Why would a town add sodium hydroxide to its water supply?
If your water system is one that does water softening, than the sodium Hydroxide (also called caustic soda or lye) would be used to raise the PH before going into a softening tank. With a higher PH the mineral in the water will stick to something like sand that is added to the tank. The sand will get heaver and can be dropped out. Sodium hydroxide is also used in making soft drinks, chocolate and other foods.
