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On-Site Water and Wastewater

On-site Glossary  

Abandoned well - a well whose use has been permanently discontinued and has not been properly decommissioned.

Absorption area - that area in a subsurface disposal field used to absorb treated effluent.

Absorption bed - a shallow excavation, usually rectangular, wider than five feet, containing gravel and perforated distribution pipes, that receives septic tank effluent and allows it to seep into the surrounding porous soil.

Alternative system - a particular design or type of on-site wastewater disposal system or component of a system based upon improvements or development in technology of sewage disposal.

Approved tank manufacturer - a firm manufacturing tanks approved by the department and holding a valid water and wastewater equipment manufacturer certificate issued by the department.

Aquifer - a formation, group of formations or part of a formation, that contains sufficient saturated permeable material to yield water to wells and springs.

Aquifer--Unconfined - a zone of water saturation where atmospheric pressure is freely communicated to the zone. It's upper limit is at atmospheric pressure and it has no upper confining layer.

Aquifer--Confined - a formation in which the groundwater is isolated from the atmosphere, by impermeable geologic formations. Confined groundwater is generally subject to pressure greater than atmospheric and rises to a level above the upper limit of its aquifer when allowed.

Artesian well - a well in which the water from the confined source aquifer rises above the upper limit of the aquifer.

AWWTS- Advanced Wastewater Treatment System

Bentonite - a swelling principally aluminum silicate clay.

Certified groundwater professional - a groundwater professional certified by a nationally recognized organization.

Casing - the pipe made of approved material installed in a well bore hole to prevent sidewall caving, to provide access to an aquifer, and to provide protection from up-hole or surface contamination of the aquifer.

Certificate of On-Site Systems Approval - a written confirmation signed by an engineer and the department certifying that the on-site sewer or water system serving a single-family dwelling is adequate and complies with all applicable state and local regulations and codes.

Certified pump installer - a person or firm holding a valid state contractor's license, business license, and a current pump installer's certificate issued by the department.

Cesspool - a subsurface pit which receives untreated wastewater.  Cesspools are not allowed in the MOA

Contaminant - any substance which, if introduced into a potable water source, would render the water unsafe for human or animal consumption.

Deep absorption trench - a 12- to 36-inch-wide ditch which contains at least four feet of gravel below the horizontal perforated distribution pipe. It receives treated effluent and allows the effluent to seep into the surrounding porous soil.

Disinfection - a chemical or physical process utilized to eliminate pathogenic organisms from a potable water source, equipment or storage facility.

Drawdown - the distance between the static water level and the pumping water level in a well or an aquifer.

Drive shoe - a forged or tempered steel collar with a cutting edge, attached to the lower end of a casing, to protect the bottom end of the casing as it is driven or otherwise forced into the bored hole.

Earth privy - a device for the disposal of human excreta in a pit in the earth.

Flowing artesian well - a water well in which the water from the confined source aquifer flows naturally to the ground surface without benefit of mechanical lift equipment.

Granules - a dry grouting material approved by the department.

Gravel - rock measuring 0.5 to 2.5 inches in diameter with no more than three percent of the material passing a number 200 sieve screen (0.074 millimeter diameter openings).

Groundwater - subsurface water permanently or seasonally occupying a zone of saturation.

Grout - any stable material, in a slurry or granular form impervious to and capable of preventing the vertical movement or migration of water.

Hazardous substance - those substances which because of quantity, concentration, or physical/chemical/infectious characteristics may pose a threat to human health or to the environment when improperly treated, handled, stored and transported, and disposed of. Hazardous substances include those defined as hazardous under federal, state and municipal laws.

Holding tank - a watertight covered receptacle designed and built to receive and store domestic wastewater for disposal at another location.

Hydrogeologist - a certified professional geologist, licensed by the state who practices groundwater science or a certified groundwater professional.

Impermeable barrier - material with a percolation rate greater than 120 minutes per inch.

Insulation - high-density direct burial polystyrene insulation or other material of comparable insulating value approved by the department.

Licensed well driller - a person holding a valid state contractor's business license and a current well driller's certificate issued by the department.

Lift station - a tank or chamber accompanied by a pump and related controls used to retain effluent and periodically discharge it.

Mound system - a soil absorption system that is elevated above the natural soil surface utilizing suitable fill material, horizontal perforated distribution pipes, and standpipes.

On-site wastewater disposal system - any wastewater storage, treatment, or disposal system which serves a facility located on a lot which is not connected to a public sewer.

Outer annular space - the void space between the side wall of the drilled bore hole of a well and the outside casing wall.

Permit - a written document issued by the department permitting the construction and/or development of a subsurface potable water source or waste water disposal systems.

Percolation rate - the rate at which water flows or trickles through porous soils, as determined by a percolation test.

Percolation test - a falling-head percolation test as described on page 41 of the U.S. Environmental Protection Agency's design manual entitled, "On-Site Wastewater Treatment and Disposal Systems," 1980 edition, and taken at the depth of a proposed absorption system or similar component of an on-site wastewater disposal system. The test determines the rate at which water is absorbed in the soil.

Pitless adapter - a device attached to the well casing below ground level, constructed so as to permit the flow of water from the well casing.

Protective well radius - a prescribed horizontal distance between the well head and potential source of contaminants.

Pump Install Log - a written report showing the property owner, location, and all pertinent information and data relative to the installation of the well pump.

Pumper (Certified) - a person holding a permit issued by the department to pump & transport on-site wastewater disposal tank effluent.

Recovery - the ability of the water in a well to return to its static level after being drawn down during a period of pumping.

Sanitary well seal - a mechanical seal installed on the top of the well casing to prevent water or contaminants from entering the well.

Seepage pit - a covered porous walled pit through which treated effluent may seep into surrounding porous soil.

Septic tank - the water tight receptacle designed to receive domestic wastewater and allow the clarified liquids to be discharged into a subsurface soil absorption system.

Shallow absorption trench - a trench five feet or less in width which contains not less than six inches and not more than four feet of gravel below the horizontal distribution pipe.

Static water level - the water level in a well that has not been affected by withdrawal of groundwater.

Stick up - that portion of a well's casing that extends above the surface of the ground.

Subsurface disposal field - an absorption bed, deep or shallow absorption trench, seepage pit or mound system that distributes septic effluent for percolation into the natural soils.

Subsurface drain - any subsurface drainage structure which intercepts or diverts underground water flows.

Surface water - any persistent natural or man-made source of water, which is not directly attributable to a single rainfall or snowmelt event. Surface waters include all lakes, ponds, streams, springs, intermittent or seasonal flows, natural and artificial bodies of water and all of the water of the State of Alaska as defined in AS 5.25.100(5) as amended.

Vault privy - an earth privy in which the pit is lined with an impervious material and in which provision is made for the removal of excreta.

Wastewater - water containing human excreta, food waste, wash water and other wastes commonly discharged into a water-carried sewage disposal system, and such diluting water as may have entered the waste disposal system. Wastewater does not mean liquids containing hazardous wastes as defined by federal, state or municipal law.

Water table - surface of a body of unconfined groundwater at which the pressure is equal to that of the atmosphere.

Water well - a bored, drilled, driven or dug excavation utilized for the purpose of extracting groundwater from an aquifer.

Watershed - the area which has been zoned under municipal regulations.

Well cap - a mechanical cover installed on the top of a well casing which may or may not be water tight.

Well decommissioning - the process or procedure by which production from a well has been discontinued and the well removed from service.

Well drilling contractor - a licensed well driller as defined above.

Well log - a written report showing the property owner, location, and all pertinent information and data relative to the drilling and completion of the well.

Well pit - an excavation, opening, shaft or hole surrounding a well.

Well test - a test that is conducted by a licensed well driller, a licensed pump installer, a hydrogeologist, or an engineer to determine the sustained production capability of the well.

Well yield - the sustained production rate of a well determined by a well test.

    • On-Site Water and Wastewater
    • Acting Building Official : Ross Noffsinger
    • 4700 Elmore Road, Anchorage, AK 99507
    • 907 343-7904