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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.

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

Holiday Closure Notice:

OWP will be closed on Monday, July 4, 2022, in observance of the 4th of July holiday.

Water and Wastewater Terms Beginning O

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

ORP (pronounce as separate letters)

See oxidation-reduction potential (ORP).