is an Exceedance Response Action (ERA)?

An ERA is a formal evaluation required when stormwater sampling results exceed California's Numeric Action Levels under the Industrial General Permit (IGP).

The purpose of an ERA is to identify why pollutant levels exceeded permit thresholds, evaluate the effectiveness of your current best management practices (BMPs), and establish improvements that reduce future stormwater pollution.

What Triggers an ERA?

An ERA is triggered when one or more stormwater analytical results exceed applicable Numeric Action Levels.

Depending on your compliance history and monitoring results, your facility may be assigned either a Level 1 ERA or a Level 2 ERA.

Level 1 vs. Level 2 ERA

Common Reasons Facilities Trigger ERAs

• Outdoor material storage exposed to rainfall
• Vehicle or equipment leaks
• Poor housekeeping practices
• Ineffective or aging BMPs
• Sediment tracking
• Changes in facility operations
• Insufficient employee training
• Improper waste handling

Remember:

Many ERAs are triggered by several small issues rather than one major problem. A thorough site evaluation often identifies opportunities for simple operational improvements that significantly reduce future exceedances.

What's Included in an ERA?

Although every facility is different, most ERA reports include:

• Comprehensive site inspection
• Pollutant source identification
• Evaluation of existing BMPs
• Review of analytical monitoring data
• Recommended corrective actions
• Implementation schedule
• Documentation prepared by a Qualified Industrial Stormwater Practitioner (QISP)

Why You Should Start Early

One of the biggest mistakes facilities make is waiting until the deadline approaches before beginning the ERA process.

Preparing a quality ERA often requires:

• Reviewing historical sampling results
• Conducting multiple site inspections
• Meeting with facility personnel
• Evaluating BMP performance
• Developing practical corrective actions
• Preparing documentation for SMARTS submission

Best Practices for a Successful ERA

• Begin the process as soon as ERA requirements are issued.
• Focus on identifying root causes rather than simply explaining laboratory results.
• Document inspections with photos and detailed notes.
• Recommend realistic BMP improvements that can be maintained over time.
• Maintain thorough records of corrective actions and implementation.

How Clear Water Services Can Help

Our QISP-certified professionals assist industrial facilities throughout California with every stage of the ERA process.

• Level 1 ERA Reports
• Level 2 ERA Reports
• Site Assessments
• BMP Evaluations
• Pollutant Source Investigations
• SMARTS Reporting Assistance
• Corrective Action Planning
• Industrial General Permit Compliance Support

Check out our full permit compliance offerings.

Frequently Asked Questions

Is receiving an ERA considered a violation?

No. An ERA is a required response under the Industrial General Permit when Numeric Action Levels are exceeded. However, failing to complete ERA requirements may result in additional regulatory attention.

Can my facility prepare an ERA internally?

While facility staff can assist with information gathering, ERA reports require involvement from a Qualified Industrial Stormwater Practitioner (QISP).

Can better BMPs prevent future ERAs?

Absolutely. Many facilities successfully reduce future exceedances through improved housekeeping, source control, employee training, and updated BMPs.