Ecology's Index of interpretive and policy statements and Declaratory and Final Orders.

• AQP-POL-2022 Data Center Permitting
• AQP-GUI-2019 AERMOD APP Review
• AQP-GUI-2020 Simplified approach to AERSCREEN
• AQP-POL-2020 How to Apply 460 Standards
• AQP-POL-2019 Cancer Risk
• AQP-POL-2019 60-day preliminary determination
• AQP-POL-2019 Evaluating Equipment Replacement
• AQP-POL-2019 Evaluating Modification
• Fugitive Dust Control Plan and Best Management Practices for Cattle Feeding Operations (Oct. 2018)
• Guidance Document: First, Second, and Third Tier Review of Toxic Air Pollution Sources (Aug. 2015)
• Guidance on Washington State's Prevention of Significant Deterioration Permitting Program (Nov. 2017)
• Focus On New Source Review: Requirements for New Sources of Air Pollution (June 2011)
• Air Quality Program: Program Specific Guidelines 
• Memorandum: Determination of Application of MTCA Permit Exemption, RCW 70.105D.090 to Air Quality Program Permits
• Guidance on Permitting Emergency Generators (>500 – 2000bhp)
• Guidelines for Grain Elevators and Grain Terminals Eastern Washington Location
• Memorandum: Implementation of the Determination of Application of MTCA Permit Exemption, RCW 70.105D.090 to Air Quality Program Permits

• Better Brakes Law Policy Statement on Reporting Requirements for OESC friction material
• Marking of Original Equipment Service Contract Brakes (Jan. 8, 2018)

The Dam Safety program has statements related to the following topics:

• Dam Safety Program
• Dam construction permit process
• Dam construction inspection policies
• Dam safety compliance and enforcement
• Dam safety project operation
• Dam safety response to emergencies
• Inspection of existing dams

Dam Safety program

• Policy 5101 - Designation of state dam safety office (July 21, 1999)
• Policy 5102 - Applicability of dam safety policies and procedures (July 21, 1999)
• Policy 5103 - Applicability of policies to dams which are federally owned (July 21, 1999)
• Policy 5104 - Applicability of policies to non-federal dams which are licensed or exempted for hydropower by the Federal Energy Regulatory Commission (FERC) (July 21, 1999)
• Policy 5105 - Exemption of dams which are six feet or less in height (July 21, 1999)
• Policy 5106 - Multiple small dams in series (July 21, 1999)

Dam construction permit process

• Policy 5201 - Issuance of construction permit (July 21, 1999)
• Policy 5202 - Engineering approval of construction plans and specifications (July 21, 1999)
• Policy 5203 - Assessment and collection of fees for engineering review of construction plans and specifications and for construction inspections (July 21, 1999)
• Policy 5204 - Plan review requirements for construction change orders (July 21, 1999)
• Policy 5205 - Review of construction plans and specifications received after project construction (July 21, 1999)
• Policy 5206 - SEPA compliance as related to issuance of construction permit (July 21, 1999)

Dam construction inspection policies

• Policy 5301 - Inspection of construction work (July 21, 1999)
• Policy 5302 - Construction inspection plans by dam owners (July 21, 1999)

Dam safety compliance and enforcement

• Policy 5502 - Use of enforcement action when voluntary compliance is not forthcoming (July 21, 1999)

Dam safety project operation

• Policy 5601 - Operation and maintenance manuals and emergency action plans (July 21, 1999)
• Policy 5602 - Emergency spillway requirements at off-channel storage facilities (July 21, 1999)

Dam safety response to emergencies

• Policy 5701 - Emergency response procedures by dam safety section (July 21, 1999)
• Policy 5702 - Discretionary actions during emergency or exigency situations (July 21, 1999)

Inspection of existing dams

• Policy 5401 - Periodic inspection of existing dams - Federal Dams (July 21, 1999)
• Policy 5402 - Periodic inspection of existing dams - hydropower dams licensed or exempted by FERC (July 21, 1999)
• Policy 5403 - Periodic inspection of existing dams - Ecology sole regulatory agency (July 21, 1999)
• Policy 5404 - Frequency of periodic inspections  July 21, 1999)
• Policy 5405 - Dams constructed without prior DSO approval of plans and specifications (recent construction) (July 21, 1999)
• Policy 5406 - "Older" dams which were constructed many years ago without DSO approval of plans and specifications (July 21, 1991)
• Policy 5407 - Periodic inspections of metals mining tailings impoundments (July 21, 1999)

• Interim Policy for Prepreg Waste  (Dec. 31, 2018 – Dec. 31, 2021)
• Guidelines for Developing and Updating Local Hazardous Waste Plans (Feb. 2010)
• Policy 3-11 – Dangerous Waste Management Facilities: Late and/or Inadequate Applications for a Final Status Permit (Dec. 1996)
• Implementation Guidelines for Local Hazardous Waste Plans (July 1992)
• Household Hazardous Waste: Guidelines for Conducting Collection Events (Feb. 1989)
• Zoning Guidelines for Hazardous Waste Treatment and Storage Facilities (July 1987)

• Compliance Assurance Manual
• Standards and Practices for Economic Analysis

Procedure Manual for the Environmental Laboratory Accreditation Program (Sept. 2010)

• Washington State Clean Diesel Program and Volkswagen Settlement Grant Program: Ecology’s Electric Fire Apparatus Grant Program FY 2022-2023 Grants Announcement and Grant Guidelines (November 2022)
• 2022-23 SFY NEP Stormwater Strategic Initiative Funding Guidelines (September 2022)
• 2024 Freshwater Algae Grant Funding Guidelines (September 2022)
• 2024 Aquatic Invasive Plant Grant Funding Guidelines (September 2022)
• State Fiscal Year 2024 Funding Guidelines Water Quality Combined Funding Program (August 2022)
• Washington State Clean Diesel Program: Ecology’s Clean Diesel Grant Program 2022-2023 Grants Announcement and Grant Guidelines (July 2022
• Washington State Clean Diesel Program: Ecology’s Clean School Bus Grant Program 2022-2023 Grants Announcement and Grant Guidelines (June 2022)
• Tribal Consultation Grants for Climate Commitment Act Funding Decisions (June 2022)
• Tribal Carbon Offset Assistance Grant Program: 2022-23 (June 2022)
• Clean Diesel Program 2022-2023: Clean School Bus Grant Application Instructions (June 2022)
• Remedial Action Grant and Loan Guidance for the 2023–25 Biennium: Oversight Remedial Action Grants and Loans, Area-wide Groundwater Investigation Grants, and Safe Drinking Water Action Grants (Revised June 2022)
• Remedial Action Grant and Loan Guidance for the 2021–23 Biennium: Oversight Remedial Action Grants and Loans, Area-wide Groundwater Investigation Grants, Safe Drinking Water Action Grants (June 2022)
• EAGL Instructions for 2023–25 Remedial Action Grant & Loan Applications: Toxics Cleanup Program’s guidance for using Ecology’s Administration of Grants & Loans System (EAGL) to apply for Oversight Remedial Action Grants & Loans, Area-wide Groundwater Investigation Grants, Safe Drinking Water Action Grants (January 2022)
• 2022 Clean Water State Revolving Fund Emergency Funding Program Guidelines (December 2021)
• Washington State Clean Diesel Program: Ecology’s Electric School Bus Grant Program 2022-2023 (December 2021)
• 2021 Clean Water State Revolving Fund Emergency Funding Program Guidelines (November 2020)
• 2021–2023 Prevent Nonattainment (PNA) Grant Funding Application (October 2021)
• Rehabilitation of High Hazard Potential Dams Grant Program: Fiscal Year 2021 Funding Program Guidelines (October 2021)
• Water Banking Pilot Grants: 2021-2023 Funding Guidelines (October 2021)
• SFY 2023 Aquatic Invasive Plants Grant Guidlines (October 2021)
• Floodplains by Design Grants Funding Guidelines 2023-25 (October 2021)
• Clean Diesel Program, EPA DERA 2021: Funding Program Guidelines (October 2021)
• Air Quality Prevent Nonattainment Competitive Grants: 2021-23 Funding Guidelines (October 2021)
• 2022-23 Waste Reduction and Recycling Education Grants - Funding Guidelines (October 2021)
• Puget Sound Nutrient Reduction Grant Program Applicant Prep Tool (September 2021)
• 2021-2023 Puget Sound Nutrient Reduction Grant Program Funding Guidelines (September 2021)
• Streamflow Restoration Competitive Grants, 2022: Guidance for project applicants (September 2021)
• State Fiscal Year 2023 Funding Guidelines—Water Quality Combined Funding Program (August 2021)
• Clean Diesel Program 2022-2023: Clean Diesel Grant Application Instructions (July 2021)
• 2021-23 Municipal Stormwater Capacity-Building Grant Funding Guidelines (July 2021)
• 2021 Drought Response Grant Funding Guidance - Chapter 173-167 WAC (July 2021)
• Air Quality Local Partner Woodsmoke Reduction Grant Funding Guidelines 2021-23 (July 2021)
• Washington State Local Partner Core Operations Grant Funding Guidelines 2021-23 (July 2021)
• Funding Guidelines 2021–2023 Biennium: Oil Spill and Hazardous Materials Response and Firefighting Equipment Grants (May 2021)
• Municipal Stormwater Grants of Regional or Statewide Significance 2021-23 Funding Guidance (May 2021)
• Funding guidelines Floodplains by Design 2019-2021 Biennium (May 2021)
• Rehabilitation of High Hazard Potential Dams Grant Program Fiscal Year 2020, Funding Program Guidelines (April 2021)
• Shoreline Master Program Periodic Review Grants- 2021-23 Funding Guidelines (May 2021)
• Spills Coastal Protection Fund Grant Program 2021 Funding Guidelines (January 2021)
• State Fiscal Year 2022 Draft Water Quality Funding Offer List and Intended Use Plan (January 2021)
• Water Quality Program Aquatic Invasive Plant Grant Funding Guidelines (September 2020)
• Water Quality Program Freshwater Algae Grant Funding Guidelines (September 2020)
• Water Quality Program State Fiscal Year 2022 Funding Guidelines (August 2020)
• 2019-2021 Local Solid Waste Financial Assistance Guidelines (May 2020)
• Remedial Action Grants for Local Governments 2018-2021 Guidance (Revised April 2020)
• 2020-2021 Waste Reduction & Recycling Education Program Guidelines (April 2020)
• 2019-2023 NEP Funding Guidelines (March 2020)
• Washington State Volkswagen Settlement: Grants Announcement of Funds Available and Grant Guidelines to Purchase and Install Shore Power for Ocean Going Vessels in Washington, 2020-2023 (March 2020)
• 2020 Clean Water State Revolving Fund Emergency Funding Program Guidelines (January 2020)
• Grants Announcement of Funds Available and Grant Guidelines to Purchase and Install Electric Vehicle Charging Infrastructure along High-Traffic Transportation Corridors in Washington (January 2020)
• Terry Husseman Account (THA) Grants – 2020 Funding Guidelines (December 2019)
• Streamflow Restoration Competitive Grants, 2020: Guidance for project applicants (December 2019)
• Washington Volkswagen Settlement: Grants Announcement of Funds Available and Grant Guidelines to Replace Fossil Fuel Powered School Buses with All-Electric School Buses in Washington ( November 2019)
• Washington State Volkswagen Settlement Grants Announcement of Funds Available and Grant Guidelines to Purchase and Install Electric Vehicle Charging Infrastructure at State and Local Government-Owned Facilities (November 2019)
• Floodplains by Design Grant Funding Guidelines 2021-23 (October 2019)
• Funding Guidelines State Fiscal Year 2021 Water Quality Financial Assistance (August 2019)
• ​Streamflow Restoration Competitive Grants Guidance for Project Applicants - Draft for Public Comment (August 2019)
• 2019-21 Municipal Stormwater Capacity-Building Grants (July 2019)
• Program Guidelines Waste Reduction & Recycling Education (Revised July 2019)
• Shoreline Master Program Periodic Review Grants: 2019-21 Funding Guidelines (July 2019)
• Drought Response Grant Funding Guidance (June 2019)
• 2019-2021Public Participation Grants Program Guidelines (March 2019)
• Volkswagen Repowering/Replacing Transit Buses with All-Electric Transit Buses (March 2019)
• Washington State Volkswagen Settlement Grants Announcement of Funds Available and Grant Guidelines to Replace/Repower Fossil Fuel Powered Transit Buses with All-Electric Transit Buses (February 2019)
• Community Litter Cleanup Program: 2019-2021 Guidelines and Application Instructions (January 2019)
• Funding Guidelines 2020–2021 Biennium: Oil Spill and Hazardous Materials Response and Firefighting Equipment Grants (December 2018)
• Terry Husseman Account (THA) Grants – 2019 Funding Guidelines (December 2018)
• National Estuary Program Watershed Protection & Restoration Grant Program Addendum to the 2015 Solicitation for Proposals to Target Riparian Protection in Agricultural Landscapes of the Puget Sound Basin (July 2018)
• Streamflow Restoration Grants State Fiscal Year 2019 Interim Funding Guidelines (June 2018)
• Waste Reduction and Recycling Education Grant Program Guidelines (May 2018)
• Shoreline Master Program Periodic Review Grants Funding Guidelines (Revised March 2018)
• Program Guidelines: Local Solid Waste Financial Assistance (January 2018)
• Grant Proposal Requirements and Guidelines: Coastal Protection Fund Resource Damage Assessment (September 2017) 
• Funding Guidelines 2017-2019 Biennium: Oil Spill and Hazardous Materials Response and Firefighting Equipment (September 2017)
• Administrative Requirements for Recipients of Ecology Grants and Loans (Yellow Book) (August 2017)
• Municipal Stormwater Grants of Regional or Statewide Significance Funding Guidelines (July 2017)
• FY2017-19 Municipal Stormwater Capacity-Building Grants Funding Guidelines (July 2017)
• Terry Husseman Account (THA) Grants – Funding Guidelines (Revised June 2017)
• 2017-19 Community Litter Cleanup Program: Guidelines and Application Instructions (January 2017)
• Funding Guidelines FY 2017-2019 Floodplains by Design (October 2015)
• National Estuary Program Watershed Protection & Restoration Grant Program: Grant Guidelines for the 2015 Solicitation for Proposals (December 2015)
• Administrative Requirements for Recipients of Ecology Grants and Loans Managed in EAGL (March 2014)
• Administrative Requirements for Recipients of Ecology Grants and Loans — "The Yellow Book" (September 2005)

• Toxics Cleanup Program Interim Policy 730: Taking into Account Federal Human Health Surface Water Quality Criteria under MTCA ( Jan. 2021)
• Toxics Cleanup Program Policy 120A: Independent Remedial Actions (Dec. 2016)
• Toxics Cleanup Program Policy 130A: Coordination of MTCA and SEPA (Revised July 2004)
• Toxics Cleanup Program Policy 300: Site Discovery – Reporting Releases (Revised June 2004)
• Toxics Cleanup Program Policy 310A: Initial Investigations (Revised Dec. 2009)
• Toxics Cleanup Program Policy 310B: Creating or Changing the Name, Address, or Identification Number for a Facility or Site (Revised Oct. 2011)
• Toxics Cleanup Program Policy 330A: Listing of Sites on the Hazardous Sites List (Revised Oct. 2004)
• Toxics Cleanup Program Policy 330B: Removal of Sites from the Hazardous Sites List (Revised Oct. 2004)
• Toxics Cleanup Program Policy 340B: Managing TCP's Program Plan (Oct. 2008)
• Toxics Cleanup Program Policy 500A: Identification of Potentially Liable Persons (Revised May 2016)
• Toxics Cleanup Program Policy 520A: Consent Decrees (Revised April 2018)
• Toxics Cleanup Program Policy 520B: Interim Policy – Prospective Purchaser Agreements (Aug. 1994)
• Toxics Cleanup Program Policy 520C: De Minimis Consent Decrees (Revised Dec. 2016)
• Toxics Cleanup Program Policy 530A: Agreed Orders (Revised April 2018)
• Toxics Cleanup Program Policy 540A: Enforcement Orders (Revised April 2018)
• Toxics Cleanup Program Policy 550A: Cost Recovery (Revised Dec. 2017)
• Toxics Cleanup Program Policy 550C: Prepaid Cleanup Oversight (June 2006)
• Toxics Cleanup Program Policy 560B: Granting Mixed Funding for LUST Cleanups (Oct. 2017)
• Toxics Cleanup Program Policy 600A: Site Register Publication (Revised April 2008)
• Toxics Cleanup Program Policy 710A: Permit Exemptions for Remedial Actions under MTCA (Revised Nov. 2015)
• Toxics Cleanup Program Policy 800A: Property Access (Feb. 1991)
• Toxics Cleanup Program Policy 800B: Information Access (Feb. 1991)
• Toxics Cleanup Program Policy 840: Data Submittal Requirements (Revised April 2016)
• Toxics Cleanup Program Procedure 320: Site Hazard Assessment and Ranking of MTCA Sites by Ecology Staff (Revised June 2004)
• Toxics Cleanup Program Procedure 321: Site Hazard Assessment of MTCA Sites by Local Health Districts/Departments (Revised June 2004)
• Toxics Cleanup Program Procedure 440A: Establishing Environmental Covenants under the Model Toxics Control Act (Revised Dec. 2016)
• Toxics Cleanup Program Procedure 440C: Releasing Environmental Covenants under the Model Toxics Control Act (Revised Dec. 2016)
• Toxics Cleanup Program Procedure 500A: Identification of Potentially Liable Persons (Revised May 2016)
• Toxics Cleanup Program Procedure 550A: Cost Recovery under a MTCA Order or Decree (Revised Feb. 2015)
• Toxics Cleanup Program Procedure 550B: Property Liens under RCW 70.105D.055 (July 2012)
• Toxics Cleanup Program Implementation Memo No. 2: Applicability of WAC 173-340-706 (Revised Sept. 2018)
• Implementation Memorandum #4: Determining Compliance with Method A Cleanup Levels for Diesel and Heavy Oil (June 2004)
• Implementation Memorandum #5: Collecting and Preparing Soil Samples for VOC Analysis (June 2004)
• Nematode Bioassay Protocol for Soil Toxicity Screening (Aug. 2004)
• Implementation Memorandum #7: Soil Moisture Corrected Reporting by EPA Method 8000C (Feb. 2008)
• Technical Memorandum #8: Natural Background for Dioxins/Furans in WA Soils (Aug. 2010)
• Technical Memorandum #9: Building Code Compliance for Factory Built Commercial Structures (May 2011)
• Implementation Memorandum #10: Evaluating the Human Health Toxicity of Carcinogenic PAHs (cPAHs) using Toxicity Equivalency Factors (TEFs) (April 2015)
• Implementation Memorandum #11: Dioxins, Furans, and Dioxin-Like PCB Congeners: Addressing Non-Detects and Establishing PQLs for Ecological Risk Assessments in Upland Soil (July 2015)
• Implementation Memorandum #12: When to Use EPA Method 1668 for PCB Congener Analyses (July 2015)
• Implementation Memorandum No. 13: Dioxins, Furans, and Dioxin-Like PCB Congeners: Ecological Risk Calculation Methodology for Upland Soil (July 2016)
• Implementation Memorandum No. 14: Updated Process for Initially Assessing the Potential for Petroleum Vapor Intrusion (March 2016)
• Implementation Memorandum No. 15: Frequently Asked Questions (FAQs)Regarding Empirical Demonstrations and Related Issues (June 2016)
• Implementation Memorandum No. 16: Developing Conditional Points of Compliance at MTCA Sites Where Groundwater Discharges to Surface Water (Revised Dec. 2017)
• Implementation Memorandum No. 18: Petroleum Vapor Intrusion (VI): Updated Screening Levels, Cleanup Levels,and Assessing PVI Threats to Future Buildings (Revised Jan. 2018)
• Implementation Memorandum No. 19: Gasoline and DieselSoil Concentrations Predicted to be Protective of UplandEcological Receptors (Aug. 2017)
• Implementation Memorandum No. 20: Frequently Asked Questions (FAQs) Regarding Model Remedy Implementation (March 2017)
• Implementation Memorandum No. 21: Frequently Asked Questions (FAQs) Regarding Vapor Intrusion (VI) andEcology's 2009 Draft VI Guidance (Revised Nov. 2018)
• Implementation Memorandum No. 22: Vapor Intrusion (VI) Investigations and Short-Term Trichloroethene (TCE)Toxicity (Revised Oct. 2019)
• Interprogram Policy: Area of Contamination 
• Focus on Model Toxic Control Act Cleanup Regulation:Process for Cleanup of Hazardous Waste Sites (Revised Nov. 2007)
• Focus on: Washington’s Environmental Cleanup Law (Revised Nov. 2018)
• Focus on Site Register (Revised Sept. 2009)
• Private Right of Action (Revised Dec. 2002)
• Remedial Investigation Checklist (May 2016)
• Feasibility Study Checklist (May 2016)
• Cleanup Action Plan Checklist (May 2016)
• Adaptation Strategies for Resilient Cleanup Remedies: A Guide for Cleanup Project Managers to Increase the Resilience of Toxic Cleanup Sites to the Impacts from Climate Change (Nov. 2017) 
• Focus on Hazardous Sites List (Revised Aug. 2009)
• Focus on Washington Ranking Method (Revised Aug. 2009)
• Focus on Site Hazard Assessment (Revised Aug. 2009)
• Washington Ranking Method Scoring Manual (Revised April 1992)
• Site Hazard Assessment Guidance and Procedures for Washington Ranking Method (Revised April 1992)
• Toxicology Database for Use in Washington Ranking Method Scoring (Revised Nov. 2008)
• Focus on Developing Soil Cleanup Standards under the Model Toxics Control Act (Revised April 2005)
• Focus on Developing Ground Water Cleanup Standards under the Model Toxics Control Act (Revised April 2005)
• Focus on Developing Surface Water Cleanup Standards under the Model Toxics Control Act (Revised April 2005)
• Cleanup Levels and Risk Calculations (CLARC) under theModel Toxics Control Act 
• Workbook Tools for Calculating Soil and Ground Water Cleanup Levels Under the Model Toxics Control Act Cleanup Regulation: Users Guide for MTCATPH 11.1 and MTCASGL 11.0 (Revised Dec. 2007)
• MTCASGL 11.0: Workbook for Calculating Cleanup Levels for Individual Hazardous Substances 
• MTCATPH 11.1: Workbook for Calculating Cleanup Levels for Petroleum Contaminated Sites 
• Statistical Guidance for Ecology Site Managers (Revised Aug. 1993)
• Guidance on Sampling and Data Analysis Methods (Revised Jan. 1995)
• MTCAStat 97: Site Module 
• MTCAStat 97: Background Module 
• Natural Background Soil Metals Concentrations in Washington State (Oct. 1994)
• Draft Technical Document: Terrestrial Ecological Evaluations under the Model Toxics Control Act (Feb. 2019)
• Draft Guidance for Evaluating Soil Vapor Intrusion in Washington State: Investigation and Remedial Action (April 2018)
• Guidance for Remediation of Petroleum Contaminated Sites (Revised June 2016)
• Analytical Methods for Petroleum Hydrocarbons (Revised June 2013)
• Model Remedies for Sites with Petroleum Contaminated Soils (Revised Dec. 2017)
• Model Remedies for Sites with Petroleum Impacts to Groundwater (Revised Dec. 2017)
• Guidance on Remediation of Petroleum-Contaminated Ground Water by Natural Attenuation (July 2005)
• User’s Manual: Natural Attenuation Analysis Tool Package for Petroleum-Contaminated Ground Water (July 2005)
• Natural Attenuation Analysis Tool for Petroleum-Contaminated Ground Water –Package A: Workboo kwithout Groundwater Flow Model
• Natural Attenuation Analysis Tool for Petroleum-Contaminated Ground Water –Package B: Workbook with Groundwater Flow Model
• Sediment Cleanup User's Manual II (SCUM II) (Revised Dec. 2019)
• Wood Waste Cleanup: Identifying, Assessing, and Remediating Wood Waste in Marine and Freshwater Environments (Sept. 2013)
• Bellingham Bay Regional Background Sediment Characterization: Final Data Evaluation and Summary Report (Feb. 2015)
• Port Gardner Bay Regional Background Sediment Characterization: Final Data Evaluation and Summary Report (Dec. 2014)
• Lake Washington Area Regional Background: Data Evaluation and Summary Report (Feb. 2017)
• North Olympic Peninsula Regional Background Sedimen tCharacterization: Data and Evaluation Report (Feb. 2016)
• South Puget Sound Regional Background: Final Data Evaluation and Summary Report (May 2018)
• Agency Determination Checklist (Dec. 2017)
• Guidelines for Property Cleanups under the Voluntary Cleanup Program (Revised July 2015)
• Voluntary Cleanup Program (VCP): Guidance for the Expedited VCP Process (July 2020)
• Toxics Cleanup Program Policy 900: Underground StorageTank (UST) Enforcement (Sept. 1992)
• Toxics Cleanup Program Policy 920: Providing Public Participation in Underground Storage Tank (UST) Settlements (Sept. 1992)
• Toxics Cleanup Program Policy 930: Investigation of and Responses to Complaints of Underground Storage Tank (UST) Violations (Sept. 1992)
• Focus on Check Your Farm Tank … It May be Regulated (Revised Nov. 2004)
• Focus on Waste Oil Tanks (Revised Sept. 2003)
• Focus on Spent Antifreeze USTs (Dec. 2015)
• UST Tank Fee Increase in 2018 (March 2017)
• Focus on UST Fee Increase in 2020 (Feb. 2019)
• Focus on Preparing for an UST Inspection English (Revised Oct. 2018)  Korean (Revised Sept. 2013) 
• Focus on UST Technical Assistance Program (Revised Jan 2012)
• Focus on Delivery Prohibition or “Red Tagging” (Revised Nov. 2012)
• Focus on the New UST Secondary Containment Requirement (Aug. 2012)
• Frequently Asked Questions about Biodiesel in Underground Storage Tanks (Oct. 2003)
• Focus on UST Operator Training English (Revised July 2013); Korean (Revised April 2012)
• Focus on Emergency Signage Required for UST Sites (Revised June 2013)
• Focus on Automatic Tank Gauges for Underground StorageTanks (March 2005)
• Focus on UST Spills or Releases (Revised May 2016)
• Guidance for Site Checks and Site Assessments for Underground Storage Tanks (Revised April 2003)
• What to do if You Find a Leak or Spill from Your Underground Storage Tank (Nov. 2007)
• Focus on: Temporary Closure of USTs (Oct. 2018)
• Permanent Closure of USTs
• Frequently Asked Questions about Financial Responsibility for Underground Storage Tanks (Revised Sept. 2015)

Title and description​

• Interpretive Statement on Subdivision SEPA Exemptions (2023)
• Shoreline Master Program Periodic Reviews (2023)
• Shoreline Master Program Periodic Review deadlines (Aug. 2019)
• Shoreline Master Programs Handbook (Revised Dec. 2017)
• Reimbursement of permit decision legal expenses under RCW 43.21A.690 and 90.03.265 (Dec. 2000)

• Ground Water Monitoring Guidance for Solid Waste Facilities (July 1987)
• Guidelines for Reporting Imported Solid Waste (Jan. 1994)
• Moderate Risk Waste Fixed Facility Guidelines (Dec. 1995)
• Frequently Asked Questions about Moderate-Risk WasteCollection Facilities; Implementation of Chapter 173-350-360 WAC (Nov. 2003)
• On-Farm Composting of Livestock Mortalities (July 2005)
• Environmentally Sound Management and Performance Standards for Direct Processors (Nov. 2007)
• Guidelines for Developing and Updating Local Hazardous Waste Plans (Feb. 2010)
•  
• Guidelines for Development of Local Comprehensive Solid Waste Management Plans and Plan Revisions (Feb. 2010)
• Acceptable Uses for Recycled Asphalt Roofing in Washington State (Revised Jan. 2011)
• Frequently Asked Questions about Assessment Monitoring for Chapter 173-351 WAC Landfills (Revised March 2012)
• Odor Prevention, Management/Mitigation Plan Requirements (Aug. 2013)
• Preparing for Termination of Post-Closure Activities at Landfills Closed Under Chapter 173-304 WAC (Revised April 2014)
• Guidelines for Operating an Anaerobic Digester Exempted From Solid Waste Handling Permit (Revised Feb. 2014)
• Guidance for Monitoring at Landfills and Other Facilities Regulated Under Chapters 173-304, 173-306, 173-350, and 173-351 WAC (Revised Dec. 2018)
• Manufacturer Plan Guidance for the Photovoltaic Module Stewardship Program (July 2019)
• Managing Nitrogen from Biosolids (June 1999)
• Biosolids Management Guidelines for Washington State (Revised July 2000)

• Biosolids Job Alike Group Decision Record: Large Onsite Septic Systems and Applicability to WAC 173-308 
• Organics Job Alike Group Decision Record: Achieving Class B for Pathogens Status via the Seven Samples Alternative
• Organics Job Alike Group Decision Record: Adding Persons to a Biosolids Interested Parties List and Notifying Persons on the List 
• Organics Job Alike Group Decision Record: Out of State Biosolids-Should they be held to the same beneficial use standards? 
• Organics Job Alike Group Decision Record: Biosolids Beneficial Use Facilities Proposing Sites in Different Regions 
• Organics Job Alike Group Decision Record: Policy on One Biosolids Permit Per Land Application Site 
• Organics Job Alike Group Decision Record: Soil Sampling at Septage Sites
• Organics Job Alike Group Decision Record: Using WAC 173-308-310(22) to Approve Transfers of Biosolids on Land 
• Organics Job Alike Group Decision Record: Policy on Mixing Exceptional Quality Biosolids 
• Organics Job Alike Group Decision Record: Application of Biosolids/Septage to Frozen or Snow Covered Ground 
• Waste 2 Resources Program Facilities Implementation Team **Discussion Thread/Decision Record**: Biodiesel Filtercake as an Acceptable Feedstock for Permit Exempted Anaerobic Digesters. 
• Waste 2 Resources Program Facilities Implementation Team (FIT)**Discussion Record**: Are anaerobic digesters subject to permitting, design and operating standards as a tank or surface impoundment under WAC 173-350-330 or are they conditionally exempt as recyclers under WAC 173- 350-210? 
• Waste 2 Resources Program Facilities Implementation Team (FIT) **Discussion Thread**: Are facilities handling liquids squeezed from food waste, but not otherwise handling the food waste, subject to WAC 173-350?

• Ecology Spill Drill Evaluation Checklist 
• Ecology Self Certified Spill Drill and Exercise Evaluation Checklist 
• Ecology Out of State Credit Spill Drill and Exercise Evaluation Checklist 
• Spills Program CORE Procedure - CORE 10E: Covered Vessel Incidents and Managing Captain of the Port Orders
• Guidance on covered vessels/facilities needing contingency plans
• Focus on Pre-Booming Requirements, Alternative Measures and Equivalent Compliance for Vessels Delivering Oil 
• Focus on Pre-Booming Requirements, Alternatives Measures and Equivalent Compliance for Oil Handling Facilities 
• Fishing Vessel Boarding Checklist 
• Washington State Accepted Industry Standards for Cargo & Passenger Vessels 
• Cargo and Passenger Vessel Boarding Checklist - Full Version 
• Cargo and Passenger Vessel Boarding Checklist - Short Form
• Washington State Accepted Industry Standards for Fishing Vessels
• Spills Program Prevention/Policy Procedure - PREV 1: Inspections
• Development of the WA State Oil Spill Compensation Schedule
• Guidelines for Determining Oil Spill Volume in the Field - Terminology, Ranges, Estimates and Experts
• Spills Program Cost Recovery - General Guidelines and Criteria
• RDA/CPF Executive Director Desk Manual
• Credit for Oil Recovery - Washington Oil Spill Compensation Schedule
• 2017 - 2019 Biennium Final Equipment Cache Funding Offer List
• State Fiscal Year 2017 Final Equipment Cache Funding Offer List
• Options for Responding to an Order for Reimbursement of Expenses (ORE)
• Spills Program CORE Procedure - CORE 12: Enforcement
• Revised Accepted Industry Standards, 1998-1999 C&P Vessel Inspection Advisory Committee
• Notice of Adoption, 1998-1999 Accepted Industry Standards for Cargo and Passenger Vessel Inspections (AIS)

• Dispute Resolution Related to Total Maximum Daily Loads (TMDLs) or Water Cleanup Plans – Water Quality Program Policy 1-25
• Stormwater Management Manual for Eastern Washington (Revised Aug. 2019)
• Criteria for Sewage Works Design (Orange Book) (Revised Feb. 2019) 
• Reclaimed Water Facilities Manual: The Purple Book (Revised Feb. 2019)
• Water Quality Policy 1-11 Chapter 1: Washington's Water Quality Assessment Listing Methodology to Meet Clean Water Act Requirements (Revised Nov. 15, 2018)
• Washington State’s Marine Dissolved Oxygen Criteria: Application to Nutrients – Understanding the Purpose and Application of the Criteria in the Surface Water Quality Standards (Revised Aug. 2018)
• Water Quality Permit Writer’s Manual (Revised July 2018)
• Whole Effluent Toxicity Testing Guidance and Test Review Criteria (Revised June 2016)
• Application of Water Quality Criteria in Brackish Waters (June 2015)
• Washington's Water Quality Management Plan to Control Nonpoint Sources of Pollution (Revised July 2015)
• Stormwater Management Manual for Western Washington, as amended in December 2014 (The 2014 SWMMWW) (Dec. 2014)
• Vehicle and Equipment Washwater Discharges/Best Management Practices Manual (Revised Nov. 2012)
• Water Quality Program Guidance Manual: Supplemental Guidance on Implementing Tier II Antidegradation (Sept. 2011)
• Water Quality Program Guidance Manual: Procedures to Implement the State’s Temperature Standards through NPDES Permits (Revised Oct. 2010)
• Water Quality Program Policy 1-11, Chapter 2: Ensuring Credible Data for Water Qualit Management (Revised July 2021)
• Implementation Guidance for Ground Water Quality Standards (Revised Oct. 2005)
• Water Quality Certifications for Existing Hydropower Dams: Guidance Manual (Revised April 2005)
• State Requirements for Submission of Engineering Reports and Plans for Industrial Wastewater Treatment Facilities (Jan. 2005)
• Guidance on Land Treatment of Nutrients in Wastewater, with Emphasis on Nitrogen (Nov. 2004)
• Information Manual for Treatment Plant Operators (Feb. 2004)
• Guidelines for the Preparation of Engineering Reports for Industrial Wastewater Land Application Systems (May 1993)

• Water Resources Program Policy: Defining and Delineation of Water Sources – Policy 2010 (Feb. 2007)
• Water Resources Program Policy: Policy for the Diversion or Withdrawal of Saltwater – Policy 1015 (Dec. 1994)
• Water Resources Program Policy: Policy for Conveying Stockwater Away from Streams To Protect Water Quality– Policy 1025 (Dec. 1994)
• Water Resources Program Policy: Permits for Short-Term Water Use – Policy 1037 (Sept. 1992)
• Water Resources Program Policy: Emergency Water Source Authorization – Policy 1045 (Sept. 2006)
• Water Resources Program Policy: Water Right Permits for Fire Fighting or Protection – Policy 2015 (March 2008)
• Water Right Procedure: Procedure for Notification of Water Right Actions to the Department of Revenue – Procedure 1130 (Oct. 2004)
• Water Resources Program Policy and Interpretive Statement: The Relinquishment, Rescission, and Abandonment of Water Rights – Policy 1060 (Dec. 2019)
• Interim Guidance for Determining Net Ecological Benefit for streamflow restoration planning and mitigation pilots (June 2018)
• ESSB 6091 Recommendations for Water Use Estimates (Revised June 2018)
• ESSB 6091 Initial Policy Interpretations (March 2018)

Administration of water rights

• Policy 1000 - Water Rights Processing Policy (March 2015)
• Procedure 1000 - Water Rights Processing Procedures (Revised March 2015)
• Policy 1017 - Policy Regarding Collection of Rainwater for Beneficial Use (Oct. 2009)
• Policy 2025 - Policy/Interpretive Statement on When to Perform a Maximum Net Benefits Analysis (Jan. 2005)
• POL 2050 - Policy and Interpretive Statement on Reservations of Water for Future Uses of the John Day-McNary Pools Reach of The Columbia River  (Aug. 2019)
• POL 2094 - Streamflow Restoration Policy and Interpretive Statement (July 2019)
• Final Guidance for Determining Net Ecological Benefit (July 2019)

Water right changes or transfers

• Policy 1200 - Evaluation of Changes or Transfers to Water Rights (Revised Nov. 2014)
• Policy 1210 - Policy for the Evaluation of Changes to Enable Irrigation of Additional Acreage or the Additon of New Purposes of Use to Existing Water Rights (Revised April 2018)
• Policy 1280 - Development Schedules for Water Right Changes and Transfers (April 2015)
• 2003 Municipal Water Law Interpretive and Policy Statement (May 2012)

Water use associacted with heat pumps

• Policy 2020 - Priority Processing of Heat Pump Applications  (April 20, 2018)