Jenks Water Hardness & Quality Report (2026)

Jenks, Oklahoma, in Tulsa County — a Tulsa suburb directly south of Tulsa on the Arkansas River, known as the Antique Capital of Oklahoma, a fast-growing Tulsa South suburb with strong retail and residential development along US-75 — receives its municipal water from the City of Jenks Water Department or the Tulsa Metropolitan Utility Authority (TMUA), which draws from Keystone Lake (Arkansas River impoundment west of Tulsa) or from the Spavinaw Reservoir system (the historic 1924 Tulsa water supply in Mayes County).

The very hard 256 mg/L hardness and high TDS of 561.1 mg/L reflect the Arkansas River-eastern Oklahoma watershed's Pennsylvanian carbonate cyclothem geology. The Arkansas River and Spavinaw Creek drain eastern Oklahoma's Pennsylvanian cyclothem terrain (the Morrow, Atoka, and McAlester formations — alternating marine limestone, shale, and coal of the Arkoma Basin), overlying Ordovician-Devonian carbonate formations (the Tulsa Formation and Viola Limestone). These Pennsylvanian marine limestones and the underlying Ordovician carbonate sequence produce the consistently hard water characteristic of eastern Oklahoma river supplies.

At 256 mg/L, Jenks's water is very hard — scale builds rapidly in kettles and appliances, dishwashers require rinse aid and softener salt, and showerheads and faucets develop heavy calcium encrustation. Monthly descaling of heating appliances is practical. A water softener is recommended for Jenks households. The PFAS level of 4.9 ppt warrants a certified drinking water filter — the Tulsa International Airport and the broader Tulsa metro industrial complex (petroleum refining, aerospace), and the Arkansas River corridor's industrial legacy contribute to Jenks's PFAS background.