A Guide To Municipal Water: Supply, Treatment, And More

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Municipal water supplies the public and businesses with clean water. While the water quality of municipal water is usually safe to drink, municipal water goes through treatment to ensure it follows the EPA’s guidelines for potable water and removes contaminants that may cause adverse health conditions. The five stages of municipal water treatment are chemical addition, coagulation and flocculation, sedimentation and clarification, filtration, and disinfection. 

Municipal water is another term used for tap water. In many countries, municipal water is supplied to industries and the public via underground pipe systems. Although municipal water does not have the same water quality properties as purified and filtered water, most municipal water sources meet the quality of drinking water standards. 

However, despite municipal water having the opportunity to meet drinking water standards, less than 1% is consumed in the United States. Municipal water is mainly used for cleaning, cooking, and watering plants and crops.

As municipal water is occasionally used for drinking and other human uses, monitoring water quality is essential, even if municipal water is not consumed, there will be times when it comes into contact with the public. 

Understanding the water quality of municipal water will determine how often and when you can use it. 

What Is Municipal Water?

Municipal water systems are public waterway systems to provide users with tap water. These systems include municipal water plants and water storage facilities such as water tanks. The main sources of municipal water include large wells, lakes, rivers, or reservoirs.

Before municipal water is sent to storage facilities, the water is treated and processed to remove most of the impurities before use. However, it is important to note that even though municipal water must meet the water quality standards set out by the Environmental Protection Agency (EPA), water quality varies from community to community. 

The EPA standards state that potable water must remove nearly 90 contaminants, yet some communities continue to treat water to remove 99% of all contaminants to ensure people have access to very clean and healthy drinking water. Alternatively, some communities will only meet the minimum EPA requirements, so there is a noticeable difference between how the municipal water tastes and the water quality. 

Overall, municipal is generally safe to drink, but water quality should be tested to prevent the risk of developing certain health conditions and diseases from water contaminants.

Can You Drink Municipal Water?

As mentioned, municipal water is typically healthy to drink. For municipal water to be considered safe, the water must be treated and tested to meet the EPA standards. If after testing, the municipal water doesn’t meet the EPA standards, the water must be treated again to remove water contaminants. 

What Are The EPA Drinking Water Standards?

The EPA states that drinking water must remove over 90 contaminants to legally be classified as safe for human consumption.

The maximum contaminant level (MCL) and maximum contaminant level (MCLG) for drinking water standards are as followed:

  • Nitrite (measured as nitrogen): 1 mg l−1
  • Nitrate: 10 mg l−1
  • pH: 6.5 – 8.5

To be 100% confident in municipal water’s water quality, you must test it yourself. 

What Contaminants Affect The Water Quality Of Municipal Water?

Many contaminants affect the water quality of municipal water. These include various manufacturing processes, pesticides and fertilizers, natural minerals and chemicals, wastewater releases, and sewer overflows. 

Health Conditions Linked To Poor Water Quality

If municipal water contains too many contaminants and is consumed as drinking water, there is a higher risk of developing the following health conditions. 

  • Cardiovascular & reproductive issues
  • Neurological disorders
  • Gastrointestinal problems

People at higher risk of water-borne illnesses, diseases, and disorders are:

  • The elderly 
  • Pregnant women
  • Young children, particularly infants
  • People that are immune compromised

Treating municipal water is relatively simple, yet extremely important. If water is not treated in communities, people could become seriously sick.

Municipal Water Treatment

There are many processes to treat municipal water. The process used depends on how contaminated the water is, but they all have the same end goal – to make sure that the water quality meets the EPA standard. 

Municipal water treatment involves five key steps:

  1. Chemical Addition
  2. Coagulation & Flocculation
  3. Sedimentation & Clarification
  4. Filtration 
  5. Disinfection 

Chemical Addition

Chemicals that react with the alkalinity of water to form an insolvable participate, are added to the municipal water. The chemicals added are called coagulants, as they stick suspended particles in the water together, forming gelatinous particles called flocculation. Flocculation (floc) is the compaction of small particles into larger particles. 

Many chemicals can treat municipal water, but aluminum sulfate is most commonly used. Other chemicals such as ferrous sulfate, ferric chloride, sodium aluminate, and polymers (manufactured chemicals) can also be used. 

Whichever chemical/coagulant is added to the water, they must all be mixed thoroughly to form a heavy floc. 

Coagulation & Flocculation

During coagulation and flocculation, positively charged chemicals are put into the water to neutralize the charges in a treatment unit called the flocculator. The dissolved particles placed into the water bind with the chemicals, to form floc, like in the previous step. 

Sedimentation & Clarification

Next, the water is transferred to the sedimentation basin or clarifier. During this process, the large particle floc settles to the ground of the clarifier, which is then scraped to the center of the basin using a rake. 

Once settled, the settled sludge is removed from the clarifier. It is then sent to a sedimentation or disposal pond. It is here where specialized pumps are used to remove the suspended material. This is critical to avoid weighing down the filters, allowing a greater amount of water to be filtered. 


The clarified water (from the previous step) flows into the filters, so it can be collected in the drainage system in the filter unit. 

Filters are typically made up of sand or gravel, but more recently, activated carbon is the preferred media choice. Activated carbon eliminates organic compounds associated with poor odor and taste, and acts as mechanical filtration of particulate matter, improving the quality of water. 


Once the water has been filtered, it may appear clean and clear, but there could be bacteria and viruses still in the water, so to eradicate these, the water must go through a disinfection process. 

The most common disinfection treatment is the use of chlorine, also known as chlorination. Chlorine (such as chlorine dioxide and chlorine gas) is added to the water and monitored so that the water is sterilized without affecting the taste and odor of the delivered water. 

What Filtration Systems Are Used For Municipal Water Treatment?

The filtration system used to treat municipal water depends on the purity required for use. There are two main types of filtration that you should know about when treating municipal water – particle filtration and membrane filtration. 

Particle Filtration

Particle filtration systems use physical or mechanical techniques to separate dissolved solids from fluids. The three main filter types are as followed.

1. Cartridge Filtration

These trap particles using folded material or another means of a filter screen. Surface filters remove particles located on the liquid’s surface. Depth filters utilize dense media to attract the remaining particles.

2. Bag Filtration

For smaller water treatment systems, bag filtration is used to catch solid particles from the water. The bag contains pores, which vary in size depending on what the water system needs to remove. For systems where there is a high flow rate, multi-bag filtration can be installed.

3. Self-Cleaning Filters

These are slightly different from the particle filtration methods above, as they are self-cleaning. For continuous water systems, these types of filters are ideal to remove debris in mechanical processes or backwashing systems.

Membrane Filtration

If particle filtration fails to provide clean and healthy municipal water, the water goes through membrane filtration. These filtration systems are used when the best water quality is needed. The three most accepted types of membrane filtration are:

  • Microfiltration: Microfiltration does not require pressure. The filter pore size membrane ranges from 0.1 to 1 Micron. 
  • Reverse Osmosis: To remove tiny organic particles. This is the greatest level of the filtration process. 
  • Ultrafiltration: This is performed under low water flow and pressure. The water is then driven through pores between 5 and 100 nanometers. Chemicals may also be added during ultrafiltration to add ultra-clean the water. 

Microfiltration and ultrafiltration are typically used before RO water treatment. 

Municipal Water Treatment Applications

Municipal water is not only treated for human use, many industries and applications require treated water. The main applications that rely on municipal water include drinking water supplies and household use (bathing, cooking, cleaning, etc.).

Types Of Water Treatment Sensors

Here at Atlas Scientific, we have a wide range of water treatment sensors to test the quality of water. The main sensors available for water treatment include:

You can browse our full range of water treatment probes here

Summing Up, Municipal Water

Whether you are worried about your household’s water quality, or you work in the water treatment industry, municipal water treatment is key for safe water resources. 

If municipal water contains too many contaminants, it can cause many issues such as poor odor and taste, and in worse cases, adverse health conditions for consumers. When treating municipal water, chemical addition, flocculation, coagulation, sedimentation and clarification, filtration, and finally disinfection are completed. 

At Atlas Scientific, we can provide you with all the water testing sensors you need to monitor water quality. If you have any questions regarding testing municipal water do not hesitate to contact the world-class team at Atlas Scientific

Water Treatment Sensors

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