Moderately hard water: yes, SLS works. Very hard water: expect some loss of foam and detergency, and plan for it in the formula.

Calcium and magnesium ions interact with anionic surfactants and reduce their effective availability. In practice:

  • Detergent formulas handle this with builders and chelating agents (zeolites, citrates, carbonates) that bind the hardness ions — this is standard detergent chemistry, and SLS-based powders perform well in most markets.
  • In very hard water regions, or in formulas where you cannot load enough builders, SLS foam and cleaning drop noticeably.

The cleanest solution for hard-water markets is switching the primary surfactant to AOS (sodium C14-16 olefin sulfonate), which keeps its foam and detergency in mineral-rich water far better than sulfate esters. Many export detergents use an SLS/AOS blend to balance cost and hard-water robustness.

Tell us your target market’s water conditions and we will recommend a surfactant system — contact our technical team.