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PDFWAC 173-160-291

What are the standards for the upper terminal of water wells?

(1) The watertight casing or curbing of any well shall extend at least six inches above the ground surface. Pit completion is prohibited.
(2) Where the site is subject to flooding, the top of the casing must be at least two feet above the estimated water level of a one hundred-year frequency flood.
(3) All drilled wells shall be capped to prevent contamination of the aquifer. The cap shall be designed for that purpose and consist of metal or plastic material that is mechanically secured or welded to the casing. All wells shall be equipped with an access port that allows for the measurement of the depth to water surface, or with a pressure gage that indicates the shut-in pressure of a flowing artesian well. See Figure 6. The access ports and pressure gages or other openings in the cover are sealed or capped to prevent entrance of surface water or foreign material into the well.
(4) Any vent opening, observation ports or air-line equipment shall extend from the upper end of the well by watertight piping to a point at least six inches above land surface. The terminals of these facilities shall be shielded or sealed to prevent entrance of foreign matter or pollutants.
(5) A pitless adapter, or similar device is permitted on water wells if it is made with fittings approved by the department of health. The use and installation of pitless adapters must meet manufacturer's standards. The connection must be above static water level except for adapters specifically designed for installation below static water level.
(6) Any person who removes any part of a surface seal to install a pitless adapter shall be responsible to have the seal repaired by a licensed or otherwise qualified person so that the seal is brought up to land surface.
[Statutory Authority: Chapter 18.104 RCW. WSR 09-01-125 (Order 08-10), § 173-160-291, filed 12/19/08, effective 1/19/09; WSR 06-23-121 (Order 06-08), § 173-160-291, filed 11/21/06, effective 12/22/06; WSR 98-18-104 (Order 98-17), § 173-160-291, filed 9/2/98, effective 10/3/98. Statutory Authority: Chapter 18.104 RCW and RCW 43.21A.080. WSR 98-08-032 (Order 97-08), § 173-160-291, filed 3/23/98, effective 4/23/98.]
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