Senate Bill 1962, also known as House Bill 1983, amends Tennessee Code Annotated, Title 68, Chapter 221, Part 7, to establish new maximum hardwater level standards for public water systems. The bill defines "hardwater" as water containing dissolved minerals expressed as calcium carbonate equivalents and sets the maximum allowable hardwater level at 180 milligrams per liter (mg/L). Public water systems that receive state funds for system upgrades after July 1, 2026, must comply with this standard upon completion of the upgrade. Those that do not receive such funds are grandfathered in and are not required to comply unless they receive state funding for upgrades.

Additionally, the bill includes provisions for a seasonal runoff exemption, allowing public water systems to temporarily exceed the hardwater standard if they can demonstrate that the increase is due to seasonal runoff. To qualify for this exemption, systems must notify the department, provide documentation, and submit a remediation plan if required. The bill also mandates monitoring and reporting of hardwater levels, with results included in annual water quality reports. The enforcement of these provisions will be carried out by the department in accordance with existing enforcement mechanisms. The act is set to take effect on July 1, 2026.