OAR 690-210-0155: Additional Standards for Artesian Water Supply Wells

(1) Water supply wells penetrating into an artesian aquifer shall have an upper oversize drillhole at least four inches greater in diameter than the nominal diameter of the permanent well casing to be installed. Watertight unperforated casing shall extend and be sealed at least five feet into the confining interval immediately overlying the artesian water-bearing zone. In all cases, a minimum of 18 feet of casing and casing seal will be required. If cement grout is placed by a suitable method from the bottom of the casing (Methods A, B, or D, in Appendix 210-3 and Figure 210-1), the diameter of the upper oversize drillhole shall be at least two inches larger than the nominal diameter of the permanent well casing. (2) To complete the well, inner casing, liner, or a well screen may be installed. When artesian pressures are encountered in the absence of a confining interval, casing and casing seal requirements shall be determined by the Director upon written application. In the alternative, the person constructing the well may construct the well in conformance with the minimum standards for artesian wells with a confining interval, set forth in section (1) of this rule. (3) If an artesian water supply well flows at land surface, the well shall be equipped with a control valve and a watertight mechanical cap, threaded or welded, so that all flow of water from the well can be completely stopped. (4) All flowing artesian wells shall be equipped with a pressure gauge placed on a dead- end line. A petcock valve shall be placed between the gauge and well casing. (See Figure 210-7). (5) All flowing artesian water supply wells shall be tested for artesian shut-in pressure in pounds per square inch and rate of flow in cubic feet per second, or gallons per minute, under free discharge conditions. This data shall be reported on the well report. [ED. NOTE: To view attachments referenced in rule text, click here to view rule.]