how tap water is made

How is Tap Water Treated, Filtered & Delivered?

We are all used to getting our water by merely opening a tap. However, when you consider the origin of our water, many questions arise about the treatment our drinking water goes through before it reaches our homes. Our water comes from rivers, lakes and groundwater, where it gathers all kinds of contaminants that pose severe health risks to the consumers.

What are the typical contaminants of water?

Various microbes could contaminate surface water, and groundwater is typically considered safer. However, harmful chemicals in the environment or from human activities could contaminate groundwater. The following agents could also contaminate water:

  • Natural environmental minerals and chemicals such as fluorides, common salt and even arsenic
  • Contaminants that are not harmful but unacceptable because they influence the smell, taste, temperature or color of the water
  • Industrial wastes, fertilizers, pesticides and other harmful chemicals linked to human activities
  • Disease-causing pathogens, which are organisms like viruses, amoebas, bacteria, parasitic worms and their larvae and eggs

What are the typical water treatment processes?

Before leaving the treatment plants to storage tanks and then our homes, water undergoes the following purifying treatments:

  • Flocculation and coagulation: This process involves binding the dissolved particles and dirt into larger floc particles by adding specific chemicals to the water.
  • Sedimentation: The floc particles are heavy and sink to settle in the tank’s bottom.
  • Filtration: This part of the process allows the clear water to flow through filters including sand, gravel, and ultimately charcoal to filter out dissolved dust, chemicals, viruses, bacteria and parasites that escaped the previous two steps.
  • Disinfection: Finally, any remaining germs, viruses, bacteria and parasites are killed by adding chloramine or chlorine. At this time, fluorine is added for prevention of tooth decay.

What is the goal of the water treatment process?

The Environmental Protection Agency sets standards to be met by water treatment plants. There are more than 90 possible contaminants in water. The efficient application of water treatments must reduce contaminants and potential transmission risks for diseases to levels accepted by the EPA. Furthermore, drinking water must contain no pathogens known to endanger public health.

How can municipalities be sure no dangerous contaminants remain?

Municipalities have access to an extensive range of sensors to measure contaminants to ensure they are at safe levels, and the following sensors are even available to the public for testing their water:

  • Chlorine dioxide and chlorine sensor: This sensor measures the concentration of chlorine dioxide and chlorine in parts per million (ppm).
  • Oxidation reduction potential sensor: This sensor can indicate how effective the disinfection of the water is.
  • Ultraviolet transmittance sensor: With this sensor, the water’s organic content can be measured to know whether UV light intensity must be altered to improve disinfection.
  • pH sensor: The pH level indicates the acidity or alkalinity of the water. The desired pH level is the neutral measurement of 7, or as close to 7 as possible.

How is the water stored and transported?

After the filtration, purification and disinfection processes, the state of the water is called “potable,” and thousands of gallons flow into city reservoirs. A series of connected underground pipes distribute water across the city. The distribution pipes typically run between rows of buildings and houses after branching off from those running parallel to streets. Finally, a system called service lateral lines brings the water from the larger lines to each property’s mains to connect to the water system. The plumbing pipes take the water to all the water hookups from the meter connection, including faucets, bathtubs, showers, and toilets.

What role does gravity play in water distribution?

Most city water towers or reservoirs are built on hills or other elevated ground. That is ideal for taking advantage of gravity to move masses of water to cities for further distribution. However, water distributors use multiple pumps to get the water to every user when that is not possible. When this is the case, the consumers might have to pay a higher price to cover the extra costs of the power required to distribute the water.

What about other uses for water?

A significant percentage of treated water is distributed to homes, but local industrial plants, manufacturers and other businesses also receive their share. Overall, municipal water applications include drinking, cooking, bathing, cleaning, watering gardens, lawns and more. Some municipalities are geared to provide industries that use water for purposes unrelated to human consumption with non-potable water.

The Bottom Line

Every household in urban, suburban and rural populations must be able to use tap water without concerns about diseases and other adverse health conditions. Therefore, all municipal water goes through various processes and treatments to make it safe for human consumption.

Amanda Perkins

Amanda began her career as a technical writer for a healthcare group in 2008. Years after getting married and starting a family, she joined her husband Joshua on the Water Filter Authority journey to educate other families and households about safe, affordable, and effective water filtration systems.