Septic and Onsite Wastewater Systems

The Dept. of Environmental Quality in conjunction with the Dept. of Commerce, provides the following guidance document on setbacks from decks to septic tanks and drain fields.

Information from the State Building Codes indicated that decks over 30 inches in height require a building permit and thus are a "structure". The following is a proposed guidance on setbacks from decks to septic tanks and drain fields.

Decks over 30 inches in height

Decks over 30 inches in height are required to have a 5 foot separation from the septic tank and a 10 foot separation from the drain fields. The measurements are to be taken from the location of the pier block or other supporting device. In the case of cantilevered decks, the tank and field may be partially under the deck as long as they are 5 feet from deck's supporting device(s).

For existing or new septic tanks that are not or not planned to be the required 5 feet from the deck structure but are accessible for pumping, the local Building Dept. official or a Professional Engineer may certify there are no structural problems associated with the reduced setback for consideration by the Agent.

Decks under 30 inches in height

Decks under 30 inches in height are not required to maintain a set back from the tank or drain fields to the deck structure, or it's supporting devices (ie pier blocks).

All decks

All decks, regardless of height, must:

1. not have any obstruction over, or within 5 feet of the tank that would impair pumping, and
2. be over or within 10 feet of a drain field if they cause the drain field to be inaccessible to a back hoe for repairs.

In the opinion of the Agent if the tank location appears to compromise the decks support structure, the agent should notify the local Building Department.

CDC 02/22/2005, rev. 05/04/2005, rev 06/29.05

Water Resources Department

For information, please visit Water Resources Department, or contact:

Amy Landvoigt
Oregon Water Resources Department
District 20 Watermaster
Amy.J.Landvoigt@oregon.gov
Phone: 503-312-1743
10722 SE Hwy 212
Clackamas, OR 97015

Field Services Regional Offices

Northwest Region
725 Summer Street NE, Suite A
Salem, OR 97301 map

A Time of Transfer evaluation must be performed by an Agent or a person who is qualified to perform the evaluation and is registered in accordance with ORS chapters 672 or 700 or has a current NSF International wastewater system inspector accreditation or other certification approved by the Department.

The following web links can help you find information on qualified Time of Transfer inspectors:

• Oregon Health Authority
  To do a query, click on this link and select "environmental health registration board."Then select your county and click "start search." A list of certified individuals will appear. To get additional information including contact phone numbers, click on the license number.
• NSF International
  Since this is a new requirement in Oregon there are currently few or no individuals with the NSF International Onsite Wastewater Inspector Accreditation in Oregon.
• List of DEQ and county offices
  These evaluations can also be done by applying for an existing system evaluation at your local county Environmental Health or regional DEQ office.

For more information on time of sale inspections, go to the Oregon Department of Environmental Quality.

For pre-construction stake out inspections, skip steps 1-3. Please make sure the stake out drawing has been submitted and call the IVR system for inspection.

1. Install the septic system as indicated on the construction detail sheet, but do not backfill the system.
2. Complete the Onsite Wastewater Installed Materials List and As-Built Form. Make sure the as-built drawing is signed by the installer of the septic system.
3. Fax to 503 742-4550 or email (PDF format to soilsconcern@clackamas.us) the Onsite Wastewater Installed Materials List, As-Built Form, Certificate of Existing System Decommissioning (if required), and Pump Receipt (if required) to 503-742-4599 before 6 a.m. of the day the inspection is requested.
4. Call the IVR inspection line at 503-742-4720 before 6 a.m. and follow the steps listed on the back of your permit/receipt.