The principal water‐bearing units (in descending stratigraphie order) in Pipeline Canyon are the alluvium, the Dilco Coal Member of the Crevasse Canyon Formation, the Torrivio Sandstone Member of the Gallup Formation, and the Upper and Lower Gallup Sandstones. Presently, the alluvium is recharged by a perennial, southward‐flowing stream sustained by mine dewatering discharge in addition to natural precipitation and runoff. Localized infiltration has created ground‐water mounds in the alluvium. Artesian conditions may exist in sandstone units which are adjacent and hydraulically connected to the alluvium in these areas. Basement faults have produced the Fort Wingate and Pipeline Canyon lineaments which intersect in the area of investigation. Fault‐related fracturing of the sandstones allows for significant ground‐water recharge via the overlying alluvium. Flow in the sedimentary formations is generally to the northeast, while the alluvial system flows to the southwest. The natural water quality for the aquifers in the area is dominated by sodium and sulfate ions. However, complete characterization of the natural water quality is complex because of ground‐water contamination by acidic tailings fluids from a local uranium mill.