340-071-0100 Definitions As used in OAR 340, divisions 71 and 73, unless otherwise specified: (1) "Absorption Area" means the entire area used for underground dispersion of the liquid portion of sewage including the area designated for a future replacement system. It may consist of a seepage pit, absorption field, or combination of the two. It may also consist of a cesspool, seepage bed, bottomless sand filter, or evapotranspiration-absorption system. (2) "Absorption Facility" means a system of open-jointed or perforated piping, alternative distribution units, or other seepage systems for receiving the flow from septic tanks or other treatment facilities that are designed to distribute effluent for oxidation and absorption by the soil within the zone of aeration. (3) "Absorption Field" means a system of absorption trenches, a seepage trench, or a system of seepage trenches. (4) "Absorption Trench" means a ditch or a trench installed into soil, permeable saprolite, or diggable bedrock, with vertical sides and a substantially flat bottom. (5) “Accessory dwelling unit”, ADU, means an interior, attached or detached residential structure that is used in connection with or that is accessory to a single-family dwelling, and is located on the same lot or parcel as the single-family dwelling. It contains provisions for cooking, eating, sleeping and sanitation, as defined by state or local building code, and does not exceed two bedrooms and size limitations established by state or local land use regulations. (6) "Active Sand Dune" means wind-drifted ridges and intervening valleys, pockets, and swales of sand adjacent to the beach. The sand is grayish-brown with little or no horizon, color, or textural difference. Active dunes are either bare of vegetation or lack sufficient vegetation to prevent blowing of sand. (7) "Aerobic Sewage Treatment Facility" means a sewage treatment plant that incorporates a means of introducing air and oxygen into the sewage to provide aerobic biochemical stabilization during a detention period. Aerobic sewage treatment facilities may include anaerobic processes as part of the treatment system. (8) "Aerobic System" means an alternative system that incorporates a septic tank or other treatment facility, an aerobic sewage treatment facility, and an absorption facility to provide treatment before dispersal. (9) "Agent" means the director or person authorized to act on the Director’s behalf, frequently referring to DEQ or contract county staff performing onsite permitting activities. (10) "Alteration" means expansion or change in location of an existing system or any part of it. Major alteration is the expansion or change in location of the soil absorption facility, treatment unit, or any part of it. Minor alteration is the replacement or relocation of a septic tank or other components of the system other than the soil absorption facility, or a change in distribution technique or method. (11) "Alternative System" means any onsite wastewater treatment system DEQ or the Commission approves for use in lieu of the standard subsurface system. (12) "Alternative Treatment Technologies" means an alternative system that incorporates aerobic and other treatment technologies or units not specifically described elsewhere in this division. (13) "Approved Material" means construction items that DEQ approved for use. (14) "Approved Criteria" means methods of design or construction that DEQ approved for use. (15) "ASTM" means American Society of Testing Materials. (16) "Authorization Notice" means a written document issued by an agent establishing that an existing onsite wastewater treatment system appears adequate for its intended use. (17) "Authorized Representative" means a person with written authorization to act as another person's delegate. (18) "Bedroom" means any room within a dwelling accepted as a bedroom by state or local building departments. (19) "Biochemical Oxygen Demand" (BOD5) means the quantity of oxygen used in the biochemical oxidation of organic matter in five days at 20 degrees centigrade under specified conditions and reported as milligrams per liter (mg/L). (20) "Black Waste" means human body wastes including feces, urine, other substances of body origin, and toilet paper. (21) "Capping Fill System" means an alternative system that incorporates an absorption trench with an effective sidewall installed a minimum of 12 inches into the natural soil below a soil cap of specified depth and texture. (22) "Carbonaceous Biochemical Oxygen Demand" (CBOD5) means BOD minus the nitrogenous oxygen demand, typically measured in mg/L. (23) "Cesspool" means a lined pit that receives raw sewage, allows separation of solids and liquids, retains the solids, and allows liquids to seep into the surrounding soil through perforations in the lining. (24) "Chemical Recirculating Toilet Facility" means a toilet facility in which black wastes are deposited and carried from a bowl by a combination of chemically treated and filtered liquid waste and water. (25) "Chemical Toilet Facility" means a nonflushing, nonrecirculating toilet facility in which black wastes are deposited directly into a chamber containing a solution of water and chemical. (26) "Clayey Soil" means mineral soil with over 40 percent clay that shrinks and develops wide cracks when dry and swells and shears when wet, forming slickensides and wedge-shaped structure. Clayey soil is very hard or extremely hard when dry, very firm when moist, and very sticky and very plastic when wet. (27) "Claypan" means a dense, compact clay layer in the subsoil. It has a much lower permeability than the overlying soil horizon from which it is separated by an abrupt boundary. Claypans are hard when dry and very sticky and very plastic when wet and impede movement of water, air, and growth of plant roots. (28) "Combustion Toilet Facility" means a toilet facility wherein black wastes are deposited directly into a combination chamber for incineration. (29) "Commercial Facility" means any structure or building or portion of one other than a single-family dwelling or single-family dwelling with an accessory dwelling unit. (30) "Commission" means the Environmental Quality Commission. (31) "Community System" means an onsite system that serves more than one lot or parcel, more than one condominium unit, or more than one unit of a planned unit development. (32) "Completed Application" means an application form that is completed in full, is signed by the owner or owner's authorized representative or, for WPCF permits, by the applicant or applicant's authorized representative, and is accompanied by all required exhibits and fees. (33) "Conditions Associated with Saturation" means soil morphological properties that may indicate the presence of a water table that persists long enough to impair system function and create a potential health hazard. These conditions include depleted matrix chromas caused by saturation and not a relict or parent material feature, and the following: (a) High chroma matrix with iron depletions. Soil horizons whose matrix chroma is 3 or more in which there are some visible iron depletions having a value 4 or more and a chroma of 2 or less. Iron-manganese concentrations as soft masses or pore linings may be present but are not diagnostic of conditions associated with saturation. (b) Depleted matrix with iron concentrations. Soil horizons whose matrix color has a value of 4 or more and a chroma of 2 or less as a result of removal of iron and manganese oxides. Some visible zones of iron concentration are present as soft masses or pore linings. (c) Depleted matrix without iron concentrations. Soil horizons whose color is more or less uniform with a value of 4 or more and a chroma of 2 or less as a result of removing iron and manganese oxides. These horizons lack visible iron concentrations as soft masses or pore linings. (d) Reduced matrix. Soil horizons whose color has a value of 4 or more and a chroma of 2 or less with hues that are often, but not exclusively, on the gley pages of the Munsell Color Book. On exposure to air, yellow colors form within 24 hours as some of the ferrous iron oxidizes. (e) Dark colored soils with organic matter accumulation. Mineral soils with a high amount of decomposed organic matter in the saturated zone, a value of 3 or less, and a chroma of 1 or less. Included in this category are organic soils with a minor amount of mineral matter. (f) Soils with a dark surface. The upper surface layer has a dark color with a value of 3 or less and a chroma of 1 or less immediately underlain by a layer with a chroma of 2 or less. (g) Iron stripping and staining in sandy soils. Soil horizons in which iron/manganese oxides or organic matter or both have been stripped from the matrix, exposing the primary base color of soil materials. The stripped areas and trans-located oxides or organic matter form a diffuse splotchy pattern of two or more colors. (h) Salt-affected soils. Soils in arid and semi-arid areas that have visible accumulations of soluble salts at or near the ground surface. (i) Dark colored shrink-swell soils. Vertisols whose colors have values of 3 or less and chromas of 1 or less. Iron concentrations may be present but are not diagnostic of conditions associated with saturation. (j) Other soils that lack the diagnostic value and chroma as described in this section but remain saturated long enough to impair system function and have a high water table under OAR 340-071-0130(22). (34) "Confining Layer" means a layer associated with an aquifer that, because of low permeability, does not allow water to move through it perceptibly under head differences occurring in the groundwater system. (35) "Construction" includes installing a new system, or a part of one, or altering, repairing, or extending an existing system. The grading, excavating, and earth-moving work connected with installing, altering, or repairing a system or a part of one is considered system construction. (36) "Contract County" means a local unit of government that has entered into an agreement with DEQ under OAR 340-071-0120 to perform duties of DEQ under this division. (37) "Conventional Sand Filter" means a filter with 2 feet or more of sand filter media designed to chemically and biologically process septic tank or other treatment unit effluent from a pressure distribution system operated on an intermittent basis. (38) "Curtain Drain" means a groundwater interceptor that is designed to divert groundwater from an absorption facility. The drain creates a "curtain" to block water from reaching the absorption facility. (39) "Cut-manmade" means a land surface resulting from mechanical land shaping operations where the modified slope is greater than 50 percent and the depth of cut exceeds 30 inches. (40) "DEQ" means the Department of Environmental Quality. (41) "Design Capacity" means the design flow a system is designed to treat and disperse. (42) "Design Criteria" means the criteria used in designing onsite wastewater treatment systems including but not limited to dimensions, geometry, type of materials, size of drain media or filter media, absorption field sizing, depth, grade or slope, hydraulic loading rate, or any other factor relevant to the successful operation of the system. It does not include absorption area siting criteria. (43) “Design flow” means the maximum daily quantity of sewage for which a system is sized and designed. The design flow allows for a safety margin and reserve capacity for the system during heavy use. (44) "Designer" means a person who plans onsite wastewater treatment and dispersal technology for an onsite system. (45) "Director" means the Director of the Department of Environmental Quality. (46) "Disposal Trench" means "absorption trench." (47) "Distribution Box" means a watertight structure that receives septic tank or other treatment facility effluent and distributes it concurrently into 2 or more header pipes leading to the absorption area. (48) "Distribution Pipe" means an open-jointed or perforated pipe used in the dispersion of septic tank or other treatment facility effluent into absorption trenches, seepage trenches, or seepage beds. (49) "Distribution Unit" means a distribution box, dosing tank, diversion valve or box, header pipe, or other means of transmitting septic tank or other treatment unit effluent from the effluent sewer to the distribution pipes. (50) "Diversion Valve" means a watertight structure that receives septic tank or other treatment facility effluent through one inlet and distributes it to 2 outlets, only one of which is used at a time. (51) "Dosing Tank" means a watertight receptacle placed after a septic tank or other treatment facility equipped with a pump. (52) "Dosing Septic Tank" means a unitized device performing functions of both a septic tank and a dosing tank. (53) "Drainfield" means an "absorption field." (54) "Drain Media" means clean washed gravel or clean, crushed rock with a minimum size of 3/4 inch and a maximum size of 2-1/2 inches used in the distribution of effluent. The material must be durable and inert so that it will maintain its integrity, will not collapse or disintegrate with time, and will not be detrimental to the performance of the system. Drain media also includes any product or material approved by DEQ for distribution of effluent in an absorption field. (55) "Dwelling" means any structure or building or portion thereof that is used, intended, or designed to be occupied for human living purposes including but not limited to houses, houseboats, boathouses, mobile homes, recreational cabins, travel trailers, hotels, motels, and apartments. (56) "Effective Seepage Area" means the sidewall area within an absorption trench or a seepage trench from the bottom of the trench to a level 2 inches above the distribution pipes, the sidewall area of any cesspool, seepage pit, unsealed earth pit privy, graywater waste absorption sump seepage chamber, or trench with drain media substitute, or the bottom area of a pressurized soil absorption facility installed in soil. (57) "Effective Soil Depth" means the depth of soil material above a layer that impedes movement of water and air and growth of plant roots. Layers that differ from overlying soil material enough to limit effective soil depth are hardpans, claypans, fragipans, compacted soil, bedrock, saprolite, and clayey soil. (58) "Effluent Filter" means an effluent treatment device installed on the outlet of a septic tank or outside the septic tank in a separate enclosure and designed to prevent the passage of suspended matter larger than 1/8 inch in size. (59) "Effluent Lift Pump" means a pump used to lift septic tank or other treatment facility effluent to a higher elevation. (60) "Effluent Sewer" means that part of the system of drainage piping that conveys partially treated sewage from a septic tank or other treatment facility into a distribution unit or an absorption facility. (61) "Emergency Repair" means immediate action to repair a failing system when sewage is backing up into a dwelling or building or to repair a broken pressure sewer pipe. It does not include the construction of new or additional absorption facilities but does include using the septic tank as a temporary holding tank until new or additional absorption facilities can be permitted and constructed. (62) "Equal Distribution" means the distribution of effluent to a set of absorption trenches in which each trench receives effluent in equivalent or proportional volumes. (63) "Escarpment" means any naturally occurring slope greater than 50 percent that extends vertically 6 feet or more from toe to top, is characterized by a long cliff or steep slope that separates two or more comparatively level or gently sloping surfaces, and may intercept one or more layers that limit effective soil depth. (64) "Existing Onsite Wastewater Treatment System" means any installed onsite wastewater treatment system constructed in conformance with the rules, laws, and local ordinances in effect at the time of construction. (65) "Existing System" means "existing onsite wastewater treatment system." (66) "Failing System" means any system that discharges untreated or incompletely treated sewage or septic tank effluent directly or indirectly onto the ground surface or into public waters or that creates a public health hazard. (67) "Family Member" means any one of two or more persons related by blood or by law. (68) "Fecal Coliform" means bacteria common to the digestive systems of warm-blooded animals and cultured in standard tests. The term is typically used to indicate fecal pollution and the possible presence of enteric pathogens and is measured as colonies/100ml. (69) "Filter Fabric" means a woven or spun-bonded sheet material used to impede or prevent the movement of sand, silt, and clay into drain media. (70) "Fragipan" means a loamy subsurface horizon with high bulk density relative to the horizon above, seemingly cemented when dry, and weakly to moderately brittle when moist. Fragipans are mottled and low in organic matter, and they impede movement of water and air and growth of plant roots. (71) "Governmental Unit" means the state or any county, municipality, or political subdivision or any agency thereof. (72) "Grade" means the rate of fall or drop in inches per foot or the percentage of fall of a pipe. (73) "Graywater" means household sewage other than "black wastes," such as bath water, kitchen waste water, and laundry wastes. (74) "Graywater Waste Sump" means a receptacle or series of receptacles designed to receive hand-carried graywater for dispersal into the soil. (75) "Grease and Oils" means a component of sewage typically originating from food stuffs, consisting of compounds of alcohol or glycerol with fatty acids. (76) "Groundwater Interceptor" means any natural or artificial groundwater or surface water drainage system, including drain tile, curtain drain, foundation drain, cut banks, and ditches, that intercept and divert groundwater or surface water from the area of the absorption facility. (77) "Hardpan" means a hardened layer in soil caused by cementation of soil particles with silica, calcium carbonate, magnesium carbonate, iron, or organic matter. The hardness does not change appreciably with changes in moisture content. Hardpans impede movement of water and air and growth of plant roots. (78) "Header Pipe" means a tight-jointed part of the sewage drainage conduit that receives septic tank effluent from the distribution box, drop box, or effluent sewer and conveys it to the absorption area. (79) "Headwall" means a steep slope at the head or upper end of a land slump block or unstable landform. (80) "Holding Tank" means a watertight receptacle designed to receive and store sewage to facilitate treatment at another location. (81) "Holding Tank System" means an alternative system consisting of the combination of a holding tank, service riser, and level indicator (alarm), designed to receive and store sewage for intermittent removal for treatment at another location. (82) "Hydrosplitter" or "hydrasplitter" means a hydraulic device to proportion flow under pressure by the use of one or more orifices. (83) "Incinerator Toilet Facility" means "combustion toilet facility." (84) "Individual System" means a system that is not a community system. (85) "Individual Water Supply" means a source of water and a distribution system that provides water for drinking, culinary, or household uses and is not a public water supply system. (86) "Industrial Waste" means any liquid, gaseous, radioactive, or solid waste or a combination thereof resulting from any process of industry, manufacturing, trade, or business or from developing or recovering any natural resources. (87) "Intermittent Sand Filter" means a conventional sand filter. (88) "Intermittent Stream" means any public surface water or groundwater interceptor that continuously flows water for a period greater than two months in any one year but not continuously for that year. (89) "Invert" is the lowest portion of the internal cross section of a pipe or fitting. (90) "Large System" means any onsite system with a design flow greater than 2,500 gallons. (91) "Lateral Pipe" means "distribution pipe." (92) "Maintenance" means taking the actions necessary to keep onsite system components properly functioning as designed. Maintenance is further defined as: (a) Major Maintenance means repairing or replacing a broken distribution or drop box or a broken or plugged effluent sewer pipe where: (A) The box or pipe meets the requirements in this division and construction standards in division 073; and (B) A certified maintenance provider with a sewage disposal service license or certified installer with a sewage disposal license performs the work. (b) Minor Maintenance includes, but is not limited to, repairing or replacing of a tank riser or lid, or pump, screen, filter, or other component internal to the tank that: (A) Is the same make and model; or (B) Meets the requirements in this division. (93) "Maintenance provider" means a person who performs maintenance of onsite systems and: (a) Possesses adequate skills and knowledge regarding onsite wastewater treatment, absorption facilities, and system functions to competently inspect and maintain onsite systems, and (b) Is certified under OAR 340-071- 0650. (94) “Municipality” means a city, county, county service district, special service district, sanitary authority or sanitary district. (95) "Mechanical Sewage Treatment Facility" or "Mechanical Oxidation Sewage Treatment Facility" means an aerobic sewage treatment facility. (96) "Nonwater-Carried Waste Facility" means any toilet facility that has no direct water connection, including but not limited to pit privies, vault privies, and portable toilets. (97) "Occupant" means any person living or sleeping in a dwelling. (98) "Onsite Sewage Disposal System" means "onsite wastewater treatment system." (99) "Onsite Wastewater Treatment System" means any existing or proposed subsurface onsite wastewater treatment and dispersal system including but not limited to a standard subsurface, alternative, experimental, or nonwater-carried sewage system. It does not include systems that are designed to treat and dispose of industrial waste as defined in OAR chapter 340, division 045. (100) "Operating Permit" means a WPCF permit issued under these rules. (101) "Owner" means any person who alone, jointly, or severally: ( a ) Has legal title to any single lot, dwelling, dwelling unit, or commercial facility; ( b ) Has care, charge, or control of any real property as agent, executor, administrator, trustee, commercial lessee, or guardian of the estate of the holder of legal title; or ( c ) Is the contract purchaser of real property. (102) "Peer Review" means a review by at least three members of a scientific community recognized as experts in the field of study and well-rehearsed with scientific principles and experimentation. (103) "Permanent Groundwater Table" means the upper surface of a saturated zone that exists year-round. The thickness of the saturated zone and resulting elevation of the permanent groundwater table may fluctuate as much as 20 feet or more annually, but the saturated zone and associated permanent groundwater table is present at some depth beneath land surface throughout the year. (104) "Permit" means the written document, issued and signed by an agent, that authorizes a permittee to install a system or any part of one and, in some cases, to operate and maintain the system under the permit. (105) "Permit Action" means an agent’s issuing, modifying, renewing, reinstating, or revoking a permit. (106) "Person" includes individuals, corporations, associations, firms, partnerships, joint stock companies, public and municipal corporations, political subdivisions, the state and any of its agencies, and the federal government and any of its agencies. (107) "Pollution" or "Water Pollution" means any alteration of the physical, chemical, or biological properties of any waters of the state, including change in temperature, taste, color, turbidity, silt, or odor of the waters, or any discharge of any liquid, gaseous, solid, radioactive, or other substance into any waters of the state that, alone, or in connection with any other substance, threatens to create a public nuisance or render such waters harmful, detrimental, or injurious to public health, safety, or welfare or to domestic, commercial, industrial, agricultural, recreational or other legitimate beneficial uses or to livestock, wildlife, fish, or other aquatic life or their habitat. (108) "Portable Toilet" means any self-contained chemical toilet facility that is housed within a portable toilet shelter and includes but is not limited to construction-type chemical toilets. (109) "Portable Toilet Shelter" means any readily relocatable structure built to house a toilet facility. (110) "Pressure Distribution Lateral" means piping and fittings in pressure distribution systems that distribute septic tank or other treatment unit effluent to drain media through small diameter orifices. (111) "Pressure Distribution Manifold" means piping and fittings in a pressure distribution system that supply effluent from pressure transport piping to pressure distribution laterals. (112) "Pressure Distribution System" means any system designed to uniformly distribute septic tank or other treatment unit effluent under pressure in an absorption facility or treatment unit. (113) "Pressure Transport Piping" means piping that conveys sewage effluent from a septic tank or other treatment or distribution unit typically by means of a pump. (114) "Pretreatment" means the wastewater treatment that takes place prior to discharging to any component of an onsite wastewater treatment system, including but not limited to pH adjustment, oil and grease removal, BOD5 and TSS reduction, screening, and detoxification. (115) "Prior Approval" means a written approval for an onsite wastewater treatment system for a specific lot issued before January 1, 1974. (116) "Prior Construction Permit" means a subsurface wastewater treatment system construction- installation permit issued before January 1, 1974, by a county that had an ordinance requiring construction-installation permits for subsurface wastewater treatment systems. (117) "Privy" means a structure used for disposal of human waste without the aid of water. It consists of a shelter built above a pit or vault in the ground into which human waste falls. (118) "Projected Daily Sewage Flow" means the anticipated peak daily quantity of sewage an establishment produces. (119) "Public Health Hazard" means the presence of sufficient types or amounts of biological, chemical, physical, or radiological agents relating to water or sewage that cause, or threaten to cause, human illness, disorders, or disability. These include but are not limited to pathogenic viruses, bacteria, parasites, toxic chemicals, and radioactive isotopes. (120) "Public Waters" means lakes, bays, ponds, impounding reservoirs, springs, wells, rivers, streams, creeks, estuaries, marshes, inlets, canals, the Pacific Ocean within the territorial limits of the State of Oregon, and all other bodies of surface or underground waters, natural or artificial, inland or coastal, fresh or salt, public or private, except private waters that do not combine or effect a junction with natural surface or underground waters, that are wholly or partially within or bordering the state or within its jurisdiction. (121) "Recirculating Gravel Filter (RGF)" means a gravel filter wastewater treatment system in which a portion of the filtered effluent is mixed with septic tank effluent in a recirculation/dilution tank and redistributed to the filter. (122) "Recirculating Gravel Filter System" means a recirculating gravel filter and an absorption facility used to treat wastewater. (123) "Redundant Absorption Field System" means a system in which two complete absorption fields are installed, the absorption trenches of each system alternate with each other, and only one system operates at a given time. (124) "Repair" means installing all portions of a system necessary to eliminate a public health hazard or pollution of public waters a failing system creates. (a) Major repair is replacing the soil absorption facility, treatment unit, or any part of it. (b) Minor repair is replacing a septic tank, broken pipe, distribution unit, or any part of the onsite system external to the septic tank or treatment facility except the soil absorption system. Unless classified as a major repair or major maintenance, any replacement of a part of a system with a part that does not meet the original design specifications is a minor repair. (125) "Residential Strength Wastewater" means septic tank effluent that does not typically exceed five-day biochemical oxygen demand (BOD5) of 300 mg/L; total suspended solids (TSS) of 150 mg/L; total Kjeldahl nitrogen (TKN) of 150 mg/L; oil & grease of 25 mg/L; or concentrations or quantities of other contaminants normally found in residential sewage. (126) "Sand Filter Media" means a medium sand or other approved material used in a conventional sand filter. The media must be durable and inert so that it will maintain its integrity, will not collapse or disintegrate with time, and will not be detrimental to the system’s performance. The particle size distribution of the media must be determined through a sieve analysis conducted under ASTM C-117 and ASTM C-136. The media must comply with the following particle size distribution: 100 percent passing the 3/8 inch sieve, 95 percent to 100 percent passing the No. 4 sieve, 80 percent to 100 percent passing the No. 8 sieve, 45 percent to 85 percent passing the No. 16 sieve, 15 percent to 60 percent passing the No. 30 sieve, 3 percent to 15 percent passing the No. 50 sieve, and 4 percent or less passing the No. 100 sieve. (127) "Sand Filter Surface Area" means the area of the level plane section in the medium sand horizon of a conventional sand filter located 2 feet below the bottom of the drain media containing the pressurized distribution piping. (128) "Sand Filter System" means an alternative system that combines a septic tank or other treatment unit; a dosing system with effluent pump and controls, piping and fittings; a sand filter; and an absorption facility to treat wastewater. (129) "Sanitary Drainage System" means that part of a system's drainage piping that conveys untreated sewage from a building or structure to a septic tank or other treatment facility, to a service lateral at a curb or in a street or alley, or to another disposal terminal holding human or domestic sewage. The sanitary drainage system consists of a building drain or building drain and building sewer. (130) "Saprolite" means weathered material underlying the soil that grades from soft thoroughly decomposed rock to rock that has been weathered sufficiently so that it can be broken in the hands or cut with a knife. It has rock structure instead of soil structure and does not include hard bedrock or hard fractured bedrock. (131) "Saturated Zone" means a three-dimensional layer, lens, or other section of the subsurface in which all open spaces including joints, fractures, interstitial voids, and pores are filled with groundwater. The thickness and extent of a saturated zone may vary seasonally or periodically in response to changes in the rate or amount of groundwater recharge or discharge. (132) "Scum" means a mass of sewage solids floating at the surface of sewage that is buoyed up by entrained gas, grease, or other substances. (133) "Seepage Area" means "effective seepage area." (134) "Seepage Bed" means an absorption system having absorption trenches wider than 3 feet. (135) "Seepage Pit" means a cesspool that has a treatment facility such as a septic tank ahead of it. (136) "Seepage Trench System" means a system with absorption trenches with more than 6 inches of drain media below the distribution pipe. (137) "Self-Contained Nonwater-Carried Waste Containment Facility" means a system in which all waste is contained in a watertight receptacle, including but not limited to vault privies, chemical toilets, combustion toilets, recirculating toilets, and portable toilets. (138) "Septage" means the domestic liquid and solid sewage pumped from septic tanks, cesspools, holding tanks, vault toilets, chemical toilets or other similar domestic sewage treatment components or systems and other sewage sludge not derived at sewage treatment plants. (139) "Septic Tank" means a watertight receptacle that receives sewage from a sanitary drainage system and is designed to separate solids from liquids, digest organic matter during a period of detention, and allow the liquids to discharge to a second treatment unit or to a soil absorption facility. (140) "Septic Tank Effluent" means partially treated sewage that is discharged from a septic tank. (141) "Serial Distribution" means the distribution of effluent to a set of absorption trenches constructed at different elevations in which one trench at a time receives effluent in consecutive order beginning with the uppermost trench by means of a drop box, a serial overflow, or another approved distribution unit. The effluent in an individual trench must reach a level of 2 inches above the distribution pipe before effluent is distributed to the next lower trench. (142) "Sewage" means water-carried human and animal wastes, including kitchen, bath, and laundry wastes from residences, buildings, industrial establishments, or other places, together with any groundwater infiltration, surface waters, or industrial waste that may be present. (143) "Sewage Disposal Service" means: (a) Constructing onsite wastewater treatment systems, including placing portable toilets, or any part of one; (b) Pumping out or cleaning onsite wastewater treatment systems, including portable toilets, or any part of one; (c) Disposing of material derived from pumping out or cleaning onsite wastewater treatment systems. including portable toilets; or (d) Grading, excavating, and earth-moving work connected with the operations described in paragraph (a) of this section. (144) "Sewage Stabilization Pond" means a pond designed to receive the raw sewage flow from a dwelling or other building and retain that flow for treatment without discharge. (145) "Site Evaluation Report" means a report on the evaluation of a site to determine its suitability for an onsite system prepared under OAR 340-071-0150. (146) "Slope" means the rate of fall or drop in feet per 100 feet of the ground surface. It is expressed as percent of grade. (147) "Soil Permeability" refers to the ability of a soil to transmit water or air. (148) "Soil Separate" means the size of soil particles described in Table 7. (149) "Soil Texture" means the amount of each soil separate in a soil mixture. Field methods for judging the texture of a soil consist of forming a cast of soil, both dry and moist, in the hand and pressing a ball of moist soil between thumb and finger. (a) The major textural classifications are defined as follows and shown in Table 6: (A) Sand: Individual grains can be seen and felt readily. Squeezed in the hand when dry, this soil will fall apart when the pressure is released. Squeezed when moist, it will form a cast that will hold its shape when the pressure is released but will crumble when touched. (B) Loamy Sand: Consists primarily of sand, but has enough silt and clay to make it somewhat cohesive. The individual sand grains can readily be seen and felt. Squeezed when dry, the soil will form a cast that will readily fall apart, but if squeezed when moist, a cast can be formed that will withstand careful handling without breaking. (C) Sandy Loam: Consists largely of sand, but has enough silt and clay present to give it a small amount of stability. Individual sand grains can be readily seen and felt. Squeezed in the hand when dry, this soil will readily fall apart when the pressure is released. Squeezed when moist, it forms a cast that will not only hold its shape when the pressure is released but will withstand careful handling without breaking. The stability of the moist cast differentiates this soil from sand. (D) Loam: Consists of an even mixture of the different sizes of sand and of silt and clay. It is easily crumbled when dry and has a slightly gritty, yet fairly smooth feel. It is slightly plastic. Squeezed in the hand when dry, it will form a cast that will withstand careful handling. The cast formed of moist soil can be handled freely without breaking. (E) Silt Loam: Consists of a moderate amount of fine grades of sand, a small amount of clay, and a large quantity of silt particles. Lumps in a dry, undisturbed state appear quite cloddy, but they can be pulverized readily; the soil then feels soft and floury. When wet, silt loam runs together in puddles. Either dry or moist, casts can be handled freely without breaking. When a ball of moist soil is passing between thumb and finger, it will not press out into a smooth, unbroken ribbon but will have a broken appearance. (F) Clay Loam: Consists of an even mixture of sand, silt, and clay that breaks into clods or lumps when dry. When a ball of moist soil is pressed between the thumb and finger, it will form a thin ribbon that will readily break, barely sustaining its own weight. The moist soil is plastic and will form a cast that will withstand considerable handling. (G) Silty Clay Loam: Consists of a moderate amount of clay, a large amount of silt, and a small amount of sand. It breaks into moderately hard clods or lumps when dry. When moist, a thin ribbon or 1/8-inch wire can be formed between thumb and finger that will sustain its weight and will withstand gentle movement. (H) Silty Clay: Consists of even amounts of silt and clay and very small amounts of sand. It breaks into hard clods or lumps when dry. When moist, a thin ribbon or 1/8 inch or smaller wire formed between thumb and finger will withstand considerable movement and deformation. (I) Clay: Consists of large amounts of clay and moderate to small amounts of sand and silt. It breaks into very hard clods or lumps when dry. When moist, a thin, long ribbon or 1/16-inch wire can be molded with ease. Fingerprints will show on the soil, and a dull to bright polish is made on the soil by a shovel. (b) Soil textural characteristics described in the United States Department of Agriculture Textural Classification Chart are incorporated here by reference. This textural classification chart is based on the Standard Pipette Analysis as defined in the United States Department of Agriculture, Soil Conservation Service Soil Survey Investigations Report No. 1 (See Table 6). [Table not included. See ED. NOTE.] (150) "Soil with Rapid or Very Rapid Permeability" means: (a) Soil that contains 35 percent or more of coarse fragments 2 millimeters in diameter or larger by volume with interstitial soil of sandy loam texture or coarser; (b) Coarse textured soil defined as loamy sand or sand in this rule; or (c) Stones, cobbles, gravel, and rock fragments with too little soil material to fill interstices larger than 1 millimeter in diameter. (151) "Split Waste Method" means a process where black waste sewage and graywater from the same dwelling or building are managed by separate systems. (152) "Stabilized Dune" means a sand dune that is similar to an active dune except that vegetative growth is dense enough to prevent blowing of sand. The surface horizon is either covered by a mat of decomposed and partially decomposed leaves, needles, roots, twigs, moss, or other vegetative material or contains roots to a depth of at least 6 inches and has a color value of 3 or less. (153) "Standard Subsurface System" means an onsite wastewater treatment system consisting of a septic tank, distribution unit, and absorption facility constructed under OAR 340-071-0220. (154) "Steep Slope System" means a seepage trench system installed on slopes greater than 30 percent and less than or equal to 45 percent. (155) "Subsurface Absorption System" means the combination of a septic tank or other treatment unit and an effluent sewer and absorption facility. (156) "Subsurface Sewage Disposal" means "subsurface wastewater treatment." (157) "Subsurface Disposal System" means "subsurface absorption system." (158) "Subsurface Wastewater Treatment" means dispersing wastewater from a septic tank or other treatment unit into the zone of aeration to be further treated through physical, chemical, or biological processes. (159) "System" or "onsite system" means "onsite wastewater treatment system." (160) "Temporary Groundwater Table" means the upper surface of a saturated zone that exists only on a seasonal or periodic basis. Like a permanent groundwater table, the elevation of a temporary groundwater table may fluctuate, but a temporary groundwater table and associated saturated zone will dry up for a period of time each year. (161) "Test Pit" means an open pit dug to sufficient size and depth to permit thoroughly examining the soil to evaluate its suitability for subsurface wastewater treatment. (162) "Third-Party" means a consulting firm, research institute, academic institute, or other similar entity with no vested interest in the outcome of test results of a material, design, or technology under evaluation. (163) "Tile Dewatering System" means an alternative system in which the absorption facility is encompassed with field collection drainage tile to reduce and control a groundwater table and create a zone of aeration below the bottom of the absorption facility. (164) "Time Dosing" means a method of pumping effluent where there is adequate effluent storage to manage surge flows within a time period, either daily or weekly, and meter the flow over the course of more than one day. This method requires adequate storage in a dosing tank or similar approved container, a control panel with a timer, and floats to activate timer and disable pump in periods of low flows. (165) "Toilet Facility" means a fixture housed within a toilet room or shelter to receive black waste. (166) "Total Kjeldahl Nitrogen" (TKN) means the combination of ammonia and organic nitrogen, excluding nitrate and nitrite nitrogen. (167) "Total Nitrogen" (TN) means the sum of all nitrogen forms. (168) "Total Suspended Solids" (TSS) means solids in wastewater that can be removed readily by standard filtering procedures in a laboratory and reported as milligrams per liter (mg/L). (169) "Treatment" means the alteration of the quality of wastewaters by physical, chemical, or biological means or combination thereof to reduce potential degradation of water quality or the environment and risk to public health. (170) "Treatment Standard 1" means a 30-day average of less than 20 mg/L of BOD5 and 20 mg/L of TSS. A 30-day average of less than 17 mg/L of CBOD5 is acceptable in lieu of the BOD5 value. (171) "Treatment Standard 2" means a 30-day average of less than 20 mg/L of BOD5 and 20 mg/L of TSS, a 30-day geometric mean of less than 400 fecal coliform per 100 milliliters, and a 30-day average of 30 mg/L of TN. A 30-day average of less than 17 mg/L of CBOD5 is acceptable in lieu of the BOD5 value. (172) "Turbidity" means the optical condition of waters caused by suspended or dissolved particles or colloids that scatter and absorb light rays instead of transmitting light in straight lines through the water column. Turbidity may be expressed as nephelometric turbidity units (NTU) measured with a calibrated turbidimeter. (173) "Underdrain Media" means the material placed under the sand filter media in a sand filter and consists of clean, washed pea gravel with 100 percent passing the 1/2 inch sieve, 18 to 100 percent passing the 1/4 inch sieve, 5 to 75 percent passing the No. 4 sieve, 24 percent or less passing the No. 10 sieve, 2 percent or less passing the No. 16 sieve, and 1 percent or less passing the No. 100 sieve. (174) "Unstable Landforms" means areas showing evidence of mass downslope movement such as debris flow, landslides, rockfall, and hummock hill slopes with undrained depressions upslope. Examples are landforms exhibiting slip surfaces roughly parallel to the hillside; landslide scars and curving debris ridges; fences, trees, and telephone poles that appear tilted; and tree trunks that bend uniformly as they enter the ground. Active sand dunes are unstable landforms. (175) "Vertisols" means a mineral soil characterized by a high content of swelling-type clays that in dry seasons cause the soils to develop deep, wide cracks. (176) "WPCF Permit" means a Water Pollution Control Facilities permit that has been issued under OAR chapter 340, divisions 045 or 071. (177) "Wastewater" means "sewage." (178) "Zone of Aeration" means the unsaturated zone that occurs below the ground surface and above the point at which the upper limit of the water table exists. [ED. NOTE: Tables referenced are not included in rule text. All tables are found in OAR 340- 071-0800.] Statutory/Other Authority: ORS 454.625 & 468.020 Statutes/Other Implemented: ORS 454.605 & 454.615 History: DEQ 29-2025, amend filed 10/01/2025, effective 01/01/2026 DEQ 66-2018, minor correction filed 04/05/2018, effective 04/05/2018 DEQ 39-2017, minor correction filed 12/14/2017, effective 12/14/2017 DEQ 15-2017, amend filed 10/31/2017, effective 11/01/2017 DEQ 11-2014, f. & cert. ef. 10-15-14 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 15-2000, f. & cert. ef. 10-11-00 DEQ 16-1999, f. & cert. ef. 12-29-99 DEQ 12-1997, f. & cert. ef. 6-19-97 DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95 DEQ 6-1988, f. & cert. ef. 3-17-88 DEQ 15-1986, f. & ef. 8-6-86 DEQ 8-1983, f. & ef. 5-25-83 DEQ 5-1982, f. & ef. 3-9-82 DEQ 10-1981, f. & ef. 3-20-81