The Structure of Water Infrastructure

Go on a water journey with us to find out how it moves from ground water to the tap!

By: Erica Lies

Much like a person taking a long, arduous journey, the fresh water in our taps must take an extended journey of its own to get to our homes. This trip includes three basic segments: where the water starts, its source; the phases of water treatment; and then (the final leg) the pipes it must cross to get to our doors. During this journey, water is exposed to many other substances, some of which, sadly, decide to go along for the ride. A few of those stowaway substances go for the whole ride, because water treatment doesn’t capture 100 percent of the contaminants that can get into our waters.

If this throws you into a panic over what substances you may be drinking, rest assured that understanding how our water delivery systems work can go a long way toward feeling like you have some control over that life-giving substance that flows through your tap. So, let’s go on a journey of our own now to learn the basics of where our water comes from, how it gets treated, and how it comes to our doors (or rather, kitchens and bathrooms).

Straight to the source: where's our water drawn from?

The second most used water source is groundwater which sits underground in large aquifers, getting pumped out through wells. In both instances, the water is then taken to a water treatment plant.

Before it comes into our homes, water passes through many substances and channels, leaving it open to contamination from multiple sources — most of them before the water reaches a treatment plant, some after, and a few even during. The Water Education Foundation explains that the various materials water may pass through can contain, “sulfur, zinc, or arsenic-laden formations. Groundwater can pick up contamination from fertilizers, septic tanks, mine drainage, and naturally occurring elements, industrial chemicals and metals such as arsenic and chromium.” As if that weren’t enough, they also point out that rivers and streams are more likely than, say, an underground aquifer, to have microorganisms that can cause disease. That’s why water must go through a middle journey before it gets to the public, and that middle journey is the water treatment plant.

The many stages of treating public water

Most likely, your local water treatment facility is operated and run by your local city government or municipality. An important little law called the Safe Drinking Water Act requires that all water be cleaned before it’s delivered to the general population.

In order to do that, water is put through several steps of treatment. The first focuses on removing solid particles that are in the water. This is called coagulation and flocculation. The Centers for Disease Control explains that in the coagulation process, chemicals with a positive charge are added to the water in order to bind to dirt and other sediments, which have a negative charge. Those chemicals bind to dirt or other dissolved materials that are in the water and this makes them heavier, so they sink. Which leads to the next step: sedimentation.

Sedimentation is much like one of those fancy juices you can buy that warn you to shake them before drinking. When a body of liquid is left untouched for a period of time, larger particles separate to the bottom, and in the case of water, treatment plants use that to filter out those particles. They’re called “floc.” Hence the term “flocculation.”

Next, the water is disinfected to kill pathogens that it may contain, and this is where a lot of chemicals get added into the water in order to clean it. It sounds counterintuitive, but adding chlorine and chloramine (the two most used for disinfection) kills many of the microorganisms and other toxins that can get into water, such as parasites and viruses.

Once it’s processed, that water is delivered to the city system. If you’d like to learn the particular treatment process in your local municipality, most utilities share their water treatment process with the public. For the intrepid types, there’s a great listing of every water treatment plant in the U.S. where it’s possible to learn more about your local water treatment and its processes.

Unfortunately, however, there are some things that water treatment filtering and disinfection have a little more trouble in banishing from our water, and they’re things that we’re adding into the system every day ourselves.

What doesn't get filtered out

As an increasing number of Americans take pharmaceuticals daily, traces of those drugs are ending up in our water supplies. In fact, the Scientific American claims that this happens through various means. In some cases, it’s because households flush extra medication down their toilet. In most instances, medications get into the water supply when the drugs that aren’t absorbed into a human’s blood stream get eliminated through urine and feces. Although we may fool ourselves that wastewater completely disappears when it leaves our homes, it’s often cleaned and reused. Unfortunately, however, while water treatment can clean and sanitize our H2O, it’s been shown to leave some drug traces behind, and that means it’s very likely to be in the water coming to our kitchen sinks.

Of course, Scientific American also points out it’s not exactly the fault of wastewater treatment plants that they can’t filter all of these pharmaceuticals. They weren’t designed to, and the numbers of drugs that the average American takes has increased far faster in recent decades than the city budgets that might allow the plants to upgrade. There’s no need to panic, as the drugs being found in water are in significantly low amounts. However, it’s the volume that has experts concerned, particularly as they aren’t sure what effects low amounts of so many drugs entering the water will have.

PFOA, PFOS, and PFAS are substances that are commonly found in non-stick cookware, pesticides, textiles, and even leather. They’re man-made chemicals that were in wide usage until the mid-2000s. The EPA required they be phased out of product manufacturing by 2015, but there are still plenty of older products remaining out there that are letting these microplastics get into our water. Harvard researchers even found that 6.5 million Americans’ water had levels of PFOA that exceeded Federally accepted levels. Which would be fine, except that those same Harvard researchers also found that exposure to trace amounts can interfere with the immune system, and greater exposure can lead to cancer, heart disease, and even possible birth defects.

Water delivery

Supply, processing, and distribution of water are the three critical components in delivering those liquid globules from their source into that fancy shower head with the amazing water pressure. If any of these pieces of water infrastructure is affected along the way, it can present a threat to the broader system, so it’s helpful to understand the systems your water is passing through after it leaves the treatment plant.

There are two major pipe systems that deliver water to your sink: main lines and services lines. Main lines are pipes maintained and controlled by cities and municipalities. They bring water from treatment plants to the property lines of individual residences. Service line pipes connect to these municipal lines and bring water up to and inside homes, and these pipes are the homeowner’s responsibility to maintain. It’s important to understand the differences between the two kinds of pipes in order to further understand where and how your home’s water can be affected by that very series of serpentine series of metal tubes. Most main lines in the U.S. no longer contain lead pipes, but replacing and updating household pipes falls to the homeowner, who may or may not have the money for replacement or the desire to deal with construction in their home.

Lead pipes: the danger beneath

The phrase “lead pipes” may sound outdated, but unfortunately, they’re not entirely in society’s rearview mirror. In fact, many houses built before 1984 still have lead pipes or lead soldering in their service lines.

Unfortunately, many of the elements that travel through water pipes can also corrode lead — yes, even water. Acidity, alkalinity, and water’s oxygen molecules can increase lead levels in the water. And since extreme weather can send many new water contaminants into the supply and affect its content, lead levels in the water can fluctuate as it travels into your home. Vox recently reported, “Water is naturally corrosive — its oxygen molecule will break down lead piping. Then the lead will seep into the water source. If utilities don’t carefully balance water chemistry and treatment methods, tainted water can enter a community water system.”

Last stop: protecting your household water

It might be disheartening hearing that water treatment can’t protect consumers from every possible thing that may enter a complicated system, but there are some steps citizens can take to protect themselves and at least stop contributing to the problem. For one, don’t dispose of excess medications by flushing them down the toilet. Many pharmacies have take back programs, and can dispose of them properly for you, sometimes for a small free. Use a water filter or water filtration system in your home. Carbon filters have shown effectiveness in removing pharmaceuticals from wastewater, but can be cost prohibitive for cities to purchase for wide usage. There are, however, many direct to consumer carbon filters, and they’re at least another layer of defense. Ideally, get one that’s certified by NSF. Finally, if you live in an older home and it’s cost-effective for you, look into the piping in your home and its service lines. And if you find lead piping and an affordable way to fix it, get that done, just for peace of mind.



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