CHAPTER 3: SOURCE CONTROL INVENTORY
DEVELOPMENT, UPDATES, AND
PRIORITIZATION
PART OF THE SOURCE CONTROL (BUSINESS/SITE)
INSPECTION PROGRAM GUIDANCE MANUAL
Prepared for
2606 West Pioneer
Puyallup, Washington 98371
Funding Provided by
Stormwater Action Monitoring (SAM)
Prepared by
Herrera Environmental Consultants, Inc.
2200 Sixth Avenue, Suite 1100
Seattle, Washington 98121
Telephone: 206-441-9080
April 29, 2022
Note:
Some pages in this document have been purposely skipped or blank pages inserted
so that this document will print correctly when duplexed.
Table of Contents
cc_20-07522-000_scmanual_ch3_inventorydev_20220429.docx
CONTENTS
Source Control Inventory Development, Updates, and Prioritization ………………………………………… 1
3.1. Permit Requirements ………………………………………………………………………………………………………………….. 1
3.2. Recommended Process ……………………………………………………………………………………………………………… 4
3.3. Prioritization ……………………………………………………………………………………………………………………………….. 11
TABLES
Table 3.1. Potential Sources of Pollutants and Crosswalk of SIC/NAICS Codes (from
Appendix 8 of the NPDES Municipal Stormwater permits). ………………………………………………. 2
Table 3.2. Data Sources for Source Control Inventory Development and Updates. ……………………….. 7
FIGURES
Figure 3.1. Recommended Steps for Developing and Updating a Source Control
Inventory. …………………………………………………………………………………………………………………………………… 6
Chapter 3: Source Control Inventory Development, Updates, and Prioritization
April 2022
Source Control (Business/Site) Inspection Program Guidance Manual
3. SOURCE CONTROL INVENTORY
DEVELOPMENT, UPDATES, AND
PRIORITIZATION
This chapter summarizes the permit requirements related to developing a source control
inventory, provides a recommended process for developing and updating a source control
inventory, and also provides information on prioritizing businesses/sites for inspection.
3.1. PERMIT REQUIREMENTS
Chapter 1: Background and Regulatory Requirements of this manual provided a high-level
overview of the National Pollutant Discharge Elimination System (NPDES) Municipal Stormwater
permit requirements related to the source control inventory. This chapter provides additional
detail and clarification regarding the NPDES Municipal Stormwater permit requirements and
how they impact the development and maintenance of a source control inventory, with a focus
on the Western Washington Phase II Permit requirements. The following are minimum
requirements to include in the source control inventory (Western Washington 2019-2024
Phase II Permit, S5.C.8.b.ii.):
Permittees shall establish an inventory that identifies publicly and privately
owned institutional, commercial, and industrial sites which have the potential to
generate pollutants to the [municipal separate storm sewer system] MS4. The
inventory shall include:
(a)
Businesses and/or sites identified based on the presence of activities that
are pollutant generating (refer to Appendix 8).
(b)
Other pollutant generating sources, based on complaint response, such as:
home-based businesses and multi-family sites.
Table 3.1 summarizes the North American Industry Classification System (NAICS) and
corresponding Standard Industrial Classification (SIC) codes that are included in Appendix 8 of
the 2019-2024 NPDES Municipal Stormwater permits. This list of businesses is intended to be
used as a starting point for the development of a source control inventory.
Chapter 3: Source Control Inventory Development, Updates, and Prioritization
April 2022
Source Control (Business/Site) Inspection Program Guidance Manual
Table 3.1. Potential Sources of Pollutants and Crosswalk of SIC/NAICS
Codes (from Appendix 8 of the NPDES Municipal Stormwater permits).
Group Description
SIC
Major
Group
SIC Industry
Group No.
NAICS Major Group
Support Activities for Animal Production
074, 075
1152xx,
Construction of Buildings
236
Heavy and Civil Engineering Construction
237
Specialty Trade Contractors
238
Beverage, Food, and Tobacco Manufacturing
311, 312
Wood Product Manufacturing
321
Paper Manufacturing
3221xx, 3222xx
Printing and Related Support Activities
323
Chemical Manufacturing
325
Petroleum and Coal Products Manufacturing
3241xx
Plastics and Rubber Product Manufacturing
326
Leather and Allied Product Manufacturing
316
Nonmetallic Mineral Product Manufacturing
327
Primary Metal Manufacturing
331
Fabricated Metal Product Manufacturing
332
Machinery, Computer, and Electronic Product
manufacturing
333, 334
Electrical Equipment, Appliance, and Component
Manufacturing
335
Transportation Equipment Manufacturing
336
Rail Transportation
482
Transit and Ground Passenger Transportation
485
Truck Transportation and Warehousing
484, 493
Support Activities for Transportation
473, 474, 478
4881xx, 4882xx, 4884xx,
4889xx
Utilities
2211xx
Wholesale Trade – Durable Goods
501, 503, 505,
506, 507, 509
423140, 423930, 423110,
4233xx, 4237xx, 4238xx,
Wholesale Trade – Nondurable Goods
514, 515, 516,
517, 518, 519
424930, 4244xx,
4246xx, 4247xx, 4248xx,
Building Materials, Hardware, Garden Supplies Dealers
521, 523, 526
444
Food and Beverage Stores
445
Automotive Dealers and Gasoline Service Stations
441, 447
Food Services and Drinking Places
722
Rental and Leasing Services
735
5321xx, 5324xx
Repair and Maintenance
811192, 8111xx, 8112xx,
8113xx, 8114xx,
Ambulatory Health Care Services and Hospitals
806, 807
621, 910
Educational Services
6111xx, 6112xx, 6113xx,
6115xx
Museums, Historical Sites, and Similar Institutions
842
712
Chapter 3: Source Control Inventory Development, Updates, and Prioritization
April 2022
Source Control (Business/Site) Inspection Program Guidance Manual
The number of businesses/sites included in a jurisdiction’s source control inventory will drive the
number of annual inspections that should be targeted (Western Washington 2019-2024 Phase II
Permit, S5.C.8.b.iii.(b)):
(b)
The Permittee shall annually complete the number of inspections equal to
20% of the businesses and/or sites listed in their source control inventory…
Multiple types of inspections count toward meeting the annual target, including initial
inspections, follow-up compliance visits, initial inspections attempted but where entry was
denied, and business/site complaint response inspections. Each type of visit will count towards
the target number.
The NPDES Municipal Stormwater permits provide clarity on how responses to complaints are
addressed and whether a jurisdiction needs to complete inspections for all of the
businesses/sites included in their inventory (Western Washington 2019-2024 Phase II Permit,
S5.C.8.b.iii.(b) and (c)):
(b)
The Permittee may count follow-up compliance inspections at the same
site toward the 20% inspection rate. The Permittee may select which sites to
inspect each year and is not required to inspect 100% of sites over a 5-year
period.
(c)
Each Permittee shall inspect 100% of sites identified through credible
complaints.
(d)
Permittees may count inspections conducted based on complaints, or
when the property owner denies entry, to the 20% inspection rate.
An inventory (i.e., the estimate of the number of businesses/sites) will be needed to determine
the target number of inspections (20 percent) for that year.
Ecology allows the following for prioritizing site inspections (Western Washington 2019-2024
Phase II Permit, S5.C.8.b.iii.(b)):
Sites may be prioritized for inspection based on their land use category,
potential for pollution generation, proximity to receiving waters, or to address
an identified pollution problem within a specific geographic area or sub-basin.
Chapter 3: Source Control Inventory Development, Updates, and Prioritization
April 2022
Source Control (Business/Site) Inspection Program Guidance Manual
3.2. RECOMMENDED PROCESS
Recommended steps developing and updating a source control inventory can be found in
Figure 3.1 (the native Visio file provided as SCORL Supplemental Resource 3A can be modified
to match a jurisdiction-specific process) and are also described below. Development of these
steps was informed by a resource developed by Phase I jurisdictions (see SCORL Supplemental
Resource 3B) to document site list development and modification. Table 3.2 provides potential
sources of data for completing the inventory along with advantages and disadvantages of each.
To develop the source control inventory, the following steps are recommended:
Step 1: Develop Initial Inventory
o Use primary data sources (see Table 3.2) including complaint sites and businesses
listed by NAICS/SIC codes in Appendix 8 of the 2019-2024 NPDES Municipal
Stormwater permits to develop an initial inventory that meets the base
requirements in the permit (Tier 1: Permit-required Source Control Inventory).
o The first pass of data gathering for the inventory is “initial” because inventories
will require ongoing refinement, addition, deletion, correction, and updates as
new information is learned about each business during outreach and inspection
efforts (see Step 3).
Step 2: Refine Initial Inventory
o Review supplemental data sources (see Table 3.2) and incorporate if applicable.
Appendix 8 of the 2019-2024 NPDES Municipal Stormwater permits does not
necessarily address all potential pollutant-generating sites. For example, the
permit only requires multi-family (or home business) sites to be inspected on a
complaint-basis, but these sites can generate pollutants and may be beneficial to
include in the inventory regardless of complaint status.
o Additional businesses may also be added to the source control inventory (Tier 2:
Expanded Source Control Inventory) to address other local environmental goals.
o When developing and refining the inventory, permittees should document sites
that are excluded from their inventory such as the following examples:
Examples of Inventory Exclusions
● Sites (or site categories) that are determined (via desktop review, windshield survey, or inspection) as non-
pollutant generating.
● NPDES permitted sites within another permittee’s jurisdiction.
● Sites managed by Secondary Permittees.
● City/County-owned properties (already addressed under S5.C.7 Operations and Maintenance).
In some cases, rather than excluding a site from the inventory, permittees may
consider coordinating a partnership for coverage of the site, where applicable.
Chapter 3: Source Control Inventory Development, Updates, and Prioritization
April 2022
Source Control (Business/Site) Inspection Program Guidance Manual
See Partnering Opportunities to Consider for Prioritization in Section 3.3, covered
in more detail in Chapter 4: Developing a Business/Site Inspection Program.
Step 3: Update Inventory Based on New Data Sources (ongoing)
o Review and update the inventory (see Table 3.2) on an ongoing basis to refine
accuracy of the initial inventory developed in Steps 1 and 2, based on inspection
results.
o It may be beneficial to update the inventory once per permit term or more
frequently (e.g., continually or on an annual basis) to address new, relocated, or
closed businesses. Note: The 2019-2024 Phase I Permit requires an update once
per permit term (every 5 years); the Western Washington 2019-2024 Phase II
Permit does not specify a frequency for updating a source control inventory.
o See Chapter 6: Data Management and Recordkeeping for data management
recommendations for ongoing inventory updates. Due to the spatial elements
inherent in this step, a GIS-based approach is recommended.
Tier 1: Permit-required Source Control Inventory
Tier 2: Expanded Source Control Inventory (Optional)
Add all Multi-Family housing units (apartments,
condominiums) from parcel or other database
Review and Remove Exclusions
Sites (or site categories) that are determined as
non-pollutant generating
NPDES permitted sites within another permittee’s
jurisdiction
Sites managed by Secondary Permittees
City/County-owned properties
Set Target Number of Annual Inspections
Annually complete the number of inspections
equal to 20% of the businesses and/or sites
listed in inventory
Follow-up compliance visits, initial inspections
attempted but where entry was denied, and
business/site complaint response inspections
count towards meeting the annual target
Not required to inspect 100% of sites over a 5-
year period
Conduct Inspections
(see Chapter 4 for checklists
and other inspection
resources)
Step 3: Update Inventory Based on New
Data Sources (Ongoing)
Incorporate Inspectors’ field findings (revise SIC/
NAICS codes, etc.)
Update database to reflect changes in occupant
records (relocation, closure, etc.)
Correct for multi-parcel sites under one owner or
multi-site parcels that should be split (e.g.,
shopping malls)
Add new developments
Add new community reports/complaints
Add new water service accounts
Add new construction applications
Assess Partnership Opportunities
(see Chapter 4 regarding
coordination with Ecology or
neighboring jurisdiction(s))
Local business license database
Washington State DOR business license database
or CCFS advanced search
Local PPA Program
Water Quality Permitting and Reporting
Information System (PARIS)
Parcel or tax lot GIS data
Proprietary database purchased from third party
ESRI Business Analyst Web Application (Standard)
Community complaint records
Windshield Surveys
Check that the following are captured in your Inventory:
Locations with parking lots
Locations with dumpsters
Locations with visible signs of commercial activity
(advertising signs, bulk material storage)
Desktop/Database Analyses
Stormwater utility rate database
Private stormwater BMP/ facility database
Web Mapping Services (Google Street View,
Google Earth/Google Maps)
Web Searches
Prioritize Sites for
Inspection
(see Section 3.3)
Ongoing Outreach Activities
This information may be provided all at one time or spread
out over the permit term to allow for tailoring and
distribution of the information during site inspections (See
Chapter 7)
Early outreach can help to confirm (or eliminate)
businesses from the Inventory
Step 2: Refine Initial Inventory
Ongoing
Outreach
Activities
Ongoing Outreach Activities
Add sites to coordinate with other local environmental
goals, if applicable
Step 1: Develop Initial Inventory
Key
BMP = best management practice
CCFS = Corporations and Charities Filing System
DOR = Department of Revenue
ESRI = Environmental Systems Research Institute
GIS = Geographic Information System
NAICS = North American Industry Classification System
NPDES = National Pollutant Discharge Elimination System
PPA = Pollution Prevention Assistance
SIC = Standard Industrial…