Wastewater and
Storm Water

Davenport Engineering’s water quality services cover the spectrum from storm water to industrial wastewater. Our Qualified Industrial Storm Water Practitioner (QISP) and specialists are skilled at all aspects of the Industrial General Permit (IGP) ranging from No Exposure Certifications (NEC) to ERA Level 2 Action Plans and Technical Reports. On the industrial wastewater side, we can prepare POTW permits, Self-Monitoring Reports (SMR), and surcharge fee statements, and help in many other ways.

Please follow the links below to discover a few ways we can help and contact us to learn more:


Spill prevention, control, and countermeasures (SPCC) are top priorities for any facility that stores, uses, transfers, or handles oil. The objective of the SPCC Plan, required by the Oil Pollution Prevention Regulation in 40 CFR 112, is to prevent a discharge of oil from non-transportation-related facilities into navigable waters or adjoining shorelines. A good SPCC Plan documents the facility’s spill management practices and addresses the facility type and size, location relative to water bodies, materials stored, physical secondary containment structures, operations, and personnel training.

A facility is required to have an SPCC Plan if the facility has a “reasonable expectation of an oil discharge” to a waterway or adjoining shoreline and an aggregate oil storage capacity that is either:

  • · greater than 1,320 gallons aboveground, or
  • · greater than 42,000 gallons underground

For the purpose of SPCC Plans, oil is defined as any type or form of oil including, but not limited to, petroleum, fuel oil, sludge, fat, vegetable oil, synthetic oil, and mineral oil.

Facilities that are subject to the SPCC rule with less than 10,000 gallons of aggregate aboveground oil storage are classified based on certain criteria as either Tier I or Tier II. Tier I facilities are eligible to prepare and certify a SPCC Plan using the EPA Tier I SPCC template. Tier II facilities can prepare and self-certify an SPCC Plan in accordance with applicable requirements.

Facilities that are subject to the SPCC rule with more than 10,000 gallons of aggregate aboveground oil storage and meeting other criteria are classified as non-qualified facilities. These facilities must prepare a full SPCC Plan in accordance with the applicable requirements and have it certified by a Professional Engineer (PE).

Davenport Engineering has extensive experience preparing or recertifying SPCC Plans for Tier I, Tier II, and non-qualified facilities. Our licensed professional engineer (PE) and knowledgeable SPCC specialists are ready to help.

NPDES Permitting

A National Pollutant Discharge Elimination System (NPDES) permit is mandated by the Clean Water Act of 1972 for certain industrial businesses that discharge storm water runoff into a storm drain system or surface waters. In California, these facilities can either obtain a site specific individual NPDES permit or apply for coverage under the State’s General Permit for Storm Water Discharges Associated with Industrial Activities, otherwise known as the Industrial General Permit (IGP).

The IGP is an NPDES permit for facilities categorized under one of the listed SIC codes. A complete listing of California industry categories subject to the IGP can be found on the California State Water Resources Control Board website.

The IGP contains many requirements including, but not limited to:

  • · Storm Water Pollution Prevention Plan (SWPPP)
  • · Notice of Intent (NOI)
  • · Payment of fee
  • · Storm water sampling and monitoring plan
  • · Compliance reporting electronically through the State Board’s “Storm Water Multiple Application and Report Tracking System” (SMARTS)

Davenport Engineering can help you apply for permit coverage under a site specific individual NPDES permit or IGP depending on your SIC code and other facility factors.


Simply put, the Storm Water Pollution Prevention Plan (SWPPP) is a written plan to prevent storm water pollution following the framework specified in the IGP or site specific NPDES permit. The contents of the SWPPP generally include:

  • · Minimum and advanced storm water Best Management Practices (BMPs)
  • · Site Map
  • · Pollutant Numeric Action Levels (NALs)
  • · Monitoring Plan

Davenport Engineering can assist facilities with developing new SWPPP or an updating an existing SWPPP.

IGP Compliance

For facilities regulated under California’s Industrial General Permit (IGP), compliance can be achieved by either obtaining full permit coverage or a No Exposure Certification (NEC). “No Exposure” means that all “industrial activities and materials” are protected by a storm-resistant shelter from all storm water, i.e., rain, snow, and/or runoff. To obtain a NEC, the discharger must submit an application certifying the site has no potential to pollute stormwater and recertify on an annual basis. These facilities have reduced requirements, including an exemption from the SWPP Plan.

Facilities operating under the full IGP requirements, on the other hand, are subject to stormwater sampling, and depending on the results, subsequent actions. Some of the actions must be performed by a Qualified Industrial Storm Water Practitioner (QISP).

For example, a facility enters the Level 1 Exceedance Response Action (ERA) requirements when a pollutant exceeds the Numeric Action Level (NAL) on the Annual Report for the first time. The facility must then have a QISP conduct a Level 1 ERA evaluation by October 1st for the prior reporting year. The QISP evaluates the facility’s Storm Water Pollution Prevention Plan (SWPPP), Best Management Practices (BMP), and Monitoring and Implementation Plan (MIP) and recommends changes to prevent future NAL exceedances and return the facility to Baseline. The QISP then prepares, certifies, and submits an ERA Level 1 Report summarizing the BMP, SWPPP, and MIP changes to the State Water Resources Control Board (SWRCB) via the SMARTS web tool before January 1st.

A Level 1 facility enters Level 2 if the changes to its SWPPP, BMPs, and MIP do not result in pollutant levels returning below their NALs for the Annual Report due July 15th. The QISP must now complete an Exceedance Response Action (ERA) Level 2 Action Plan for submittal to the SWRCB via the SMARTS web tool before January 1st. The ERA Level 2 Action Plan must include a schedule and the selected technical demonstration for each NAL exceedance. The three available technical demonstrations, which should describe the reason for the NAL exceedance, are:

  • 1. Industrial Activity BMP Demonstration
  • 2. Non-Industrial Pollutant Source Demonstration
  • 3. Natural Background Pollutant Source Demonstration

After the facility has implemented its selected option, the QISP must prepare, certify, and submit a Technical Report detailing the outcome of the technical demonstrations prior to January 1st.

You can count on Davenport Engineering’s QISP and water specialists to take a scientific approach to navigating IGP compliance, whether preparing NECs, ERA Level 1 Evaluations and Reports, or ERA Level 2 Action Plans and Technical Reports.

POTW Permitting

Industrial facilities that discharge process waste water to a publicly owned treatment works (POTW) must do so under a wastewater discharge permit. Industrial waste water permitting requirements differ between different sanitation districts and city public works departments. Perhaps nowhere are the requirements more stringent than with the Los Angeles County Sanitation District (LACSD).

The LACSD requires industrial facilities that discharge wastewater from manufacturing, processing, or agricultural sources to the sewer system leading to their wastewater treatment plant to obtain an Industrial Wastewater (IWW) Discharge Permit. Facilities discharging for the first time must submit a complete application package, which includes a variety of information about the facility and wastewater discharge. Facilities proposing major modifications must submit a permit revision package and facilities proposing minor modifications must submit an addendum package. IWW permits are valid for a period of five years and must be renewed prior to expiration.

If you are looking for a trusted POTW permitting resource, please turn to Davenport Engineering. We can support your initial feasibility assessment; permit application for initial connection, modification, or renewal; or negotiation of discharge permit conditions.

POTW Permit Compliance

Industrial facilities with a POTW wastewater discharge permit will certainly have permit conditions that require routine attention.

A large facility with LACSD IWW discharge permit, for example, is typically required to sample its wastewater on a daily basis. These daily samples are analyzed for multiple parameters such as chemical oxygen demand (COD), suspended solids (SS), and specific pollutants. Regular evaluation of these sample results and follow up on anomalies are good ways to lower discharge fees, stay in compliance, and make report preparation as efficient as possible.

Permitted industrial dischargers with the LACSD are required to submit a Self-Monitoring Report (SMR) each quarter. The SMR includes quarterly wastewater flows, sample day flows, and one full set of sampling test results for all parameters specified in the SMR section of the discharge permit. Based on LACSD’s judgement, industrial dischargers often are required to monitor additional pollutants not required by federal or local wastewater regulations.

Another LACSD reporting obligation is the annual wastewater treatment surcharge fee on industrial wastewater dischargers who discharge more than 1 million gallons (MMgal) of wastewater each year or who discharge extremely concentrated pollutants. The annual surcharge fee calculation requires a minimum number of samples throughout the year for both COD and SS. Long Form dischargers must also report their annual peak flow, typically an average of the facility’s highest valid peak flows discharged between the hours of 8 am to 10 pm. The total annual surcharge fee is computed by summing the flow, COD, SS, and peak flow fees and adding in a small sanitary flow charge.

Davenport Engineering has wastewater expertise you can draw from to manage and execute your routine POTW compliance program.