West Monroe Water Hardness & Quality Report (2026)

West Monroe, Louisiana, in Ouachita Parish — a Ouachita Parish city adjacent to Monroe and Ruston on the Ouachita River in north-central Louisiana — receives its water from the West Monroe Water system, drawing from the Ouachita River (Ouachita Parish) through the north-central Louisiana distribution.

The moderately hard 100 mg/L hardness and TDS of 207.9 mg/L reflect the north-central Louisiana Ouachita Parish supply's moderate calcareous character — the Ouachita River drains the Ouachita Mountains' Mississippian shales and Cretaceous calcareous formations, producing moderate hardness typical of the Louisiana-Arkansas Ouachita corridor communities (compare Crowley LA: 166 mg/L on the harder south Louisiana coastal supply). The Ouachita River at Ouachita Parish — Cretaceous Nacatoch Formation (calcareous — primary hardness contributor), Mississippian Stanley Shale (insoluble — dilutant from upper watershed), and Quaternary Ouachita alluvium (calcareous — TDS contributor).

At 100 mg/L, West Monroe's water is moderately hard — scale builds in kettles and appliances over months, dishwashers benefit from rinse aid, and faucet aerators need periodic cleaning. Quarterly descaling is appropriate. The PFAS level of 9.6 ppt warrants a certified drinking water filter — the Ouachita Parish north-central Louisiana industrial and petrochemical corridor contribute to West Monroe's elevated PFAS readings.