Abstract: An emergency tempered water blending apparatus is described which has a threeway, thermostatic mixing valve for mixing a cold water intake stream with a hot water intake stream at effective proportions to form a tempered water output stream having a desired, preset temperature. When the flow of the cold water is detected, a normally-closed valve in the tempered water stream opens allowing flow to the user. Water flow defaults to cold water upon either a mechanical or electrical failure, or upon the temperature of the tempered water becoming too hot to reduce probability of failure in hot mode.