Part 01 · What your machine needs
What water does my espresso machine need?
Most makers say something about water. Far fewer give a number you can check. Here is what they publish, and how to read it.
The short answer
Whatever its maker says, and makers don't agree. Some publish exact limits for hardness, alkalinity, chloride, TDS or pH. Many give advice with no number. Of the 230 machines we cover, 43 have a maker limit our water check can use.
What makers write about
Espresso machine makers write about water because minerals in it can leave scale in boilers and pipes, and some dissolved salts can corrode metal. When a maker gives numbers, they usually cover some of these:
- Hardness. Mostly calcium and magnesium, the minerals that form scale.
- Alkalinity, sometimes called carbonate hardness or KH. Makers such as La Marzocco and Meticulous list it beside hardness.
- Chloride. Several makers set a ceiling because of corrosion. See chloride limits.
- Chlorine and chloramine, the disinfectants many cities add.
- Total dissolved solids (TDS), one number for everything dissolved in the water.
- pH, and sometimes iron, silica or sulfate.
Few makers cover all of them. La Marzocco publishes one of the fullest tables for its home machines:
From the maker
La MarzoccoLa Marzocco home machines
“For optimum machine performance, the water properties should fall within the following parameters: T.D.S | ppm | 90 | 150”
The table below shows every TDS figure we've saved from a maker. The ranges don't agree, which is why one water can be within one machine's stated requirements and outside another's.
| Maker | The maker's words | Source |
|---|---|---|
| AscasoAscaso Baby T Plus (mains connection) | T.D.S. 90-150 ppm | Source for Ascaso, Ascaso Baby T Plus (mains connection) (opens in a new tab)Saved October 22, 2026 |
| AscasoAscaso home machines sold by Ascaso-USA: Dream PID, Steel DUO PID, Steel DUO PLUS PID, Baby T Plus (linked under WATER SPECIFICATIONS on each resource page) | T.D.S. ppm 90 150 | Source for Ascaso, Ascaso home machines sold by Ascaso-USA: Dream PID, Steel DUO PID, Steel DUO PLUS PID, Baby T Plus (linked under WATER SPECIFICATIONS on each resource page) (opens in a new tab)Saved October 28, 2026 |
| 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 |
Show all 20
| Maker | The maker's words | Source |
|---|---|---|
| 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 |
| 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 |
| MeticulousMeticulous Espresso | As a rule of thumb, based on total dissolved solids: Under ~30 ppm TDS: scale will essentially never form. | Source for Meticulous, Meticulous Espresso (opens in a new tab)Saved October 28, 2026 |
| MeticulousMeticulous Espresso | 30–120 ppm TDS: descale about once a year. | Source for Meticulous, Meticulous Espresso (opens in a new tab)Saved October 28, 2026 |
| MeticulousMeticulous Espresso | Over 120 ppm TDS: descale at least twice a year, or more often depending on your water. Better yet, switch to a water source in the target range. | Source for Meticulous, Meticulous Espresso (opens in a new tab)Saved October 28, 2026 |
| Nuova SimonelliOscar (sold in the US as Oscar II), tank and direct-connection versions | TDS (Total Dissolved Solids) level between 50 - 250 ppm; | Source for Nuova Simonelli, Oscar (sold in the US as Oscar II), tank and direct-connection versions (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 |
| SynessoES.1 | Failure to adhere to the listed water quality standards will void the warranty of this machine. ... Total Dissolved Solids (TDS) 30 - 200 ppm (parts per million) | Source for Synesso, ES.1 (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 |
Advice or a limit
Most makers say something about water. Far fewer give a number you can check. "Use filtered water" is advice. "At most 4 °dH" is a limit. Rocket Espresso's manuals give both kinds, in different places:
From the maker
Rocket EspressoRocket Espresso machines (manual)
“Use fresh, filtered water to fill the reservoir. Do not use distilled water.”
Of the 230 machines we cover, 43 have a maker limit our water check can use. For the other 187, each machine's page quotes whatever its maker does say, so you can read it for yourself.
Written for one model, or for a range
A maker's limit can change from one model to the next, and from one edition of a manual to the next. La Marzocco's current manuals ask for chloride under 30 mg/l:
From the maker
La MarzoccoLinea Mini 2023 (serial MI)
“the quantity of chlorides be less than 30mg/l”
The manual for the earlier Linea Mini, made from 2015 to 2022, gave a different figure:
From the maker
La MarzoccoLinea Mini (2015-2022, serial LM)
“the quantity of chlorides be less than 50mg/l”
So we keep each figure with the model it was written for. A rule a maker wrote for another model is shown on a machine's page, labeled, but it doesn't decide a result until the maker's own words show that it applies.
How we use a maker's numbers
The water check compares your water with the maker's limits one measurement at a time. There is no overall score, so a good hardness reading can't hide a high chloride reading.
When a maker writes a figure in a unit we can't read without guessing, such as "ppm" with no basis, we show the quote but don't use it to decide. How to read a maker's hardness limit explains why.
Where to start
- Find your machine on the espresso machines page. Its card shows the maker's water limit, or says the maker publishes none our check can use.
- Get your water's numbers from your city's yearly report or a test strip. How to read your water report shows what to look for.
- Put both into the water check.
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.
- 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.
- Ascaso, Ascaso Baby T manual MAN.36 V11 (2023), English section. ascaso.com (opens in a new tab), saved October 22, 2026.
- Ascaso, Ascaso USA Water Specification (one-page PDF, Ascaso-USA; PDF created 2015-09-16, modified 2020-05-08). US distributor document (Ascaso-USA) (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 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.
- 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.
- 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.
- Nuova Simonelli, Simonelli Group OSCAR instruction handbook, IT/EN/FR/DE/ES (file OscarII-Manual-All.pdf; PDF created 2022-10-27, 112 pp.; on the US distributor's site, simonelliusa.com). maker manual on US distributor site (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.
- Synesso, ES.1 Water Quality Standards (1-page PDF 'ES.1 water-quality-standards', created 2023-04-17, synesso.com). maker document (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.
- Rocket Espresso, Rocket Espresso user manual (Rocket PDF hosted by Seattle Coffee Gear; created 2026-02-23). maker document on retailer site (opens in a new tab), saved October 22, 2026.
- La Marzocco, linea mini 2023 manual MAN.34.05.1 EN-FR V1.0 (PDF created 2023-09-22), hosted on home.lamarzoccousa.com. maker manual (opens in a new tab), saved October 28, 2026.
- La Marzocco, linea mini manual MAN.12.0.1 EN-IT-FR-DE-ES V1.1 (PDF created 2015-04-02), hosted on home.lamarzoccousa.com. maker manual (opens in a new tab), saved October 28, 2026.
Questions
Is there one water standard for every espresso machine?
No. Each maker sets its own, and the figures differ. La Marzocco asks for 90 to 150 ppm TDS for its home machines, while Decent Espresso says water under 30 ppm TDS means you'll never need to descale. Use your own machine's figures.
Does the Specialty Coffee Association set limits for espresso machines?
This site uses machine makers' own guidance. Figures you'll often see, such as chloride under 30 ppm, come from makers like La Marzocco and Slayer, not from the SCA.
My machine's maker gives no number. What then?
Its page on this site quotes whatever the maker does say. You can still check your water against that advice by hand, and a hardness strip is a sensible start. Find your machine.
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.