Part 02 · What's in your water
Test strips or a TDS meter: what each one tells you
A TDS meter gives one number for everything in the water. A strip reads one thing at a time. Which you need depends on what your maker measures.
The short answer
A TDS meter gives one number for everything dissolved in the water. A hardness strip reads the minerals that form scale. Meticulous says a TDS meter alone isn't enough to judge scale risk. Use the test that matches the limits your machine's maker sets.
What a TDS meter reads
A TDS meter measures how well water conducts electricity and turns that into one number for everything dissolved in it: calcium, magnesium, sodium, chloride and the rest. It can't tell you which of those are present.
From the maker
MeticulousMeticulous Espresso
“A TDS meter alone is not enough. It reports total dissolved solids without telling you what they are. Water at 120 ppm TDS could be perfectly balanced or a scale hazard depending on its composition.”
La Marzocco gives its TDS range in both ppm and microsiemens, the unit a conductivity meter reads:
From the maker
La MarzoccoLa Marzocco machines (La Marzocco Deutschland FAQ, German market)
“Water selection – manufacturer specifications ... TDS (total dissolved solids) value of 90–150 ppm (parts per million), or 160–260 µS (microsiemens)”
Makers that set TDS limits
A TDS meter is the right tool when your maker gives a TDS figure. Several do:
| Maker | The maker's words | Source |
|---|---|---|
| BrevilleBreville espresso machines (US support article; no models named) | Water that lacks in mineral content can contribute to sourness and acidic taste in the espresso, it is recommended to use water that has mild amount of minerals like soft filtered water, spring water, well water, these types of water ideally measure in between 50-150 ppm (parts permillion) in dissolved solids. | Source for Breville, Breville espresso machines (US support article; no models named) (opens in a new tab)Saved October 28, 2026 |
| Decent EspressoDE1 (all models), Bengle | Less than 30ppm is safe and you will not need to descale ever | Source for Decent Espresso, DE1 (all models), Bengle (opens in a new tab)Saved October 22, 2026 |
| Decent EspressoDE1 (all models), Bengle | Less than 120ppm is safe but you will need to descale annually | Source for Decent Espresso, DE1 (all models), Bengle (opens in a new tab)Saved October 22, 2026 |
| Decent EspressoDE1 (all models), Bengle | More than 120ppm can be safe, but you will need to descale often: at least twice a year, or significantly more often, depending on the water | Source for Decent Espresso, DE1 (all models), Bengle (opens in a new tab)Saved October 22, 2026 |
| Decent EspressoDE1 (quickstart guide) | Buy an inexpensive TDS (Total Dissolved Solids) meter. It measures the hardness of your water, which should be 120 ppm or lower to minimize scaling in your espresso machine. | Source for Decent Espresso, DE1 (quickstart guide) (opens in a new tab)Saved October 28, 2026 |
| La MarzoccoLa Marzocco home machines | For optimum machine performance, the water properties should fall within the following parameters: T.D.S | ppm | 90 | 150 | Source for La Marzocco, La Marzocco home machines (opens in a new tab)Saved October 22, 2026 |
Show all 13
| Maker | The maker's words | Source |
|---|---|---|
| La MarzoccoLa Marzocco machines (La Marzocco Deutschland FAQ, German market) | Water selection – manufacturer specifications ... TDS (total dissolved solids) value of 90–150 ppm (parts per million), or 160–260 µS (microsiemens) | Source for La Marzocco, La Marzocco machines (La Marzocco Deutschland FAQ, German market) (opens in a new tab)Saved October 28, 2026 |
| La MarzoccoLa Marzocco machines (La Marzocco North America water specification; it names no model) | La Marzocco Water Specification ... T.D.S. ppm 90 150 | Source for La Marzocco, La Marzocco machines (La Marzocco North America water specification; it names no model) (opens in a new tab)Saved October 28, 2026 |
| La MarzoccoLa Marzocco machines (Technical Center Water Calculator; names no model) | SUGGESTED LA MARZOCCO TDS RANGE: BELOW 150PPM | Source for La Marzocco, La Marzocco machines (Technical Center Water Calculator; names no model) (opens in a new tab)Saved October 28, 2026 |
| La MarzoccoLa Marzocco machines (Technical Center Water Calculator; names no model) | TDS lower than 75ppm: Effects on espresso: weak body, tart taste. Effects on equipment: water becomes aggressive against espresso equipment’s materials and speed up corrosion phenomenon caused by other additional factors. | Source for La Marzocco, La Marzocco machines (Technical Center Water Calculator; names no model) (opens in a new tab)Saved October 28, 2026 |
| RancilioRancilio home espresso machines (US article; names the Silvia Pro X) | are the water quality guidelines we recommend you follow for both the sake of your machine, and your taste buds... Total Dissolved Solids (TDS): 30-150 ppm (parts per million) Total Hardness: 2-3 gpg (grains per gallon) pH: 6-8 Chloride: 0 ppm Chloramine: 0 ppm Silica: <5 ppm | Source for Rancilio, Rancilio home espresso machines (US article; names the Silvia Pro X) (opens in a new tab)Saved October 28, 2026 |
| Slayer EspressoSLAYER espresso machines (support article; names no model; says 'All SLAYER Espresso Machines') | Water Treatment Requirements ... TDS: 50-200 ppm | Source for Slayer Espresso, SLAYER espresso machines (support article; names no model; says 'All SLAYER Espresso Machines') (opens in a new tab)Saved October 28, 2026 |
| Victoria ArduinoEagle One Prima (user handbook) | WATER SPECIFICATIONS ... tds (total dissolved solids) level between 50 – 250 ppm. | Source for Victoria Arduino, Eagle One Prima (user handbook) (opens in a new tab)Saved October 28, 2026 |
What a test strip reads
A hardness strip changes color with the amount of calcium and magnesium, the minerals that form scale. Other strips read chlorine, and drop-count kits read alkalinity or chloride. Each test reads one thing, so check what a kit measures before you buy it.
Some makers put strips or a test kit in the box:
| Maker | The maker's words | Source |
|---|---|---|
| Brevillethe Barista Touch Impress BES881 | Your Barista Touch™ Impress espresso machine comes with water test strips, so you can determine the hardness of your water and whether or not your water filter should be changed. | Source for Breville, the Barista Touch Impress BES881 (opens in a new tab)Saved October 28, 2026 |
| La MarzoccoLa Marzocco home machines | We recommend using the water testing kit that comes with your new La Marzocco before you use the machine. | Source for La Marzocco, La Marzocco home machines (opens in a new tab)Saved October 22, 2026 |
Matching the tool to your maker
- If your maker's limit is hardness in °dH, gpg or ppm, use a hardness strip or a hardness drop test.
- If your maker also sets carbonate hardness or alkalinity, use a kit that reads KH.
- If your maker gives TDS, use a TDS meter as well.
- If your maker sets a chloride limit, you need a chloride test. Hardness strips and TDS meters don't read it.
Your machine's card on the espresso machines page shows which measurements its maker sets. Our test kits page lists what each kit measures.
Sources
Every quote above is the maker's own wording, saved with its link and date. We link only to the makers' own manuals and pages.
- Meticulous, Water for Your Meticulous: Preventing Scale and Getting the Best Taste (Meticulous Home, Inc. Help Center; written by Roy Raanani, July 29, 2026). maker help center (opens in a new tab), saved October 28, 2026.
- La Marzocco, La Marzocco Deutschland FAQ, 'Which water should I use?' (lamarzocco.com/de/en/faq/, article modified 2026-02-11). maker site (La Marzocco Deutschland) (opens in a new tab), saved October 28, 2026.
- Breville, Breville US Support article ka0QU000002VvldYAC (water for espresso machines), page text. breville.com (opens in a new tab), saved October 28, 2026.
- Decent Espresso, Water recommendations for the DE1 and Bengle (Decent docs; created 2025/11/24, updated 2026/10/20). decentespresso.com (opens in a new tab), saved October 22, 2026.
- Decent Espresso, DE1 Quickstart Guide, section 'What kind of water should I use?' (Decent docs; created 2026/10/26, updated 2026/10/27). decentespresso.com (opens in a new tab), saved October 28, 2026.
- La Marzocco, La Marzocco Water Specifications (web page, La Marzocco Ireland/UK site; no US version found). lamarzocco.com (opens in a new tab), saved October 22, 2026.
- La Marzocco, La Marzocco Water Specification (1-page PDF, La Marzocco North America, Seattle; file created 2015-09-16; linked as 'La Marzocco Water Specification PDF' from La Marzocco Home USA's plumb-in article dated 07/09/2026). maker document (La Marzocco North America) (opens in a new tab), saved October 28, 2026.
- La Marzocco, Water Calculator (La Marzocco Technical Center, techcenter.lamarzocco.com, page footer (c) 2023; linked as 'Water Calculator' from the La Marzocco IE water page and the LM Deutschland FAQ). maker site (La Marzocco Technical Center) (opens in a new tab), saved October 28, 2026.
- Rancilio, Rancilio Group North America, "Home Espresso Water Options" (web article, ranciliogroupna.com). maker US subsidiary site (Rancilio Group North America) (opens in a new tab), saved October 28, 2026.
- Slayer Espresso, SLAYER Water Treatment Requirements (Slayer support knowledge base article; created 2017-09-20, modified 2025-07-10). maker support site (opens in a new tab), saved October 28, 2026.
- Victoria Arduino, EAGLE ONE PRIMA user handbook (IT/EN/FR, 100 pages; PDF created 2021-11-09; manufacturer Simonelli Group); maker's manual hosted by a retailer (argo.webstaurantstore.com). maker manual (opens in a new tab), saved October 28, 2026.
- Breville, Check and set water hardness (Breville My Products page, BES881). breville.com (opens in a new tab), saved October 28, 2026.
Questions
Can a TDS meter measure hardness?
Not directly. It reads everything dissolved, including salts that don't form scale. Meticulous puts it this way: water at 120 ppm TDS "could be perfectly balanced or a scale hazard depending on its composition."
Which test should I buy first?
Start with the measurement your maker sets. For most prosumer machines that's hardness, so a hardness strip. Your machine's card shows what its maker sets.
Mineral & Steam does not certify water as safe, guarantee protection from scale, corrosion or equipment damage, or recommend a machine as an overall purchase. It compares the water information you provide with documented manufacturer water requirements and shows the basis and limits of that comparison.
Keep reading
What's in your waterHow to read your city's water report for espressoYour utility's yearly report usually has the numbers a machine maker cares about. Here is where to look, what some large cities list, and where reports fall short.What your machine needs°dH, gpg or ppm: how to read a maker's hardness limitMakers write hardness in German degrees, French degrees, grains per gallon or ppm. Here is how they convert, and where a number can mislead.