Water and wastewater treatment plant and system operators typically do the following:

• Add chemicals, such as ammonia or chlorine, to disinfect water or other liquids
• Inspect equipment on a regular basis
• Monitor operating conditions, meters, and gauges
• Collect and test water and sewage samples
• Record meter and gauge readings and operational data
• Operate equipment to purify and clarify water or to process or dispose of sewage
• Clean and maintain equipment, tanks, filter beds, and other work areas
• Follow U.S. Environmental Protection Agency (EPA) regulations
• Ensure safety standards are met

It takes a lot of work to get water from natural sources - reservoirs, streams, and groundwater - into people's taps. Similarly, it is a complicated process to convert the wastewater from drains and sewers into a form that is safe to release into the environment.

The specific duties of plant operators depend on the type and size of the plant. In a small plant, one operator may be responsible for maintaining all of the systems. In large plants, multiple operators work the same shifts and are more specialized in their duties, often relying on computerized systems to help them monitor plant processes.

Water treatment plant and system operators work in water treatment plants. Fresh water is pumped from wells, rivers, streams, or reservoirs to water treatment plants, where it is treated and distributed to customers. Water treatment plant and system operators run the equipment, control the processes, and monitor the plants that treat water to make it safe to drink.

Wastewater treatment plant and system operators do similar work to remove pollutants from domestic and industrial waste. Used water, also known as wastewater, travels through sewer pipes to treatment plants where it is treated and either returned to streams, rivers, and oceans, or used for irrigation.