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Notice:

OWP continues to be short-staffed. Please place orders online rather than by phone to allow us to manage order volumes. We will do our best to process your orders and respond to your requests. We appreciate your patience and understanding.

As of July 1, 2022, OWP will only send paper test booklets and bubble sheets upon request and for a fee.

Water and Wastewater Terms Beginning H

A B C D E F G H I J K L M N O P Q R S T U V W Y Z

HTH (high test hypochlorite)

Calcium hypochlorite or Ca(OCl)₂.