Get Started with a Free Water Consultation

Where Does Well Water Come From?


Most well water comes from underground reservoirs called aquifers — natural “storage tanks.” These tanks are filled with groundwater, which originated from precipitation that seeped through the earth as part of the water cycle. Professional drilling equipment opens access to the aquifer and allows private wells to draw from this water source.

Of course, there’s a lot more to know about well water, where it comes from and what that means for your home’s water quality. Read on to find out more about the responsibilities that come with private wells.

Where Wells Get Water

The exact source of your well water depends on where you live, how your well was drilled and even weather patterns in your area. However, the water cycle plays an important role in almost all private wells:

Step One: Precipitation
Precipitation is water that gathers in the atmosphere and falls as rain, snow, sleet or hail. Because salt doesn’t evaporate, precipitation is always fresh water, even if it came from the ocean.

Of course, the process of precipitation is a round trip; most of this water will likely head right back to the atmosphere soon. However, some of it sinks through layers of soil and rock to become part of a different cycle.

Step Two: Natural Filtration
Any liquid form of precipitation can filter through layers of the earth. Despite the name, this kind of filtration doesn’t necessarily remove contaminants from the water; while some particles are too big to pass through, other material — such as sediment or mineral content — is added along the way.

The result of this natural movement and filtration is groundwater — water that exists in saturated zones underground and fills any spaces in rock and soil. A space called the water table sits right above these zones and acts as the boundary between two areas: unsaturated, which contains oxygen; and saturated, where all available space is filled with water. The saturated zone stops at a layer of impenetrable rock.

Although you may have heard that groundwater acts like an underground river, the truth is that the process is more like a sponge. Underground materials have pores that “suck up” the water and hold it there.

Step Three: Storage
Some groundwater exists in such small amounts that it’s not useful for private wells. In other areas, however, there’s enough space between rocks and sediment for groundwater to flow naturally. That’s what turns a saturated zone into an aquifer.

Groundwater moves between three and 25 inches (or seven and 60 centimeters) per day. This means that, far from being a fast-moving river, groundwater could actually stay put in an aquifer for thousands of years.

However, that doesn’t necessarily mean a certain area has an endless water supply. Aquifers must be refilled by precipitation in a process called “recharging.” If people use water faster than the recharge rate, often due to expanding agricultural needs combined with frequent droughts, aquifers can run dry.

Step Four: Access
To access groundwater held in an aquifer, you need professional drilling equipment. These drills bore through the unsaturated zone and water table — but they can’t stop there.

Imagine you have a glass of water. You put a straw at the top and don’t push it all the way down. You’d be able to take a few good sips — but soon the water level would be far below your straw and you wouldn’t be able to reach it anymore.

This is similar to what happens if a well is too shallow. The key is to dig so deeply that gravity pulls groundwater down into the empty hole, where it can then be pulled up by your well’s pump system.

Think back to that glass of water. You’ve pushed your straw all the way down, but now your significant other has put their own straw in the glass. This is a good metaphor for private wells because, while each household generally has its own well and pump system, multiple wells can draw from the same aquifer. The more people use a water source, the faster it will deplete. It’s rare for aquifers to run dry, but it’s still helpful to understand the science behind this possibility.

City Water vs. Well Water

City and well water supplies go through different journeys to get to their respective taps. For example, although some public water systems draw from groundwater aquifers, most use surface water — including rivers, lakes and reservoirs. Surface water is replenished by rain and snow, and some of it evaporates into the atmosphere to become new precipitation.

Whether a city water system takes water from a river, reservoir or other source, it has a responsibility to provide water treatment. The U.S. Safe Drinking Water Act and the Guidelines for Canadian Drinking Water Quality establish limits on certain contaminants, while various public health organizations enforce those limits.

For example, for most North American water systems, the treatment process includes two significant additives:

  • Chlorine: Chlorine is used to disinfect drinking water and kill bacteria and viruses that may negatively impact human health.
  • Fluoride: Water fluoridation is intended to help protect dental health in both children and adults.

Underground pipes called water mains move the water from treatment facilities to local communities. From there, a home’s private plumbing takes over and transports water to the tap.

Generally speaking, city and well water are similar. However, their journeys have just enough differences to make private wells feel like a new undertaking for many first-time users.

Common Well Water Issues

Wells use different water sources and don’t include municipal treatment. As such, private well owners are responsible for their own water quality. And while common municipal water issues such as chlorine smells or tastes won’t be present, well water comes with some of its own considerations. Examples include:

Hard Water

Water hardness can affect both city and well water supplies, but it’s more common in the latter. This problem occurs when your water has too much calcium and magnesium, leading to spotty dishes, mineral buildup, irritated skin, dry hair and more.


As the fourth most abundant element in the Earth’s crust, iron is part of nature — which means it could be part of your aquifer and well system, too. Iron is often responsible for rust-colored stains on your faucets and in your bathtub or shower. It can also make your tap water taste metallic.

Hydrogen Sulfide

Sulfur bacteria are a part of the decay process in the natural environment. They create hydrogen sulfide, which, in turn, creates a rotten egg smell in your water.

Other Contaminants

Remember, well water isn’t chlorinated, which means it hasn’t been disinfected or treated before reaching your tap. Depending on where you live and how your well is constructed, different contaminants may enter your water supply — for example, total coliform bacteria (including E. coli) from nearby farmland.*

Want to learn more about well water? Download our FREE eBook today.

Best Water Solutions for Wells

While some problems and contaminants may be more common in well water, there’s good news: You can protect your water quality with a water filter for well water, a well water softener, or both. Take a look at the top water solutions for private wells:

Regular Water Testing

The U.S. Environmental Protection Agency recommends having your well water tested at least once a year. You should have additional tests after significant events such as well damage or repair, big storms or potential contamination.

Water Softening

Water softeners help eliminate hardness issues by attracting calcium and magnesium particles and using salt water to flush them away. You can choose a well water softener system based on hardness levels, the amount of water you use and the type of features you want (for example, smartphone notifications when it’s time for a salt refill).

Water Filtration

The two best options when it comes to choosing well water filtration systems: whole-home and reverse osmosis.

  • Whole-home filtration systems treat all your tap water, targeting specific contaminants such as iron, hydrogen sulfide, arsenic and more.
  • Reverse osmosis systems treat your drinking water. These comprehensive systems can address odor, taste and appearance issues as well as a broad range of contaminants.

Have Questions About Your Well Water? Start Here

Whether you’re using a private well for the first time or just want to learn more about your home’s water quality, a free, in-home water test and consultation is the best place to start. In 30 minutes or less, you’ll have all the information you need about water hardness levels, potential contaminants and other common well issues. Better yet, your Culligan® expert will recommend solutions based on your location and test results.

Get started today by scheduling your water test and consultation.

*Contaminants may not be present in your water.

Find A Location Near Me


Schedule Your Free
In-Home Water Test

Get better water in your home by scheduling an appointment with your local Culligan Water Expert.

Our Products

blue wave
Water Softeners

Water Softeners

With any of our soft water systems, get more out of your water-using appliances while spending less on energy and detergent.

View Products

Water Delivery

Water Delivery

There’s never been a better time to enjoy the convenience of scheduled bottled water deliveries from the Culligan® Water Experts

View Products

Water Filtration Systems

Water Filtration Systems

Culligan's water filtration systems have improved water quality for thousands of families worldwide.

View Products