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Septic System FAQs

How do I get a permit to build or repair an on-site wastewater treatment system (OWTS)?

An On-site Wastewater Treatment System (OWTS) permit is required for new installations, expansions, and repairs (with some exceptions). To obtain a permit, the following will be required for new systems/new soil treatment areas (STA’s):

  • Completed permit application
  • Payment of permit fee
  • System design
  • Soil information, test pit logs, and percolation tests (if used)
  • Site plan

Environmental Health staff will then review the information and make a site visit. If the application, design (if applicable), and site meet our requirements, we will issue a permit to construct, expand or repair the OWTS.

A Colorado Licensed Professional Engineer must design a system if any of the following occur:

  • The following soil types are identified within 4 feet below the depth of the proposed soil treatment area (STA): 0, 3A, 4, 4A, 5, R-O, R-1, R-2
  • Treatment levels TL2, TL2N, TL3, and TL3N as specified in tables 10 and 11 of Regulation 22-01 groundwater, bedrock, or other limiting layer is present within 4 feet below the depth of the proposed STA
  • The ground slope at the area of the proposed STA is greater than 20%
  • The proposed system is a commercial system
  • The proposed system utilizes pressure distribution

How do I get a Use Permit?

Review our Use Permit FAQs and visit our On-Site Waste Treatment System page for more information and related forms.

Who can perform Use Permit inspections?

Use permit inspections must be completed by a third-party Use Permit Inspector, certified by the National Association of Wastewater Technicians (NAWT). These types of inspectors do not work for Douglas County.

I am selling my property and need to get my waste water system certified. What should I do?

The seller of the property is required to obtain a use permit prior to the sale of the property.  For more information visit our Use Permit FAQs.

What is the minimum lot size for an OWTS?

Douglas County does not have a minimum lot size requirement. Local planning agencies do have minimum lot sizes in their zoning codes. They typically recommend a minimum of one acre for lots supplied by central water and 2.5 acres for lots with wells.

How often do I need to pump my septic tank?

The Douglas County Health Department requires septic tanks to be inspected every four years and pumped when scum and sludge accumulate to greater than 25% of the effective volume of the tank. Dosing tanks shall be inspected and pumped if sludge accumulation is observed.

If your OWTS receives higher than average use as determined by your licensed cleaner, you may want to consider a more frequent pumping interval. All pumping and evaluation of septic tanks should be done by a licensed cleaner. For more information, please visit our Septic System Education and Care page.

Will I be able to irrigate or have horses where my Soil Treatment Area (STA) is located?

We recommend that an STA be left largely untouched by homeowners. Horses or other livestock should not be placed on an STA because compaction of the soils may occur causing premature failure of your absorption area. Irrigated landscaping is not recommended, since it has the possibility to saturate an STA, causing the septic system to fail prematurely. You may consider planting buffalo grass or other natural grasses which do not require irrigation. Mow any grasses planted on the STA area regularly.

Can I install a bathroom in a garage, barn, etc., and connect it to my existing OWTS?

We generally allow the connection of bathrooms in buildings that are not dwellings to the existing septic system, provided the owner notifies the Douglas County Health Department in advance and the connection is approved. An inspection of the new plumbing and payment of applicable fee(s) are required. Prior to final approval, the existing recorded drawing of the system must also be amended to show new buildings and plumbing. For more information, contact our Environmental Health office prior to starting your project.

I am unsure where my OWTS is located. Do you have records of my system?

Locate septic permit records using the OWTS Permit Map where you can also search by address or owner name. In some instances, Douglas County may not have received historical permits from the Tri-County Health Department. If a record is not found, please contact Douglas County Environmental Health at 720-906-4886 or email [email protected]. It may be necessary to contact a licensed installer or a certified Use Permit inspector or surveyor to locate your system.

I accidentally damaged some components of my septic system. Who should I call to inspect and repair the damage? Do I need a permit?

If an OWTS is damaged, it is best to have the system evaluated by a licensed septic contractor. If the damage is relatively minor, such as damage to a single pipe or chamber, it likely will not require a permit, but the repair will need to be completed by a licensed contractor. All repairs will need to be inspected by DCHD prior to being covered. Inspection fees may apply. If the damage is more extensive, such as damage to the tank or extensive damage to the soil treatment area (STA), it may require a repair permit. Please consult with your contractor and Douglas County Health Department Environmental Health staff.