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What Is in Tap Water & Where Does It Come From?

Scott Winfield
Last Updated on
by Scott Winfield

Tap water qualifies as water that comes from a faucet or another water outlet in a home. This water is sometimes not purified or treated enough, meaning that some tap water is not safe to drink.

Tap Water

Where Does Tap Water Come From (US)?

The United States gets its drinking tap water from surface water and groundwater.

Surface water refers to streams, rivers, lakes, and other natural sources. It is essentially any body of water that is visible to you. Precipitation and run-off are the two major suppliers to surface water.

Groundwater refers to water below the ground. Water seeps through ground and pools in any cracks and crevices in the soil below. Groundwater supplies about 51% of United States’ drinking water supply.

While surface water is relatively easy to access, groundwater requires some work to get to. To reach groundwater, contractors drill into the ground to create a well. The wells then pump the water up to your home.

Where Does Canada Tap Water Come From?

Canadia tap water comes from surface water and groundwater, as well. Canadians also use groundwater influenced by surface water.

Groundwater influenced by surface water means that rivers or lakes supply the groundwater. The water from these bodies of water seeps into the ground, creating this groundwater supply.

Where Does Australia Tap Water Come From?

Australia’s tap water comes from stored surface water that resides in reservoirs.

Australia is a dry continent/country, which means they are susceptible to droughts quite often. Because of this, Australia only uses a small amount of groundwater for tap water. There is not enough water below the surface to supply Australian residents.

As climate change worsens, Australia’s drinkable water supply is decreasing. Due to this, Australia is getting creative and finding other ways to make water drinkable.

Seawater desalination has played a large role in Australia’s drinkable water supply.

In this process, ocean water goes through a filter to remove solids. Then, the water is moved into a tank where reverse osmosis occurs. Reverse osmosis is a process in which dissolved minerals get separated from the water. The final step involves conditioning or treating the water, so it is suitable for consumption.

Since ocean water surrounds Australia, desalination provides access to an endless supply of potentially drinkable water. A few desalination plants are set up across Australia to aid in water supply replenishment.

Where Does Sydney Tap Water Come From?

Sydney’s tap water mostly comes from Lake Burragorang, which is protected by the Warragamba Dam.

Around 80% of Sydney’s water comes from Lake Warragamba. Smaller surface water sources (other lakes and rivers) and desalination make up the other 20% of Sydney’s water supply.

Sydney sources water from the surrounding oceans and processes the water in its desalination plant called the Sydney Desalination Plant. This plant is especially beneficial to Sydney residents when there is a drought.

What Is in Tap Water?

Various minerals and contaminants are in tap water. However, your location determines what and how much contaminants is in your water.

Some common minerals and contaminants found in tap water include:

  • Sediment
  • Small amounts of metals such as lead, iron, cadmium, and arsenic
  • Human waste
  • Chemicals such as nitrate, mercury, and fluoride
  • Minerals such as sodium, calcium, magnesium, chloride, bicarbonate, and sulfate

This might sound scary, but not everything on this list is detrimental to your health.

The minerals in water are healthy for you as long as they are not present in high amounts. Fluoride is good for your teeth, as it keeps their enamel strong. As for the other contaminants, they are not as healthy.

Keep in mind that not all tap water has these things. Some tap water is safer than others. It all depends on where your water is specifically coming from.

How Is Tap Water Treated?

Water treatment is different depending on where you live. The options usually include filtration and disinfection with chlorine or desalination.

Filtration and Disinfection With Chlorine

Filtration and Disinfection With Chlorine
Filtration and Disinfection With Chlorine

The typical filtration process has the water go through a series of steps.

It starts with coagulation, in which chemicals are added to the water to neutralize dirt and sediment. These chemicals combine with sediment to make the particles larger. Then, flocculation makes the particles even larger.

The water then moves onto sedimentation, where the (now large) sediment pieces separate from the water. Now the water is pushed through multiple filters. The filters remove germs, bacteria, and chemicals.

The final step is disinfection. Chlorine kills any remaining bacteria, viruses, and other harmful things. Water treatment plants sometimes use UV light to kill germs rather than chlorine.



As explained before, desalination plants work to filter out the salt, bacteria, and other minerals from seawater. Without this process, seawater is undrinkable.

Well Water Treatment

Well Water Treatment
Well Water Treatment

The two previous ways of treating tap water apply if you have city water. If you live in a rural area, you most likely have a well. Well water comes directly from the ground and does not go through government-funded treatment. It is up to you to filter and treat your water.

Well water treatment usually involves an in-home treatment unit. These units include filtration systems, water softeners, distillation systems, and disinfection.

The groundwater is pushed through filters to remove impurities similar to how city water is filtered.

Water softeners remove hard water minerals from water. If you don’t remove the minerals, it will buildup in your sinks, showers, toilets, etc.

Distillation systems boil the water to separate impurities from the water. The steam gets collected and condensed, leaving the impurities behind.

Disinfection takes place with chemicals like chlorine or physical disinfectants. Physical disinfectants include UV light, electronic radiation, and heat.

Is It Safe To Drink Tap Water?

Tap water is safe to drink in most cities. City or public water treatment is regulated. Well water treatment is where it gets tricky.

City water treatment plants require supervision and regulations. The water gets tested to make sure it meets specific safety standards. These safety precautions make water safe to drink.

Well water treatment is not regulated since it is private property. This is why most people with wells have filtration systems in their homes. If the well water is filtered, it is safe to drink.

Which Country Has the Best Tap Water?

Denmark currently holds first place for the cleanest tap water in the world.

For many years Switzerland was top of the list. But, according to recent performance tests, Denmark has taken over. However, Switzerland is still in the top ten.

Denmark has groundwater protection sites and policies. Due to this, pollution and contaminants do not reach the water supply. Treating Denmark’s water is not necessary.  Denmark residents can drink right from the tap because their groundwater is the cleanest it can be.

What Are the Healthiest Alternatives To Tap Water?

Bottled spring or purified water are your best options if your tap water is unsafe to drink.

Springwater is groundwater. Most companies put their bottled springwater through a filtration process to remove bacteria and chemicals.

Purified water goes through multiple filtration processes to make it safe for consumption.

Healthiest Alternatives To Tap Water
Healthiest Alternatives To Tap Water

Bottled spring water and purified water are regulated and must meet strict safety standards before they are safe to sell to the public. These water types are always safe to drink by the time they reach you.

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Scott Winfield
Scott Winfield
My name is Scott Winfield and researching and writing about water filters and other strategies to purify water has become my full time passion in recent years. I'm glad that you found our site and you can look forward to authoritative and well researched content here to help you get the best in water.
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