What Type of Water Should I Use in My Coffeemaker? 

Since so much of a cup of coffee is comprised of water, the type of water you choose is integral. Is it okay to use plain water from the tap or should you stick to bottled only? What’s the best type of water for brewing coffee?

Per the Specialty Coffee Association of America or SCAA, the water that goes into coffee should be fresh, clean, and odor-free. The water should contain no more than 250 milligrams per liter of total dissolved solids, no more than 85 milligrams per liter of calcium, and have a pH of 7.5 at most. 

What type of water is that, you ask? That’s exactly what we’ll tell you in this article. Keep reading for more information on whether hard or soft water is better for making your most flavorful cup of coffee yet! 

What’s the Best Type of Water to Use in a Coffeemaker?

If you’re obsessed with making the perfect cup of coffee (which we assume you are if you’re reading this), then you know the SCAA has standards that allow you to do so. These standards are rather stringent, but that’s only to ensure coffee quality. 

So what does the SCAA say about which type of water to use in your coffeemaker? Per the intro, here’s a breakdown of their standards.


If the idea of water having a color is off-putting to you, don’t worry. The SCAA seems to think the same way. The best coffee for brewing should have what they call a “clean color.” In other words, the water can’t be murky or dingy, so no yellow or brown water here!  

Freshness and Cleanliness

The SCAA also advises that coffee aficionados only use fresh, clean water whenever they’re brewing a cup at home. 


If you’ve ever smelled odorous water, then you know what we’re talking about here. It’s certainly not something you feel comfortable drinking. The SCAA recommends that the water you pour into your coffee machine has no odor. 

Sodium Content

Sodium is salt, and a little bit of salt in coffee is not the worst thing for it. You may recall that if you’ve read some of our recent posts. Salt can counteract a bitter cup of coffee, making it taste more palatable. 

The target range for sodium in the water you use to brew coffee is 10 milligrams per liter. That said, if the water contains slightly more than 10 milligrams per liter of sodium, that’s still within the acceptable range. So too is slightly less sodium okay. 

Total Alkalinity 

Total alkalinity refers to how well water can neutralize acids. Alkaline compounds including carbonates and hydroxides are usually present in water and can reduce H+ ions, thus increasing the water’s pH.

The SCAA’s target for total alkalinity in water used to brew coffee is 40 milligrams per liter. Slightly over and slightly under are within the acceptable range too. 

Calcium Hardness

Some water contains more calcium ions than others. This water is usually referred to as hard water. 

Besides calcium, the other minerals that make up hard water include sulfates, chlorides, bicarbonates, and magnesium carbonates.

So what does the SCAA suggest? The target level of calcium hardness in water is 68 milligrams per liter or 4 grains. Up to 5 grains and 85 milligrams per liter of calcium hardness is acceptable.

Water is rated by hardness on a scale. At 60 to 120 milligrams per liter, water is considered only moderately hard. 

This water contains more minerals than slightly hard water and far more minerals than soft water, but it’s not considered hard water (120 to 180 milligrams per liter) or very hard water (more than 180 milligrams per liter).  

Total Dissolved Solids

Total dissolved solids refer to the salts, organic materials, metals, and minerals that dissolve in water. The lower the TDS measurement, the purer the water is, and thus the higher its quality. 

The SCAA has a target goal of water used for coffee to contain only 150 milligrams per liter of TDS. Up to 250 milligrams per liter is okay. 

Total Chlorine

Water can contain chlorine, and the measurement known as total chlorine tells us how much. Total chlorine accounts for both free chlorine and combined chlorine together. 

Free chlorine is the portion of chlorine that hasn’t mixed with water. It’s still actively filtering out microorganisms. Combined chlorine then has been used to filter microorganisms and isn’t actively doing so.

Per the SCAA’s standards, the water you pour into your coffeemaker should have zero milligrams per liter of total chlorine. 


Finally, there’s pH. Many substances are measured on a pH scale, where they can be more acidic or basic aka alkaline. The target goal for water is to have a pH of 7.0, which is perfectly neutral. That said, if the water is slightly more acidic at 6.5 or a little basic at 7.5, that’s okay too. 

Is It Okay to Use Tap Water in a Coffeemaker?

So, keeping in mind the standards that the SCAA has presented, should you continue to use water from your kitchen tap to brew coffee? 

Well, that’s a hard question to answer without knowing more about what type of water exits your tap. 

As we mentioned in the last section, water can be soft, slightly hard, moderately hard, hard, or very hard. Below is the criteria for each. 

Table showing the criteria of the hardness of your water. Less than 1 gpg (or grains per gallon) of calcium carbonate, the water is considered soft. Between 1 and 3.5 gpg the water is considered slightly soft. Between 3.5 and 7 gpg, the water is considered moderately hard. Between 7 and 10.5 gpg the water is hard, and lastly if the calcium carbonate is more than 10.5 gpg then the water is considered very hard.

It’s not like you necessarily get to choose how hard the water is that flows through your taps. The USGS has a map that showcases just how hard water is across the United States.

Soft water that contains fewer than 60 milligrams per liter of minerals is very uncommon and found in only a smattering of states across the country. Moderately hard water up to 120 milligrams per liter is more common but still not prevalent.

Hard water that’s more than 180 milligrams per liter is, unfortunately, the standard across most of the US. 

As you’ll recall from earlier, the SCAA recommends that water contains up to 85 milligrams per liter if you’re using it to brew coffee. At this level, the minerals in your water would enhance the flavor of your coffee.

Once you exceed that recommended range, the water is too hard to make a positive impact on the taste of your brew. 

Plus, as we’ve touched on recently on the blog, calcium hardness can contribute to the development of limescale or scale.

Scale affects how well your coffeemaker works, reducing its capability to brew water at its ideal temperature. Considering that many coffeemakers fail to reach the 205 degrees Fahrenheit mark that brews the best-tasting cup, your coffee can come out tasting all wrong.

That’s not all. Hard water is risky in a multitude of other ways, including:

  • When you do laundry, your clothes always come out dingy. The hard water limits how well soap can lather. Further, soap and dirt can’t be washed out of the clothes when they take a spin in the washing machine. No matter how many times you run your washer, your clothes won’t come out fresher or cleaner.
  • Drinking hard water is not appealing. It tastes dirty and metallic, as though it contains an excess of iron. The bacteria in the water can cause a smell reminiscent of rotten eggs.
  • Showering and bathing are more difficult. It’s not only your washing machine that struggles to lather due to hard water. You won’t be able to suds up your body wash, shampoo, conditioner, or bar soap. Plus, since the hard water isn’t washing this stuff away, residue lingers on your hair and skin. You could feel itchy and have dry skin and hair.
  • Limescale can develop in your coffeemaker and your other appliances as well that use water. From your washer to your refrigerator, kettle, and dishwasher, these appliances will have shorter lifespans than usual. This can cost you thousands of dollars per replacement.
  • Soap scum will develop easily on your shower tiles, bathroom and kitchen sinks, and in your bathtub or shower stall. Check your dishes and glasses as well, as these will develop noticeable chalky spots.
  • One of the worst consequences of hard water is that the calcium deposits can eventually accumulate to such a degree that they block the plumbing in your home. The backed-up pipes can be a nightmare to get repaired or replaced.

Fortunately, if you have hard water, you don’t just have to deal with it. You can get a water softener installed, which is a type of filtration system that brings down the hardness of water. Metal cations, magnesium, and calcium will be a thing of the past, making your water much softer. 

Can You Use Bottled Water in a Coffeemaker?

Water softeners, while a good solution for hard water, are not necessarily the cheapest option. On the lower end, these filters can cost $500, and on the higher end, anywhere from $1,500 to $6,000

As you budget for a water softener, you might decide to use bottled water for your coffeemaker instead.

Bottled water is often distilled, which means it goes through a purification process. The amount of TDS in the water is under 10 particles per million or ppm or 10 milligrams per liter. 

Thus, that’s the problem with bottled water. It contains fewer TDS than what the SCAA recommends. As a reminder, the target TDS for water used for brewing flavorful coffee should contain 150 milligrams per liter. Between 75 and 250 milligrams per liter are acceptable as well.

However, 10 milligrams per liter is far under even 75 milligrams per liter. You might notice that your coffee tastes a bit watered-down compared to using water with a higher concentration of TDS.

That said, coffee brewed with bottled water will always taste better than the same type of coffee brewed with hard water since bottled water has no chlorine. A small number of minerals might enhance the flavor of your coffee, but chlorine will wreck the flavor.

Now, we’re not saying you shouldn’t use bottled water at all when brewing coffee. You might want to switch the brands you buy, though. Shop around for bottled water that contains the required amount of TDS. 

Final Thoughts 

The best type of water to use in your coffeemaker has some minerals but not too many. The water is neither too acidic nor basic, and it never has chlorine. The quality should be clear, colorless, and odor-free. 

By using this type of water when brewing coffee, whether it comes from a bottle or your tap, you can enjoy reliably flavorful coffee! 

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