Proton MRS thermometry exploits the property of temperature dependence of water signal. Most of MRS thermometry utilizes partially suppressed water signal or separately measured water signal without water suppression, in addition to the water suppressed signal for metabolites. This work shows that these approaches are either inaccurate or imprecise. The resultant errors may undermine clinically significant temperature changes. Simultaneous or interleaved measurement of unsuppressed water signal and metabolite/lipid signal is desirable.