Behind the Main: The Key Parts of Your Municipal Water System
If your house gets its water from a well and has a septic tank, then it’s easy to see how your water system works. However, the majority of people get their water from a city or municipal water system, and there’s a lot that goes on before the water gets to your water main and after it goes out your drains.
This could be a reservoir, or an underground aquifer. The water has to come from somewhere, and most systems are set up to pull it from a source that doubles as storage to make sure they have enough during a dry spell. The water from the source can travel into the system a number of different ways, including underground pipes, covered tunnels, or open-air aqueducts.
If you’ve ever gone swimming in a reservoir or hiking near a river, you probably have a good idea why you shouldn’t drink the water without filtering or purifying it first. In addition to the microscopic threats such as bacteria and viruses, there’s plenty of much more obvious problems, like suspended dirt, plant matter, and substances like gasoline from boats.
To make sure the water is drinkable, it goes through three stages. Clarification removes the large items, filtration removes the smaller particles, and disinfection kills bacteria and viruses.
If you want the water to go anywhere, it’s got to have some force to get it through the pipes, and that force is pressure. Pumps and compressed air apply that pressure directly, and several of these pumping stations will be scattered through the distribution system. For systems that only use pumps or compressed air, treated water is usually stored at the treatment plant.
Water towers combine storage and pressurization in a single location. The tank of the tower provides storage for treated water until it’s need. The weight of all that water pushes water down the pipes, creating water pressure throughout the system.
A network of water mains spread out from the storage and pressurization locations. If the water gets too far away, additional pumping stations are added to keep the pressure up. These are the mains that run down streets, then branch out to buildings. Once the main hookup hits your property line, it becomes your responsibility for maintenance and upkeep.
The opposite of your water main hookup is your sewer main hookup, which gathers all of the wastewater from your house and directs it to the sewers. Unlike the water mains, these aren’t pressurized. Instead, they’re sloped to keep the waste moving, and occasionally have pumping stations that pull the sewage up to a higher level.
The final stage of any water system is the sewage treatment plant. These follow regulations and guidelines set by organizations like the World Health Organization and the EPA to make sure that anything harmful to human health or the environment is removed before the water is released back into the water cycle.