What Is Potable Water?

Potable water, also called drinking water, is used for drinking, showering, hand washing, cooking and other sanitary needs. Water produced in the United States is deemed potable if it meets certain environmental standards. If the water supply is from a public system, as opposed to a private well, these standards are set by the U.S. Environmental Protection Agency (EPA), under Title 40 CFR, Part 141.

The EPA, authorized under the Safe Drinking Water Act (SWDA), sets nationwide uniform drinking water quality standards for all states, and is responsible for ensuring that state and local environmental agencies test drinking water regularly. Those agencies test for levels of bacteria, nitrates, inorganic and organic chemicals, radioactive elements, lead and copper. The 1986 amendments to the SDWA authorize the EPA to set maximum levels of contaminants allowable in drinking water.


What Is Potable Water?
Potable water, also called drinking water, is used for drinking, showering, hand washing, cooking and other sanitary needs. Water produced in the United States is deemed potable if it meets certain environmental standards. If the water supply is from a public system, as opposed to a private well, these standards are set by the U.S. Environmental Protection Agency (EPA), under Title 40 CFR, Part 141.

The EPA, authorized under the Safe Drinking Water Act (SWDA), sets nationwide uniform drinking water quality standards for all states, and is responsible for ensuring that state and local environmental agencies test drinking water regularly. Those agencies test for levels of bacteria, nitrates, inorganic and organic chemicals, radioactive elements, lead and copper. The 1986 amendments to the SDWA authorize the EPA to set maximum levels of contaminants allowable in drinking water.
What Makes Water Not Potable?

Water is deemed non-potable if it exceeds potable water standards. These standards establish thresholds for levels of bacteria, nitrates, inorganic and organic chemicals, radioactive elements, lead and copper, disinfectants, and numerous other pollutants. They also include tests for turbidity, that is, the cloudiness of the water, and pH.


Examples of pollutants and their thresholds include:

  • Chloride (250 ppm)
  • Fluoride (1.4 to 2.4 mg/L)
  • Sulfate (250 ppm)
  • Lead (0.05 mg/L)
  • Fecal Coliforms 1/100 ml (Proposed: 0/100 ml)
  • Arsenic 0.05 mg/L
  • Chromium Hexavalent (0.05 mg/L)
  • Cadmium (0.010 mg/L)
  • Mercury (0.002 mg/L)
What Is The Water treatment Process for Potable Water?

Potable water is produced by taking raw source water, such as that drawn from lakes, rivers, reservoirs and other surface bodies of water, and subjecting them to filtration and contact with disinfectant agents. Potable water treatment plants include some or all of the following steps, depending on the source of the water and its quality:


  • Clarification: Typically, the clarification step begins with two complementary processes: Coagulation and flocculation. During coagulation, iron or aluminum salts, such as aluminum sulphate, ferric sulphate, ferric chloride or polymers, are added to the water. These chemicals have a positive charge and neutralize the negative charge of dissolved and suspended particles in the water. The particles bind together, or coagulate, and larger particles, or floc, are settle to the bottom of the water tank. This binding process is often called flocculation.


  • In some cases, a process known as dissolved air flotation (DAF) is used. In DAF, microbubbles adhere to the solids and float them to the top of the floatation zone. Clarified water is collected from the laterals at the bottom of the DAF. Sludge is then either hydraulically removed over a stationary weir by raising the water level on a set interval, or mechanically removed with a scraper.


  • Filtration: Different types of filters can be used to produce potable water. The type of filter varies on the specifics of the application and the quality of the source water. These include reverse osmosis, nanofiltration, ultrafiltration, microfiltration.


  • Disinfection: Chlorine remains one of the most widespread methods of water disinfection. Other methods include ozone and ultraviolet, two well recognized methods for water and wastewater disinfection in the industrial and municipal markets. Each can be used for the inactivation of viruses. In addition to disinfection, ozone is also an effective treatment for taste, odor and color removal, iron and manganese reduction, as well as being a flocculating agent.
How Is Industrial Waste Water Treated To Make It Potable?

While industrial wastewater can be treated extensively, it generally is not used to create potable water. More typically industrial wastewater is treated to a level where it can be safely discharged into the environment, which serves as a buffer. Before it is discharged, industrial wastewater is often subject to an industrial pretreatment program (IPP) tailored to a specific industry, such as oil and gas processing, and food and beverage production.


In addition to the IPP, industrial wastewater treatment typically follows these basic steps:


  • Step 1: screening, first to remove large items and second grit.
  • Step 2: primary clarification to separate solid organic matter.
  • Step 3: aeration to encourage conversion of NH3 to NO3 and provide oxygen for bacteria to grow.
  • Step 4: secondary clarification to allow remaining organic sediment to settle, often through chemical treatment.
  • Step 5: disinfection using chlorination, UV, or other methods.
  • Step 6: discharge of the water; and disposal of solids; reclamation of biosolids/biogas.
How SUEZ Can Help With Potable Water Standards and Distribution Systems
SUEZ strives every day to ensure safe, clean water is readily available for the communities we serve and for generations to come. We offer multi-layered municipal water treatment processes to supply the highest quality of water possible in sufficient quantities, and to gather and treat wastewater so that it meets or surpasses the strictest government standards before it can be returned to the environment. Our sophisticated monitoring technology allows us to closely monitor rainfall every day to make sure reservoirs are at optimal capacity, and, if necessary, we establish conservation precautions.

SUEZ designs water treatment systems ranging from traditional to highly sophisticated, and we offer local authorities technical solutions to meet their municipal size and sanitary quality requirements. SUEZ specializes in various treatment techniques including settling, flotation, UV, activated carbon and filtration. We also offer solutions to eliminate micropollutants and to reduce water hardness through collective carbonate removal.

Contact a representative to learn more about water treatment and distribution solutions offered by SUEZ North America.