Sebastian Water Hardness & Quality Report (2026)

Sebastian, Florida, in Indian River County on the Indian River Lagoon south of Vero Beach — a waterfront community known for its recreational fishing and Sebastian Inlet State Park — receives its municipal water from the Sebastian City Utilities, drawing from the Upper Floridan Aquifer through production wells in Indian River County. The Floridan Aquifer is the principal drinking water source for virtually all of Indian River County, providing water to communities along Florida's Treasure Coast through a common deep carbonate aquifer system.

The moderately hard 135 mg/L hardness and TDS of 337.6 mg/L reflect the Upper Floridan Aquifer's characteristic carbonate signature in the Indian River County area. The Floridan Aquifer beneath this section of the Atlantic coastal ridge is composed primarily of the Eocene Avon Park Formation — an ancient dolomite formed from the alteration of shallow-water marine limestones under warm burial conditions — and the overlying Ocala Group limestone. Water circulating through these Eocene carbonate formations for millennia naturally dissolves calcium and magnesium bicarbonate, producing a moderately hard supply that is characteristic of Florida's East Coast Atlantic Floridan zone.

At 135 mg/L, Sebastian's water is moderately hard — familiar and manageable for East Coast Florida living. Scale builds gradually in kettles and appliances over months, the dishwasher benefits from rinse aid, and shower glass needs periodic acidic cleaning to stay clear. Quarterly descaling of heating appliances is the standard schedule. The PFAS level of 6.8 ppt warrants a certified drinking water filter — Indian River County has some PFAS contributions from the Treasure Coast's military and aviation presence and the broader Floridan Aquifer recharge zone's industrial inputs.