Lutherville-Timonium Water Hardness & Quality Report (2026)

Lutherville-Timonium, Maryland, in Baltimore County — an unincorporated Baltimore County community adjacent to Towson and Cockeysville in the north Baltimore suburbs — receives its municipal water from Baltimore City Water, drawing from Loch Raven Reservoir (Gunpowder River, Baltimore County) through the Baltimore City water treatment plant.

The moderately hard 132.5 mg/L hardness and TDS of 268.8 mg/L reflect the north Baltimore Loch Raven watershed's moderate Piedmont calcareous character — somewhat harder than the DC Potomac communities due to the Gunpowder Falls-Loch Raven watershed's mixed Piedmont metamorphic input. The Loch Raven Reservoir (Gunpowder Falls) drains the Maryland Piedmont — Precambrian Glenarm Group Gneiss (moderately insoluble), Cambrian Setters Formation (calcareous — moderate hardness contributor), and Cambrian Cockeysville Marble (calcareous limestone — the primary hardness source at north Baltimore). The Cockeysville Marble calcareous input elevates the north Baltimore supply hardness above the Potomac-fed communities.

At 132.5 mg/L, Lutherville-Timonium'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 7.1 ppt warrants a certified drinking water filter — Aberdeen Proving Ground (Harford County — AFFF, directly in the Gunpowder Falls watershed above Loch Raven) and the Baltimore metro PFAS complex contribute to Lutherville-Timonium's elevated readings.