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Septic Systems
On-Site Wastewater Treatment Systems
An On-Site Wastewater Treatment System (OWTS), commonly known as a septic system, treats sewage on an individual’s property in the ground. Septic systems are installed on properties that cannot be served by publicly-owned wastewater collection and treatment systems which move sewage away from properties. Proper site evaluation, system selection and layout, installation, inspections and maintenance are essential in the onsite treatment of sewage.
On-Site Wastewater Treatment Requirements
Tri-County Health Department regulates all OWTS in Adams, Arapahoe, and Douglas counties and the program includes:
- Issuance of permits to install, repair, expand, use, or operate a system
- Plan review, site evaluation(s) before installation, final inspection(s) after installation, and certification before the system is put into use
- Investigation of malfunctions of systems
- Enforcement
Education and Care
- Septic Care & Maintenance Guidelines / Spanish
- Recommendations for Selecting a Septic Professional
- Standing Water in Standpipes / Spanish
- Vegetation Over Absorption Areas
- EPA SepticSmart
- Financial Assistance for OWTS Repairs
- RV Wastewater and OWTS
- Homeowner OWTS Maintenance Video
- Homeowner OWTS Demo Video
- Septics 101: A Guide to Septic System Maintenance
Site and Soil Evaluators and Designers
- Field Book For Sampling and Describing Soils - Natural Resources Conservation Service
- Mound Systems
- Distribution Networks
- Natural Resources Conservation Service Web Soil Survey
- EPA Onsite Wastewater Treatment Systems Manual - EPA
- Clarification Regarding the term “Infiltrative Surface” - CDPHE
- Clarification Regarding Soil Replacement - CDPHE
- Clarification for Determining the Number of Chamber Units in OWTS Design Under Regulation 43 - CDPHE
- Clarification on Required Setbacks from On-Site Wastewater Treatment Systems to Wells or Cisterns - CDPHE
- Vertical Isolation & Media Depth Chart & Explanation - CDPHE
- Soil Texture-LTAR-Triangle Chart
- Evapotranspiration On-Site Wastewater Treatment System Sand Media Policy
- Evapotranspiration Guidance Manual
- Evapotranspiration Design Spreadsheet - ET99
- Evapotranspiration Design Spreadsheet - ET99PEAK
- Evapotranspiration Design Spreadsheet - ETAVG3
- CDPHE Mound Guidance Document
- NDDS Install Video
Regulation, Applications, and Forms
- Regulation No. 0-17 (Effective October 1, 2017) and Summary of Changes
- Shallow Waste Disposal System/Well Inventory Request Form - Environmental Protection Agency (EPA). Required for commercial systems.
A septic permit is required for new installations, expansions, and repairs (with some exceptions). To obtain a permit, the following will be required: completed permit application, payment of permit fee, soil investigation and design document. Tri-County can accept permit applications at our Environmental Health Offices, or via email at: EHWebFillableForms@tchd.org. Tri-County staff will then review the information and make a site visit. If the application, engineer design (if applicable), design document and site meet our requirements, Tri-County will issue a permit to construct or repair an OWTS. Tri-County may require additional information depending on the conditions at the site. After the system is constructed (but before it's covered with soil) or is repaired, Tri-County staff will make a final site visit to ensure the work was completed per the OWTS Regulations. A Use Permit will be issued when the system is approved.
- Application for a Septic Permit - Fillable Form
- Directions to Property - Fillable Form
- OWTS Record Drawing
- OWTS Record Drawing Example
- Percolation Test Summary and Data Form
- Soil Profile Test Pit Log
- Site Evaluation and Design Document Checklist
- Conventional OWTS Design Worksheet - Fillable Form
- Application to Install a Lift Station
- Example Site Plan
- Tank Replacement Worksheet
- Variance Application
- Dosing and Pressure Dosing Design Checklist
A “Use Permit” expressly authorizes the use of a septic system. The most common circumstances that require obtaining or renewing a “Use Permit” include the sale or change of ownership of a property, change in use of the property (i.e., a residence is changed to a business), additional bedrooms added, or a separate “modular” home added. Tri-County can accept permit applications at our Environmental Health Offices, or via email at: EHWebFillableForms@tchd.org. For more information review the Use Permit Questions and Answers document below.
- OWTS Use Permit Questions & Answers - English
- OWTS Use Permit Questions & Answers - Spanish
- Application for a Septic Use Permit - Fillable Form
- Certified Use Permit Inspectors (Search Engine)
- Use Permit Inspection Form
- Use Permit Inspection Form Guide
- Use Permit Repair Verification Form
- Agreement to Forego Expansion of an OWTS
- Agreement to Repair a Septic
Finding Septic Professionals
Septic System Installers / Contractors
A person or company installing or repairing an On-Site Wastewater Treatment System in Adams, Arapahoe, or Douglas County must be licensed with Tri-County Health Department. To obtain a license, Tri-County must receive a completed application, affidavit of citizenship, and license fee. In addition, the applicant must take and pass the system’s contractor exam. The exam covers various sections of the Onsite Wastewater Treatment System Regulation and you can take an exam at one of our four Environmental Health offices during business hours. The license is valid from January 1 to December 31 and must be renewed every year. If your license is not renewed by January 31, then you will be required to retake and pass the exam.
Septic Tank Cleaners / Pumpers
A septic system cleaner / pumper must be licensed with Tri-County Health Department. To obtain a license, Tri-County must receive a completed application, affidavit of citizenship, and a license fee. The license is valid from January 1 to December 31 and must be renewed every year. Cleaners / Pumpers must also maintain a Septic Cleaners Log.
- How to Select a Septic Professional
- List of Septic Engineers
- List of Licensed Installers
- List of Licensed Cleaners / Pumpers
- List of Higher Level Treatment Inspectors
- Certified Use Permit Inspectors (Search)
- NAWT Certificate Renewal Information
Septic System Installers / Contractors
A person or company installing or repairing an On-Site Wastewater Treatment System in Adams, Arapahoe, or Douglas County must be licensed with Tri-County Health Department. To obtain a license, Tri-County must receive a completed application, affidavit of citizenship, and license fee. In addition, the applicant must take and pass the system’s contractor exam. The exam covers various sections of the Onsite Wastewater Treatment System Regulation and you can take an exam at one of our four Environmental Health offices during business hours. The license is valid from January 1 to December 31 and must be renewed every year. If your license is not renewed by January 31, then you will be required to retake and pass the exam.
Septic Tank Cleaners / Pumpers
A septic system cleaner / pumper must be licensed with Tri-County Health Department. To obtain a license, Tri-County must receive a completed application, affidavit of citizenship, and a license fee. The license is valid from January 1 to December 31 and must be renewed every year. Cleaners / Pumpers must also maintain a Septic Cleaners Log.