Evaluation of the SCC growth rate response of ~12% Cr ferritic steels has been performed in high temperature water as a function of corrosion potential water purity stress intensity factor and other parameters. The range of alloys span from standard ~12% Cr ferritic steels to powder metallurgy alloys to ODS-nano-ferritic alloys to alloys irradiated up to 38 dpa. All alloys exhibit moderate susceptibility during SCC transitioning which employes cyclic loading but consistently show cessation of crack advance as the frequency or delta-K decreasees. Some alloys exhibit sustained growth at constant K but only at high stress intensity factors such as 40 MPa/m on 0.5T CT specimens.