What Kind of Water for Espresso Machines?

Last updated on March 10th, 2025 at 12:14 pm

Ever wonder why your espresso doesn’t always taste the same, even when you use the same beans?

When I first started making espresso at home, I barely thought about water quality. I just filled up my machine with regular tap water and called it a day.

But then, I started noticing something: some days, my espresso tasted bright and balanced, while other times, it was dull or even bitter.

At first, I blamed my beans or my grinder settings, but then my barista friend pointed out the one thing I had completely overlooked: water.

He explained how the minerals and impurities in tap water can alter the taste of espresso and even cause scale buildup inside the machine.

After experimenting with different types of water, I saw a huge improvement in flavor and how my machine performed. If you’ve never thought about the water you use in your espresso machine, you’re not alone!

In this guide, I’ll break down what kind of water is best for espresso, how to avoid damaging your machine, and simple ways to improve your water quality for better coffee. So, let’s dive in!

Why Water Quality Matters for Espresso Machines?

If you’ve ever wondered why your homemade espresso doesn’t taste as good as the one from your favorite café, water quality might be the problem.

It’s easy to focus on coffee beans, grind size, or machine settings. However, water makes up 98% of your espresso. For this reason, using the wrong kind can ruin both flavor and machine longevity.

How Water Affects Espresso Taste?

The right balance of minerals in your water is crucial for extracting the best flavors from your coffee.

Ideally, your water should have enough minerals to enhance body and sweetness but not so much that it interferes with extraction.

• Too many minerals (hard water)? Your espresso can turn out bitter, over-extracted, or even slightly metallic. This happens because excess minerals interact with the coffee compounds, resulting in an unpleasant taste.
• Too few minerals (soft or distilled water)? Your espresso will taste flat, dull, or weak. The fact is minerals play a role in extracting oils and flavor compounds from the coffee grounds. So if they’re missing, the shot lacks complexity.

A good middle ground is water with a Total Dissolved Solids (TDS) level of 75-150 ppm. This ensures just enough minerals to support extraction without overpowering the flavor.

Water’s Impact on Your Espresso Machine

Beyond taste, bad water can damage your espresso machine. The reason is hard water, which is high in calcium and magnesium.

This causes scale buildup, leading to clogged pipes, poor temperature regulation, and potential machine failure.

If you’ve ever noticed chalky white residue inside your water reservoir or steam wand, that’s scale forming. Over time, it reduces efficiency and requires frequent descaling to prevent breakdowns.

Problem with Soft Water

On the flip side, soft water can be too corrosive. If water has been excessively softened or lacks minerals altogether, it can erode metal components inside your espresso machine, particularly in models with brass or copper boilers.

Notes: Using the right water balance protects your espresso machine, reduces maintenance needs, and extends its lifespan. So, you’ll end up saving you money on repairs in the long run.

What’s The Best Water for Espresso Machines?

Using water with the right balance of minerals and pH ensures optimal extraction. Meanwhile, it prevents scale buildup or corrosion inside your machine.

Ideal Water Composition for Espresso

For the best espresso flavor and machine performance, your water should meet these standards:

Factor	Ideal Range	Why It Matters
pH Level	Around 7.0 (neutral)	Prevents corrosion and damage to internal components.
Total Dissolved Solids (TDS)	75-150 ppm	Ensures proper extraction; too high = bitter, too low = weak.
Hardness	50-100 ppm	Balances mineral content to avoid excessive scaling.
Chlorine & Impurities	Completely removed	Prevents unpleasant flavors and machine wear.

Getting this balance right means better-tasting espresso and a healthier machine in the long run.

Best Water Options

If you’re not sure what water to use, here are some of the best choices:

Filtered Tap Water – Removes chlorine and heavy metals while keeping essential minerals for a balanced extraction. Using a carbon filter or built-in filtration system helps maintain the right water quality.

Bottled Spring Water – A solid option, but check the label! Some brands have high mineral content, which can cause scale buildup. I suggest looking for bottled water with TDS between 75-150 ppm.

Water with a Proper Filtration System – Reverse osmosis (RO) systems with a re-mineralization filter are excellent. The reason is RO removes impurities, but without re-mineralization, it can result in flat-tasting espresso.

Water to Avoid in Espresso Machines

Let’s talk about the types of water you should avoid and how to fix any potential issues.

Distilled or Pure Reverse Osmosis Water

Why? Lacks essential minerals. This may give you weak extraction, poor flavor, and flat espresso. Plus, minerals help draw out your coffee’s sweetness, body, and complexity. Without them, you get a dull, lifeless shot.

Fix: If you use reverse osmosis (RO) water, make sure to add a remineralization filter. This reintroduces key minerals like calcium and magnesium, ensuring better extraction without scale buildup.

Hard Tap Water

Why? High in calcium and magnesium, which causes scale buildup inside your espresso machine. Over time, this can clog the internal pipes, affect water flow, and make temperature regulation inconsistent. As a result, you may get bitter and over-extracted espresso.

Fix: If you have hard water, use a water softener or a filtration system to reduce mineral content while keeping just enough for good extraction. Also, many espresso machines have built-in water filters, which should be replaced every 2-3 months for best performance.

Bottled Mineral Water

Why? Many bottled waters have a high mineral content (TDS over 250 ppm), which can cause scale buildup and potentially damage your espresso machine. While they might taste great for drinking, they aren’t ideal for brewing espresso.

Fix: Look for bottled water with a TDS of 75-150 ppm. This range maintains good flavor while preventing excessive scaling.

Three Good Bottled Water Options for Espresso Machines:

Crystal Geyser Alpine Spring Water – Has a balanced TDS level of around 100 ppm. For this reason, it’s a great choice for espresso machines.

Volvic Natural Spring Water – A solid option with low mineral content, helping maintain espresso flavor without scaling.

Mountain Valley Spring Water – Slightly on the higher end of the ideal range. But still an ideal choice for espresso flavor and machine longevity.

How to Test Your Water for Espresso Machines

Well, testing your water is the easiest way to avoid any problems. So here are some methods:

Simple Home Test

If you want to get a quick snapshot of your water’s quality, a TDS meter is a great starting point. TDS (Total Dissolved Solids) meters measure the number of dissolved minerals in your water. This helps you see if it falls within the ideal range of 75-150 ppm for espresso machines.

Anything higher, and you risk scale buildup. Otherwise, it is too low, and your coffee might taste flat.

Another easy test is checking for chlorine content. The fact is chlorine can give your espresso an unpleasant and chemical-like taste. For this reason, it’s best to remove it.

A simple water testing kit from a hardware store can tell you if chlorine lurks in your tap water. If there is, a carbon filter can easily fix the issue.

Professional Water Testing

If you want a more detailed analysis, taking a sample to a local water testing facility is the way to go. These labs can provide precise breakdowns of pH levels, mineral content, and potential contaminants.

Some coffee machine manufacturers even offer water testing services. This is especially useful if you have a high-end espresso setup that requires specific water quality to maintain warranty coverage.

Preventing Scale Buildup & Maintaining Your Machine

If you want your espresso machine to last for years and keep producing great coffee, regular maintenance is non-negotiable. Even if you’re using the best water possible, scale buildup is inevitable over time.

Without proper care, limescale can clog internal components, reduce water flow, and even affect temperature stability—all of which lead to poor espresso quality.

Luckily, keeping your machine in top shape doesn’t require much effort, just a few simple habits.

Regular Descaling

Even if you’re using filtered or low-mineral water, trace amounts of minerals can still build up inside your machine’s boiler, pipes, and group head.

Over time, this leads to scale buildup, which can affect water temperature and pressure, throwing off your espresso shots.

To prevent this, descaling should be done every 2-3 months or more frequently if you have hard water. It’s best to use a manufacturer-approved descaling solution rather than DIY vinegar mixtures, which can be too harsh on metal components and leave behind an unpleasant taste.

The process usually involves running the solution through the machine, letting it sit, then flushing with fresh water. Trust me, it’s worth it—your espresso will taste better, and your machine will last longer.

Using In-Machine Water Filters

Many modern espresso machines come with built-in water filtration systems, which help reduce scale buildup by filtering out excess minerals and impurities. These filters can make a difference if your local water supply is high in calcium or chlorine.

To keep your machine running smoothly, it’s crucial to replace water filters every 2-3 months. A worn-out filter won’t be as effective, meaning minerals will sneak into your machine and cause problems over time.

If your espresso machine doesn’t come with a built-in filter, consider using an external water filtration system or a filtering pitcher to improve your water quality before filling the reservoir.

Note: A little routine maintenance goes a long way. By staying on top of descaling and filter changes, you’ll enjoy better espresso, fewer repairs, and a longer lifespan for your machine.

Last Thoughts

Have questions about maintaining your espresso machine? Struggling with scale buildup or unsure about the right water to use? I’d like to hear your questions in the comments and with that voilà!