OAR 690-220-0050
Abandonment of Uncased Wells
(1)
Uncased portions of water supply wells to be permanently abandoned shall be completely filled with cement grout, concrete or unhydrated bentonite: (See Figure 220-1) (Figure 220-2)(2)
Uncased portions of water supply wells that penetrate a water-bearing formation may be abandoned with alternating layers of cement grout, concrete or unhydrated bentonite and clean gravel throughout the water-bearing zones in the following manner:(a)
In all cases, non water-bearing zones shall be filled with cement grout, concrete or unhydrated bentonite.(b)
Clean gravel may only be placed in the water-bearing zones verified by an original water supply well report or other documentation acceptable to the Department. A vertical column of gravel that exceeds a total length of 50 feet shall only be placed with prior Department approval. Non water-bearing portions shall be filled with a plug of cement grout, concrete or unhydrated bentonite. Gravel shall not exceed a maximum of 50% of well depth without prior Department approval. Gravel may be placed in multiple water-bearing zones, not to exceed 50 feet for each zone. In no case shall gravel be placed above 18 feet below land surface.
Source:
Rule 690-220-0050 — Abandonment of Uncased Wells, https://secure.sos.state.or.us/oard/view.action?ruleNumber=690-220-0050.