340-071-0400 Geographic Area Special Considerations. (1) General North Florence Aquifer, North Florence Dunal Aquifer Area, Lane County. (a) Within the area described in paragraph (b) of this section, an agent may approve sites or issue construction-installation permits for new onsite systems under either of the following circumstances: (A) The lot and proposed system comply with all rules in effect at the time the site is approved or the permit is issued. (B) The lot and proposed system comply with paragraph (A) of this subsection except for the projected daily sewage loading rates, and the agent determines the system in combination with all other previously approved systems owned or legally controlled by the applicant will not contribute to the local groundwater more than 58 pounds of nitrate-nitrogen per year per acre owned or controlled by the applicant. (b) Paragraph (a) of this section applies to the following area designated the General North Florence Aquifer of the North Florence Dunal Area and defined by the hydrologic boundaries identified in the June 1982, 208 North Florence Dunal Aquifer Study. The area is bounded on the west by the Pacific Ocean; on the southwest and south by the Siuslaw River; on the east by the North Fork of the Siuslaw River and the ridge line at the approximate elevation of four hundred (400) feet above mean sea level directly east of Munsel Lake, Clear Lake, and Collard Lake; and on the north by Mercer Lake, Mercer Creek, Sutton Lake, and Sutton Creek and includes all or portions of T17S, R12W, Sections 27, 28, 33, 34, 35, 36, and T18S, T12W, sections 1, 2, 3, 4, 9, 10, 11, 12, 13, 14, 15, 16, 22, 23, 24, 25, 26, 27; W.M., Lane County, except that portion defined as the Clear Lake Watershed, which is the area beginning at a point known as Tank One, located in Section One, Township 18 South, Range 12 West, of the Willamette Meridian, Lane County, Oregon: run thence S. 67° 50' 51.5" E. 97.80 ft. to the True Point of Beginning; run thence S. 05° 40' 43.0" W. 1960.62 ft. to a point; run thence S. 04° 58' 45.4" E. 1301.91 ft. to a point; run thence S. 52° 44' 01.0" W. 231.21 ft. to a point; run thence S. 15° 20' 45.4" E. 774.62 ft. to a point; run thence S. 31°44' 14.0" W. 520.89.ft. to a point; run thence S. 00° 24' 43.9" W. 834.02 ft. to a point; run thence S. 07° 49' 01.8" W. 1191.07 ft. to a point; run thence S. 50° 26' 06.3" W. 731.61 ft. to a point; run thence S. 02° 51' 10.5" W. 301.37 ft. to a point; run thence 36° 37' 58.2" W. 918.41 ft. to a point; run thence S. 47° 12' 26.3" W. 1321.86 ft. to a point; run thence S. 72° 58' 54.2" W. 498.84 ft. to a point; run thence S. 85° 44' 21.3" W. 955.64 ft. to a point; Which is N. 11° 39' 16.9" W. 5434.90 ft. from a point known as Green Two (located in Section 13 in said Township and Range); run thence N. 58° 09' 44.1" W. 1630.28 ft. to a point; run thence N. 25° 23' 10.1" W. 1978.00 ft. to a point; run thence N. 16° 34' 21.0" W. 1731.95 ft. to a point; run thence N. 06° 13' 18.0" W. 747.40 ft. to a point; run thence N. 03° 50' 32.8" E. 671.51 ft. to a point; run thence N. 59° 33'18.9" E. 1117.02 ft. to a point; run thence N. 59° 50' 06.0" E. 1894.56 ft. to a point; run thence N. 48° 28' 40.0" E. 897.56 ft. to a point; run thence N. 31° 29' 50.7" E. 920.64 ft. to a point; run thence N. 19° 46' 39.6" E. 1524.95 to a point; run thence S. 76° 05' 37.1" E. 748.95 ft. to a point; run thence S. 57° 33' 30.2" E. 445.53 ft. to a point; run thence S. 78° 27' 44.9" E. 394.98 ft. to a point; run thence S. 61° 55' 39.0" E. 323.00 ft. to a point; run thence N. 89° 04' 46.8" E, 249.03 ft. to a point; run thence S. 67° 43' 17.4" E. 245.31 ft. to a point; run thence S. 79° 55' 09.8" E. 45.71 ft. to a point; run thence S. 83° 59' 27.6" E. 95.52 ft. to a point; run thence N. 42° 02' 57.2" E. 68.68 ft. to a point; run thence S. 80° 41' 24.2" E. 61.81 ft. to a point; run thence S. 10° 47' 03.5" E. 128.27 ft. to the True Point of Beginning; and containing all or portions of T17S, R12W, Sections 35 and 36; and T18S, R12W, Sections 1, 2, 11 and 12; W.M., Lane County. (2) Lands overlaying the Alsea Dunal Aquifer. (a) Within the area set forth in paragraph (c) of this section, the agent may approve a site or issue a permit to construct a single onsite system on lots that were lots of record before January 1, 1981, or on lots in partitions or subdivisions that have received preliminary planning, zoning, and onsite wastewater treatment system approval before January 1, 1981, if one of the following can be met: (A) At the time the site is approved or the permit is issued, the lot complies with OAR 340-071-0100 through 340-071-0360 and 340-071-0410 through 340-071-0520. (B) The site meets all of the following conditions when a pressurized seepage bed is used: (i) Groundwater levels are not closer than 4 feet from the ground surface or closer than 3 feet from the bottom of the seepage bed. (ii) The seepage bed is constructed under OAR 340-071-0275(4) and (5). (iii) The seepage bed is sized on the basis of 200 square feet of bottom area per 150 gallons sewage flow. (iv) Design flows are limited to 375 gallons per lot, except for lots approved in a site evaluation for a larger flow. (v) All setbacks identified in Table 1 can be met, except that lots of record before May 1, 1973, must maintain a minimum 50-feet separation to public surface waters. (vi) Sufficient area exists on the lot to install a seepage bed and a replacement seepage bed, or the area reserved for replacement is waived pursuant to the exception in OAR 340-071-0150(4)(a)(C). (C) The site meets all of the following conditions when a bottomless sand filter is used. (i) Groundwater levels are not closer than 1 foot from the ground surface and not closer than 1 foot from the bottom of the sand filter. (ii) Design flows are limited to 375 gallons per day per lot, except for lots approved in a site evaluation for larger flows. (iii) The sand filter is sized at 1 square foot of bottom area for each gallon of sewage flow. (iv) The design and construction requirements in OAR 340-071-0295(3) and (4) must be met. A bottomless sand filter unit does not require a watertight floor, but does require watertight walls unless otherwise authorized by the agent. (v) All setbacks identified in Table 1 can be met, except that lots of record before May 1, 1973, must maintain a minimum 50 feet separation to public surface waters. (vi) Sufficient area exists on the lot to install an initial and replacement bottomless conventional sand filter, or the area for replacement is not required under OAR 340-071-0150(4)(a)(C). (b) An agent may approve a site or issue a construction-installation permit for a new onsite system within the area set forth in paragraph (c) of this section on lots created on or after January 1, 1981, if all rules in this division can be met. (c) The Alsea Dunal Aquifer is defined as all the land bounded on the East by Highway 101, on the west by the Pacific Ocean, and from Driftwood Beach Wayside South to the southern tip of the Alsea Bay Spit. (d) If groundwater monitoring in the Alsea Dunal Aquifer indicates unacceptable levels of degradation or if development of the aquifer as a source of drinking water is necessary or desirable, sewage collection and off-site treatment facilities must be installed unless further study demonstrates that such facilities are not necessary or effective to protect the beneficial use. (3) Christmas Valley Townsite, Lake County. (a) Within the area set forth in paragraph (b) of this section, the agent may consider the shallow groundwater table, if present, in the same manner as a temporary water table when issuing site evaluation reports and construction-installation permits. (b) The Christmas Valley Townsite is defined as all land within the Christmas Valley Townsite plat located within Sections 9, 10, 11, 14, 15 and 16 of Township 27 South, Range 17 East, Willamette Meridian, in Lake County. (4) Clatsop Plains Aquifer, Clatsop County. The Clatsop Plains Groundwater Protection Plan, prepared by R.W. Beck and Associates and adopted by Clatsop County, provides a basis for continued use of onsite wastewater treatment systems while protecting the quality of groundwater for future water supplies. For the plan to be successful, the following components must be accomplished. (a) By January 1, 1983, Clatsop County must identify and set aside aquifer reserve areas for future water supply development containing a minimum of 2-1/2 square miles. The reserve areas must be controlled so that the potential for groundwater contamination from nitrogen and other possible pollutants is kept to a minimum; (b) The agent may approve sites and issue construction permits for new onsite systems within the area generally known as the Clatsop Plains as described in paragraph (c) of this section if the conditions in paragraph (A) and paragraph (B), (C), or (D) of this subsection are met. (A) The lot or parcel was created in compliance with the appropriate comprehensive plan for Gearhart (adopted by County Ordinance 80-3), Seaside (adopted by County Ordinance 80-10), Warrenton (adopted by County Ordinance 82-15), or Clatsop County (adopted through Ordinance No. 79-10). (B) The lot or parcel does not violate any rule of this division. (C) The lot or parcel does not violate DEQ's Water Quality Management Plan or any rule in this division, except that the projected maximum sewage loading rate may exceed the ratio of 450 gallons per 1/2 acre per day. In this case, the onsite system must be either a sand filter system or a pressurized distribution system with a design flow not to exceed 450 gallons per day. (D) Use of standard onsite systems to serve single-family dwellings within planned developments or clustered-lot subdivisions complies with the following requirements: (i) The planned development or clustered-lot subdivision is not located within Gearhart, Seaside, Warrenton, or their urban growth boundaries. (ii) The lots do not violate any rule of this division, except the projected maximum sewage loading rate may exceed the ratio of 450 gallons per acre per day. (iii) DEQ is provided satisfactory evidence through a detailed groundwater study that the use of standard systems will not constitute a greater threat to groundwater quality than would occur with the use of sand filter systems or pressurized distribution systems. (c) The area generally known as Clatsop Plains is bounded by the Columbia River to the North; the Pacific Ocean to the west; the Necanicum River, Neawanna Creek, and County Road 157 on the south; and the Carnahan Ditch-Skipanon River and the foothills of the Coast Range to the east. (5) Within areas east of the Cascade Range where the annual precipitation does not exceed 20 inches, the agent may issue a construction-installation permit authorizing installation of a standard system to serve a single - family dwelling if the requirements in paragraphs (a) and (b) of this section are met. (a) Minimum site criteria. (A) The parcel or lot is 10 acres or larger. (B) The slope gradient does not exceed 30 percent. (C) The soils are diggable with a backhoe to a depth of at least 24 inches. (D) The site complies with the provisions of OAR 340-071-0220(1)(b), (f), (g), (h), (i), (j), and (k). (b) Minimum construction requirements. (A) The system must contain at least 225 linear feet of absorption trench for design flows not exceeding 450 gallons per day. Larger design flows must be sized on the basis of 75 linear feet per each 150 gallons of sewage flow. (B) The system must be constructed and backfilled as OAR 340-071-0220(3), (4), (5), (7), (8), (9), (10), (11), and (12) require. (c) The owner or owner's authorized representative may submit a single application to the agent for both a site evaluation report and a construction-installation permit. Such application must be submitted under OAR 340-071-0160 or 340-071-0162 and include the applicable evaluation and permit fees in OAR 340-071-0140. (d) The agent may waive the pre-cover inspection for a system installed pursuant to this section if the system installer submits the following information to the agent at the time construction of the system is complete: (A) A detailed, accurate as-built plan of the constructed system; (B) A list of all material used in the construction of the system; and (C) A written certification on a DEQ-approved form that the construction complies with the permit and rules in this division and OAR chapter 340, division 73. (e) The Agent may waive the site evaluation for a single-family dwelling if the requirements in this subsection are met. These conditions are set forth in an addendum to the memorandum of agreement (contract) between the County and DEQ. (A) Minimum site criteria. (i) The lot or parcel is 80 acres or larger. (ii) The separation distance between the proposed onsite system and the nearest dwelling not served by the proposed system is at least 1/4 mile. (iii) The nearest property line to the proposed system is at least 100 feet; the nearest domestic water source is at least 200 feet; and the nearest public surface water is at least 200 feet. (iv) In the agent’s opinion, topographical and soils information submitted with the application, including but not limited to slope, terrain, landform, and rock outcrops, demonstrates that the property can be approved for an onsite system under this division. (B) Minimum construction requirements. (i) Sizing requirements of Tables 4 and 5 must be followed as closely as possible. In all cases the system must contain at least 225 linear feet of absorption trench for design flows not exceeding 450 gallons per day. Larger sewage flows must be sized on the basis of 75 linear feet per each 150 gallons of sewage flow. (ii) The system must be constructed and backfilled as closely as possible to the requirements in OAR 340-071-0220. The agent may waive watertight testing of tanks in the system. [ED. NOTE: All tables are found in OAR 340-071- 0800.] Statutory/Other Authority: ORS 183.335, 454.625, 468.020, 468B.010 & 468B.020 Statutes/Other Implemented: ORS 454.610 & 454.615 History: DEQ 29-2025, amend filed 10/01/2025, effective 01/01/2026 DEQ 47-2017, minor correction filed 12/14/2017, effective 12/14/2017 DEQ 15-2017, amend filed 10/31/2017, effective 11/01/2017 DEQ 14-2013, f. 12-20-13, cert. ef. 1-2-14 DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05 DEQ 4-1997, f. & cert. ef. 3-7-97 DEQ 20-1996(Temp), f. & cert. ef. 10-14-96 DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95 DEQ 15-1986, f. & ef. 8-6-86 DEQ 8-1983, f. & ef. 5-25-83 DEQ 3-1983, f. & ef. 4-18-83 DEQ 20-1982, f. & ef. 10-19-82 DEQ 16-1982, f. & ef. 8-31-82 DEQ 2-1982, f. & ef. 1-28-82 DEQ 17-1981, f. & ef. 7-10-81 DEQ 10-1981, f. & ef. 3-20-81