Is Well Water Hard Water?

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Well water isn’t always hard. But because it comes from the ground rather than surface sources like lakes and reservoirs, it’s more likely to contain hard water minerals.

Hard water occurs when minerals like calcium, magnesium, and manganese dissolve into water (by binding with oxygen and hydrogen). When water spends long stretches underneath the ground, substances from the soil will combine with it, and might require a well water filter before being safe to drink.

Across most of the US, the soil that surrounds well water contains high levels of hard minerals. As a result, most wells tend to produce hard water.

What is well water hardness?

If you have ever spent time digging a deep hole at the beach, you’ll know that you can only dig so far before water starts to pour in. That depth—when a body of water naturally collects—is known as the water table.

In many underground locations, a large amount of water will collect above the water table. These locations are called aquifers, and it’s from these underground stores that well water is pumped. Unlike artificial reservoirs constructed to contain surface water, aquifers are natural formations made from rainwater that seeps through the soil.

Generally speaking, the closer to sea level the water table is, the less time water will spend in an aquifer, giving it less chance to absorb hard minerals. But when water tables create large aquifers many hundreds of meters below the earth, water can sit for many years and become much harder.

The type of bedrock that an aquifer sits atop also has a large effect on water hardness. Water tables made of porous rock containing lots of calcium produce harder water than tables made from igneous rock like granite.

Is my well water hard or soft?

The short answer is that, if your well is located in North America, then your water is likely to be hard. According to measurements of water hardness made by the USGS, most US wells produce water that’s considered between “moderately hard” and “hard”.

This is because there are large portions of porous bedrock across the country, where minerals can more easily dissolve into water. Calcium-rich soil and resulting hard groundwater water is commonly found on the East Coast, in many southern states, and across the Midwest. For instance, Kentucky has a greater number of limestone mines than any other state, and predictably, experiences water that registers as “hard” or “very hard”.

Soft water is found more on the West Coast than in the East, though it’s also prevalent in New England and other areas with a lot of non-porous bedrock, which can’t be eroded by aquifers so easily. Water that makes its way into wells from glacial formations or by flowing through igneous rock is almost always softer.

You can also taste the difference between hard and soft water when the mineral content is high enough. In fact, just like expensive spring water, natural groundwater with lots of calcium and magnesium is considered healthier than softer water by many people.

How do I tell If my well water is hard?

Hard water isn’t usually identifiable by appearance, but you can detect hardness by how water tastes and feels—as well as the effect it has on pipes and other surfaces.

Hard water often causes a scratchy or itchy feeling on skin and hair after bathing. It may also make hair more frizzy. It also frequently causes spots and watermarks on dishes and glasses, especially after running them through the dishwasher.

If you find that you often need to use more laundry detergent than the bottle recommends, it may be because hard minerals in your well water are preventing soap from lathering. At the same time, a buildup of calcified scale in your laundry machine and other hot water appliances is a sure sign of hard water.

Water hardness testing

The only surefire way to know if your well water is hard is to test it. A simple, 30-second way to perform a hard water test is to fill a plastic bottle with some of your water and a drop of dish soap. Shake the bottle, let it settle, then see how many suds form. The fewer suds, the harder the water. Extremely hard water produces nearly no suds and turns water cloudy.

To go a step above the suds bottle test, you can buy a well water testing kit, available for 10-50 dollars online or in large home product stores. Local colleges and water treatment companies may also offer free water testing. These tests reveal the presence of dissolved substances in a water supply, including hard minerals as well as any chemicals, metals, and microscopic organisms.

Most well water tests judge hard water using a metric determined by the U.S. Geological Survey. According to USGS measures, water is slightly hard when it contains up to 120 mg of calcium per liter, and very hard when it contains over 180 mg.


  • Many people use the terms hard water, groundwater, and well water interchangeably. It’s true that most well water in the US is hard.
  • This is because much of the country is built on soil and bedrock that contains hard minerals such as calcium and magnesium. Water from underground aquifers that sit on this bedrock slowly absorbs these minerals, increasing its hardness.
  • You can find out if you have hard water in your well by performing a simple suds test, or by purchasing a home testing kit.

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