In earlier works, characterization and stress corrosion cracking of casings of brine recirculation pumps, used in desalination plants, had been investigated. These casings which were manufactured from two types of Ni resist ductile irons have been reported to show different service lives. Material selection of casings is believed to be one of possible factors to extend the service life of these pumps. Two types of stainless steels; UNS S31603 and UNS S32750 have been recommended as substitutes to Ni resist ductile irons. In this work, mechanical, metallurgical, and electrochemical tests have been conducted on as received samples, made of these two types of stainless steels. Results have shown considerable higher yield and tensile strengths and corrosion resistance for the UNS S32750 over the UNS S31603. Results have also shown reproduced pitting behavior illustrated by measured pitting potentials and visual observations for UNS S31603 samples. UNS S32750 samples have shown no signs of pitting.