Provides continuous waterline treatment for safe and compliant dental-unit waterline quality. This 2-cartridge system effectively treats lines for up to 1 year or up to 240 liters. Safe for patient contact, nontoxic, and noncorrosive. Controls microbial contamination by eluting nonallergenic and elemental iodinated resin. Includes a 6-month automatic replacement indicator for a convenient reminder and a “dummy straw” for easy shocking. Not for use with municipal lines.