The following information is offered to assist you in planning your LOSS project and complying with regulatory requirements.
Rules and Regulations
- Chapter 246-272B WAC - Large On-site Sewage Systems Regulations
- Fees and Billable Hours
- Statutory Authorities: RCW 43.20.050, 43.70.110; 43.70.250, 70A.115, and Chapter 246-272-3000 WAC
Best Management Practices, Tech Tips, Fact Sheets, and Frequently Asked Questions
Best Management Practices
- Best Management Practice Explanation Form (PDF)
- Commercial Kitchens (PDF)
- Disposal of Pharmaceuticals (PDF)
- Kitchen Waste (PDF)
- Marinas (PDF)
- RV Parks (PDF)
- Schools (PDF)
Tech Tips
- How to Calculate Your Wastewater Flows Using Your Dose Counter (PDF)
- How to Calculate Your Wastewater Flows Using Your Elapsed Time Meter (PDF)
- Sampling Effluent in a LOSS (PDF)
- Wildfires / Water Outage / Power Outage (PDF)
- Before, During, and After a Flood (PDF)
Fact Sheets
- Do's and Don'ts of Septic System Care (PDF)
- Drainfield Care for LOSS (PDF) - Fact sheet discusses protecting the drainfield and reserve areas.
- Drainfield Reductions for LOSS (PDF) - Fact sheet helps clarify when reductions in drainfields are appropriate.
- Enforcement Process for LOSS (PDF) - Outlines the steps taken when a LOSS is not in compliance with state rules.
- Signs of Septic System Failure or Malfunction (PDF) - A failed or malfunctioning LOSS is a risk to human and animal health and can pollute the environment.
- Cross Reference: Health & Ecology, Large On-site Sewage System (LOSS) Documents (PDF) - A comparison of LOSS submittal requirements for the Department of Health and the Department of Ecology.
- Glossary of Terms (LOSS) (PDF)
- Guidelines for Test Pit Construction for On-site Sewage Systems (PDF)
- Large On-site Sewage System Online Payment Guide - An invoice must exist in order to make a LOSS payment online.
Operating Permit Renewal Forms
An annual operating permit renewal application is mailed in advance to each system by Department of Health.
- Flowchart of the LOSS Renewal Process (PDF)
- Annual Maintenance and Monitoring Report forms for LOSS:
- Operating Permit expires March 31 (Word)
- Operating Permit expires September 30 (Word)
Operating Permit for Existing LOSS: First Application
- Existing System Review and Operating Permit Process Flowchart (PDF) for existing Large On-site Sewage Systems (LOSS) without a DOH permit.
- Existing System Questionnaire (Word) for existing Large On-site Sewage Systems without a DOH Permit.
- Operating Permit Application (Word)
Designing and Building a New LOSS or Modifying an Existing LOSS
- Flowchart of the Large On-site Sewage System (LOSS) New Project Review & Approval Process (PDF)
- Flowchart of the Large On-site Sewage System (LOSS) Operating Permit & Approval to Construct Process (PDF)
- Sustainable Infrastructure for Small System Public Services - A Planning and Resource Guide (PDF)
- Project Submittal form for Large On-site Sewage System (LOSS) (Word) AKA Application for a New LOSS or Modification to an Existing LOSS
- Predesign Report Requirements, Large On-site Sewage System (LOSS) (PDF)
- Site Evaluation and Environment Review
- Guidelines for Test Pit Construction for On-site Sewage Systems (PDF)
- Engineering Report Checklist (PDF)
- Plans & Specifications Checklist (PDF)
- Operating Permit Application (Word)
- Public Notice Requirements for LOSS greater than 14,500 gallons per day
- Construction Completion Report for Large On-Site Sewage System (LOSS) (Word)
- Fact Sheet about Large On-site Sewage System (LOSS) Drainfield Reductions (PDF)
- Model Operation and Maintenance Manual (Word)
- Monitoring and Reporting Plan Manual (Word)
Environmental Review Forms and Guidance
- Guidelines for Test Pit Construction for On-site Sewage Systems (PDF)
- Monitoring and Reporting Plan Manual (Word)
- Monitoring Report Cover Sheet (Excel) - This form must be submitted along with your lab reports.
- Soil & Site Inspection Guidance - under development
- Search for an Accredited Laboratory - Washington State Department of Ecology website
- Site Risk Survey for Large On-site Sewage System (LOSS) (PDF)
- Level 1 Nitrate Balance Instructions (PDF)
- Level 1 Nitrate Balance Spreadsheet (Excel)
Inspecting and Evaluating Existing LOSS
- Inspection, Schematic, and Engineering Evaluation Guidance for Existing Large On-site Sewage Systems (Word)
- System Abandonment Report (PDF) - Large On-site Sewage System (LOSS)
- Infiltration and Inflow can be Costly - good article in the Spring 1999 "Pipeline" publication, including helpful tips to find and resolve.
LOSS Management
- Management of Large On-site Sewage Systems (LOSS) (PDF) - Guidelines that set forth the minimum information to be included in any LOSS Management Plan.
- Search for an Accredited Laboratory - Washington State Department of Ecology
Related Resources
- Criteria for Sewage Works Design (Orange Book) - Guide for the design of sewage collection, treatment, and reclamation systems. Developed and published by Washington State Department of Ecology.
- Glossary of Terms (LOSS) (PDF)
- How to Hire a Professional Engineer (PDF)
- Pressure Distribution Systems (RS&G) (PDF)
- Cross Reference: Health & Ecology, Large On-site Sewage System (LOSS) Documents (PDF) - A comparison of LOSS submittal requirements for the Department of Health and the Department of Ecology.
- Search for an Accredited Laboratory - Washington State Department of Ecology
More Resources
Wastewater Forms and Publications
Contact Wastewater Program Staff