Septic system requirements in Oregon
What landplan.io applies when it designs a septic system in Oregon: the system types allowed, tank sizes, setbacks and soil loading rates, with what septic products cost there.
Updated
Design a septic system for an address in Oregon
Reviewed landplan.io designs by Oregon's own rules, which our staff reviewed against the state's regulations. Last published 5 October 2026.
Septic systems allowed in Oregon
The system types landplan.io permits in Oregon:
- Standard Subsurface Systems
- Pressure Distribution System
- Drip systems
- Bottomless Sand Filter Systems
Septic tank size in Oregon
The daily design flow of a home: 75 gal/day per bedroom, at least 300 gal/day. The septic tank is sized from that flow:
| Daily design flow | Minimum tank |
|---|---|
| up to 240 gal/day | 1,000 gallons |
| 240 to 360 gal/day | 1,500 gallons |
| 360 to 600 gal/day | 2,000 gallons |
| 600 to 720 gal/day | 2,500 gallons |
| 720 to 840 gal/day | 2,750 gallons |
| 840 to 920 gal/day | 3,000 gallons |
| 920 to 1,040 gal/day | 3,250 gallons |
| Bedrooms | Daily design flow |
|---|---|
| 1 | 300 gal/day |
| 2 | 300 gal/day |
| 3 | 375 gal/day |
| 4 | 450 gal/day |
| 5 | 525 gal/day |
| 6 | 600 gal/day |
| 7 | 675 gal/day |
| 8 | 750 gal/day |
| 9 | 825 gal/day |
| 10 | 900 gal/day |
| 11 | 975 gal/day |
| 12 | 1,050 gal/day |
| 13 | 1,125 gal/day |
| 14 | 1,200 gal/day |
| 15 | 1,275 gal/day |
Septic setbacks in Oregon
| From | To | Distance |
|---|---|---|
| LineString | Groundwater Interceptors slope 3% or less | 20 Ft |
| LineString | Groundwater Interceptors slope greater than 3% Downgradient | 50 Ft |
| LineString | Groundwater Interceptors slope greater than 3% Upgradient | 10 Ft |
| LineString | Intermittent Streams | 20 Ft |
| LineString | Irrigation Canals Lined (watertight canal) : Downgradient | 25 Ft |
| LineString | Irrigation Canals Unlined: Downgradient | 50 Ft |
| LineString | Irrigation Canals Unlined: Upgradient | 25 Ft |
| LineString | Underground Utilities | 10 Ft |
| LineString | Water line | 10 Ft |
| Point | Groundwater Supplies and Wells | 100 Ft |
| Point | Springs Downgradient | 100 Ft |
| Point | Springs Upgradient | 50 Ft |
| Polygon | Existing Septic Component to be Abandoned | 5 ft |
These are the values the landplan.io design engine applies in Oregon. Confirm a design with the Oregon health department or your county's before you build.
Septic system costs in Oregon
| Product | Median | Typical range | Listings |
|---|---|---|---|
| Dual Septic Pump Tank | $2,100 | $1,500 – $2,700 | 5 |
| Septic Tank | $1,635 | $1,606 – $1,676 | 17 |
The Oregon price index: every product type, month by month.
Parcel data in Oregon
landplan.io has parcel boundaries for 36 of Oregon's 36 counties: the counties where 100% of the state's people live. Type an address there and the design starts from the parcel.
Septic companies, designers and jobs in Oregon
- Septic companies and distributors in Oregon (51)
- Septic designers in Oregon
- Septic design jobs in Oregon
Where the rules come from
The regulations and documents landplan.io's Oregon rules are read from:
- OAR 340 Division 71 - Onsite Wastewater Treatment Systems (current text from OARD) (OAR 340-071)
- OAR 340-071-0800 - Division 71 Tables (Table 1 Minimum Separation Distances and the other tables)
Septic rules by county in Oregon
- Baker County
- Benton County
- Clackamas County
- Clatsop County
- Columbia County
- Coos County
- Crook County
- Curry County
- Deschutes County
- Douglas County
- Gilliam County
- Grant County
- Harney County
- Hood river County
- Jackson County
- Jefferson County
- Josephine County
- Klamath County
- Lake County
- Lane County
- Lincoln County
- Linn County
- Malheur County
- Marion County
- Morrow County
- Multnomah County
- Polk County
- Sherman County
- Tillamook County
- Umatilla County
- Union County
- Wallowa County
- Wasco County
- Washington County
- Wheeler County
- Yamhill County
Questions
What septic systems are allowed in Oregon?
landplan.io permits these system types in Oregon: Standard Subsurface Systems, Pressure Distribution System, Drip systems and Bottomless Sand Filter Systems.
What size septic tank do I need in Oregon?
landplan.io sizes the septic tank in Oregon from the daily design flow: up to 240 gal/day: 1,000 gallons; 240 to 360 gal/day: 1,500 gallons; 360 to 600 gal/day: 2,000 gallons; larger flows need larger tanks. A home's design flow is 75 gal/day per bedroom, at least 300 gal/day.
How far must a septic system be from a well in Oregon?
landplan.io keeps these distances in Oregon: Point to groundwater supplies and wells: 100 Ft.
Does landplan.io have parcel data in Oregon?
Yes, for 36 of Oregon's 36 counties.