Is Hard Water Destroying Your Coffee’s Flavor?

Written by: Garrett Oden

hard water destroys coffee flavor

Want to know one of the biggest reasons coffee shop coffee often tastes better than home brewed coffee? I’ll give you a hint: this one doesn’t have anything to do with the coffee.

Coffee is 99% water. Great water opens the pathway to great coffee. It has nuance, complexity, and richness.

Bad, hard water brews disappointing coffee, whether you’re using pre-ground coffee from a can or this year’s Cup of Excellence winner from Honduras. Bad water produces dulled flavors, muddy acidity, and a lack of sweetness. There’s no trick or technique to making bad water brew stellar coffee.

Read: Why Fresh Coffee Is The Best Coffee

I know what it’s like to be disappointed by my coffee at home, and reworking my water habits made a world of difference. My goal with this blog is to help you discover whether your water source is damaging your coffee’s flavor and what steps there are to fix it.

The Best Water For Coffee Brewing

Not all water is equal.

Some water sources have a high alkalinity. Some water sources have a high concentration of calcium and other minerals. Some water sources give off an odor. Some have dirt.

Read: Learn How To Taste Coffee

Don’t assume that your water quality is fine because you live in an area with regulations. Ranger, Texas has record levels of lead. Lubbock, Texas water is literally off the charts when it comes to calcium hardness. Well water near San Antonio, Texas sometimes has a sulfury smell. All three places are within hours of each other - and all three have dramatically different water.

That being said, the best water for coffee brewing is not 100% pure. A small amount of minerals is actually helpful when it comes to extracting flavors and aromas from your coffee.

The Specialty Coffee Association of America released some research on coffee and water quality a few years ago. Here’s what they discovered.



Acceptable Range


Clean, Fresh, Odor Free


Clear Color

Total Chlorine

0 mg/L

TDS (total dissolved solids)

150 ml/L

75-250 mg/L

Calcium Hardness

4 grains or 68 mg/L

1-5 grains or 17-85 mg/L

Total Alkalinity

40 mg/L

Near 40 mg/L



6.5 to 7.5


10 mg/L

Near 10 mg/L

The best water for coffee brewing is clear, odorless, chlorine-free, mildly acidic, and contains a slight concentration of various minerals. It’s not 100% pure, reverse osmosis water.

The best water is also always fresh from the tap. After 12 hours of sitting out or so, carbon dioxide messes with the water, giving it an off taste and reducing pH levels.

Now that you know what the target is, let’s take a look at your own water source.

Compare Your Own Water Source

Cities in America are required by law to collect and publish data on water quality. Most of these reports are available online for anyone to read. To find your city’s data, head on over to Google and search for the following: “[CITY, STATE] Water Report”.

Read: Blades VS Burrs: What Is the Best Type of Coffee Grinder?

water for coffee

Find the most recent report and do some digging. Chances are there’s a lot of data that’s not relevant to your coffee, so it may take a few minutes to find the things you’re looking for and write them down.

Now you can compare your local water source to the target range.

If your water source falls within the acceptable quality range, your coffee isn’t being harmed by bad water. You can confidently continue to use your regular source.

If your water source is beyond the acceptable range, your coffee is suffering in quality and flavor to some degree. While this is unfortunate, it means your coffee’s flavor has plenty of room to improve with a minor adjustment.

2 Ways To Fix Your Water

Here are some ways you can keep bad water from tainting your coffee.

The first option is to filter your local tap. If your problem is a high concentration of minerals (a very common problem - especially with calcium), you can attach a water softening filter onto your faucet or use a filtering pitcher. To fix this hard water problem, you’re looking at $20-100.

Read: 5 Things That Ruin Your Coffee

This method is pretty easy but tends to lose effectiveness because it’s so easy to forget to change the filters and perform regular maintenance. These filters can only do so much though, and if your calcium hardness level is off the charts (like mine) you may want to consider the next option.

Buying soft water with reusable jugs is a great way to get the water you need without wasting dozens of plastic bottles. Although 100% pure water isn’t ideal, it’s better than water that has a very high concentration of minerals, alkalinity, or pH.

In my research, I’ve found that spring water tends to come pretty close to the SCAA water quality targets, though pure water is still going to perform pretty well.

Read: What Makes Specialty Coffee Special?


Water quality is more important than most people realize. It’s 99% of coffee, after all. Whether you’re a casual drinker or a loyal snob, hard water will kill your coffee flavor, and great water will improve your coffee dramatically. Take care of your water and your water will take care of you.

But, of course, if you don't start out with great coffee beans, your water quality won't matter one bit.

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Happy brewing!