Answers · The supply line and the filter
What Water Pressure Does a Sub-Zero Ice Maker Need?
The short answer
It depends on the model: Sub-Zero quotes either 20 to 100 psi or 35 to 120 psi, and its UC-15I undercounter ice maker asks for 20 to 80 psi.
Check in this order
- Find your model's figure under plumbing requirements in its Sub-Zero installation guide.
- Ask a plumber to measure the pressure; Sub-Zero gives owners no gauge or procedure.
- Watch for small or hollow cubes, or a fill tube that keeps freezing, since both point to low or unsteady pressure.
- Pour a cup of water behind the curtain of an undercounter machine; a changing spray means pressure is short.
Past this line it is a technician's job Sub-Zero Repair Tacoma, (206) 472-1140
Behind the answer
The Designer and PRO installation guides both list 35 to 120 psi. Steadiness counts as much as the figure: Sub-Zero names pressure swings in the home as one cause of a frozen fill tube.
Related questions
Can the pressure be too high?
Yes, each range has a ceiling as well as a floor: 100 or 120 psi depending on the model, and 80 on the UC-15I. Where the house runs above it, a plumber fits a regulator. If the ice still misbehaves after that, call Sub-Zero Repair Tacoma on (206) 472-1140.
Does a well or reverse osmosis change what the ice maker needs?
The figure stays the model's own, but Sub-Zero wants it steady at all times behind reverse osmosis. If ice production keeps stopping there or on well water, it points to a pressure booster or regulator, chosen with a plumber or the system's provider rather than guessed at.
- Signed
- Marta Fennimore
- Role
- Refrigeration technician — ice systems and water supply
- In the trade
- 12 years
- Holds
- EPA 608 certified
- Checked
- Sep 18, 2026