A method of conditioning source water is comprised of: (a) acidifying source water by aluminum or iron chloride to prevent carboxylate from forming scale and emulsion and/or convert bicarbonate to carbon dioxide, and separating oil and/or carbon dioxide by hydrophobic membranes to produce a de-oiled and/or de-carbonated source water; (b) adding a hydrated lime or a hydrated lime with an amine solvent to separate magnesium hardness in the form of brucite and sulfate in the form calcium sulfoaluminate or calcium sulfoferrate to produce a de-brucited and de-sulfated source water; (c) if desired, reacting the excess amounts of the hydrated lime or the hydrated lime and amine solvent within the de-brucited and de-sulfated source water with carbon dioxide from step (a) to separate at least most of calcium hardness and produce a de-calcited source water; and (d) de-oxygenating the treated source water in step (b) or (c) by hydrophobic membranes.