Part 04 · Caring for the machine
Plumbing in an espresso machine: what makers ask of your water line
Pressure, flow, and a filter or softener before the machine. What La Marzocco, Nuova Simonelli, ECM, Profitec and Rocket ask for.
The short answer
Makers that publish plumbed-in requirements give a pressure range and often ask for a filter or softener. La Marzocco suggests 45 to 80 psi. Nuova Simonelli's Oscar asks for 2 to 4 bar. ECM and Profitec recommend a softener or filter on the line.
Pressure and flow
Makers that publish plumbed-in requirements usually give a pressure range for the water line, and some give a flow rate:
| Maker | The maker's words | Source |
|---|---|---|
| La MarzoccoLa Marzocco machines (La Marzocco North America water specification; it names no model) | Suggested pressure and flow rate from water mains: 45 to 80 psi (3 to 5 bar) and 8 Liter per minute. | 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 SpazialeS1 Vivaldi (LUCCA A53), mains connection | The water mains pressure must be within the range of 1 and 6 bar. | Source for La Spaziale, S1 Vivaldi (LUCCA A53), mains connection (opens in a new tab)Saved October 28, 2026 |
| Nuova SimonelliOscar (sold in the US as Oscar II), tank and direct-connection versions | Water line pressure between 2 - 4 bar and water to be cold; | 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 |
| Nuova SimonelliOscar (sold in the US as Oscar II), tank and direct-connection versions | Min flow rate: 200 l/hr; | 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 |
Pressure is written in bar or psi. One bar is about 14.5 psi, so La Spaziale's 1 to 6 bar is about 15 to 87 psi (our conversion).
A filter or softener on the line
A plumbed-in machine draws straight from your water line, so makers often ask for treatment before it:
| Maker | The maker's words | Source |
|---|---|---|
| ECMTechnika V Profi PID | To avoid calcification of the machine a water-softener is recommended. | Source for ECM, Technika V Profi PID (opens in a new tab)Saved October 28, 2026 |
| La PavoniLa Pavoni Cellini Evolution (water supply connection); the same PDF is linked for the Cellini Classic, which has no water supply connection | It is recommended that you install a water softener on the machine water supply system. | Source for La Pavoni, La Pavoni Cellini Evolution (water supply connection); the same PDF is linked for the Cellini Classic, which has no water supply connection (opens in a new tab)Saved October 28, 2026 |
| ProfitecPRO 800 (CM500012-00) | To avoid calcification of the machine, a water filter is recommended. | Source for Profitec, PRO 800 (CM500012-00) (opens in a new tab)Saved October 28, 2026 |
| Rocket EspressoGiotto FAST R, Mozzafiato FAST R (mains connection) | The manufacturer recommends the use of an inline filter. | Source for Rocket Espresso, Giotto FAST R, Mozzafiato FAST R (mains connection) (opens in a new tab)Saved October 28, 2026 |
Not every maker means the same thing by "softener". Several ECM and Profitec manuals also say water from sodium-based ion-exchange softeners isn't recommended. Water softeners and espresso machines sets the two side by side.
Plumbing in from an RO system
Some makers sell a kit for connecting to pressurized water, including from an RO system:
From the maker
Decent EspressoDE1 series (DE1PRO, DE1XL, discontinued DE1PLUS) and Bengle
“With our plumbing kit, you can connect your espresso machine to pressurized water, such as you'd get from an RO-system. It is compatible with all the models in the DE1 series (including the DE1PRO, the DE1XL, and the discontinued DE1PLUS) and with Bengle.”
Whether straight RO water suits a machine is a separate question, and makers disagree. See distilled or RO water.
Which machines can be plumbed in
Some machines take a water line out of the box, some need a kit, and some come in tank and plumbed versions. The espresso machines page filters for the ones whose makers say they can be plumbed in, and each card says how.
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 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 Spaziale, La Spaziale MANUAL FOR USE AND MAINTENANCE S1 VIVALDI, LSC 010 Rev 00 Ed. 07/2014 (LUCCA A53 edition; PDF created 2015-02-25; hosted on a Shopify store file host and by Clive Coffee). maker document on retailer site (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.
- ECM, ECM Technika V Profi PID user manual, 02-2021; ECM PDF hosted by Whole Latte Love. maker document on retailer site (opens in a new tab), saved October 28, 2026.
- La Pavoni, La Pavoni instruction manual for New Cellini Evolution / New Cellini Classic (usermanual/114 and /116, same PDF, created 2026-02-03). maker manual (opens in a new tab), saved October 28, 2026.
- Profitec, Profitec PRO 800 user manual, item no. CM500012-00, 02-2022 (ba-pro800.pdf, profitec-espresso.com). profitec-espresso.com (opens in a new tab), saved October 28, 2026.
- Rocket Espresso, Rocket GIOTTO-MOZZAFIATO FAST user and maintenance manual, multilingual (PDF created 2026-01-30, 42 pp.; Rocket document hosted by Seattle Coffee Gear). maker document on retailer site (opens in a new tab), saved October 28, 2026.
- Decent Espresso, How to connect your plumbing kit to the machine (Decent docs). decentespresso.com (opens in a new tab), saved October 28, 2026.
Questions
What water pressure does a plumbed-in espresso machine need?
Your maker sets it. La Marzocco suggests 45 to 80 psi, Nuova Simonelli 2 to 4 bar for the Oscar, and La Spaziale 1 to 6 bar for the S1 Vivaldi.
Can I plumb in from an RO system?
Some makers sell kits for it, such as Decent Espresso. Whether straight RO water suits the machine is a separate question, and makers disagree.
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.