Cation exchange resin based on polystyrene sunfonated to form R-SO3Na (cationid S108) for water softening was investigated. The results show that total exchange capacity of ion exchange resin Lewatit Mono S108 for Ca2+, Mg2+ according to isothermal model Langmuir was 239.09 mg/g and 185.19 mg/g respectively. The examination of cation exchange capacity on the column has carried out, total capacity ion exchange of exchange resin Lewatit Mono S108 on the column for Ca2+, Mg2+ from aquous solution and total hardness from hard water was 176 mg/g, 172 mg/g and 169 mg/g respectively. The column exhausted resin can be regenerated by sea salt solution and the operating capacity of an ion exchange resin was ~ 97 mg/g.