Water Testing is a broad description for various procedures used to analyze water quality. Millions of water quality tests are carried out daily to fulfill regulatory requirements and to maintain safety.

Testing may be performed to evaluate:

• Ambient or environmental water quality – the ability of a surface water body to support aquatic life as an ecosystem. Environmental, Freshwater environmental quality parameters and Bioindicator.
• Wastewater – characteristics of polluted water (domestic sewage or industrial waste) before treatment or after treatment. Environmental and Wastewater quality indicators.
• "raw water" quality – characteristics of a water source prior to treatment for domestic consumption (drinking water). Bacteriological water analysis and specific tests such as turbidity and hard water.
• "Finished" water quality – water treated at a municipal water purification plant. Bacteriological water analysis and Category: Water quality indicators.
• Suitability of water for industrial uses such as laboratory, manufacturing or equipment cooling.