--- title: "The Water Line Behind an Ice Maker: Tubing, Valve and Pressure" description: "Copper, braided stainless and the plastic tubing makers warn about, saddle valves and local code, the pressure range, slack behind the unit and a five-minute…" url: "https://icemakerrepair.center/guides/water-line-for-an-ice-maker/" date_modified: "2026-09-26" --- Installation and setup # The Water Line Behind an Ice Maker: Tubing, Valve and Pressure A water line for an ice maker is a quarter-inch cold drinking-water supply with its own shutoff valve, run in copper, braided stainless or the maker's approved tubing, with a coil of slack so the unit can be pulled out. GE asks for 40 to 120 psi on models with a filter, and warns that unapproved plastic tubing can crack with age. By [IceMakerRepair.center technical team](https://icemakerrepair.center/authors/technical-team/) Published September 26, 2026 ## At a glance. Behind every plumbed ice maker is a thin tube that stays under full house pressure day and night, for as long as the appliance lives, in a space nobody looks at. What it is made of, where it taps in and how much slack it has decide whether it ever becomes a problem. Read the whole guide ### Size 1/4 inch outside diameter The tubing size in GE's water line instructions for its door ice makers. ### Pressure 40 to 120 psi with a filter GE's range; 20 to 120 psi on its models without a filter, and U-Line's range for its nugget unit. ### Slack behind the unit About 8 feet in three loops GE's figure, so the appliance can come out from the wall without pulling the line. ### Cold water only Never the hot line GE warns that hot water can cause burns and damage the product. In this guide 1. What the line is and what it can be made of 2. The shutoff valve and where it taps into the pipe 3. Pressure and water quality the ice maker expects 4. Routing the line: slack, heat and cold 5. Checking a line you inherited 6. Step by step 7. Questions ## What the line is and what it can be made of The water line for an ice maker runs from a cold drinking-water pipe to the water inlet valve on the back of the appliance, and sometimes through an in-line filter on the way. It is small, a quarter inch across on door and freezer ice makers, and it never gets a rest: GE's installation instructions point out that the line is under pressure at all times. That constant pressure is why the material matters more here than on a faucet supply that sits behind a closed valve most of the day. Three materials turn up behind kitchens and home bars, and each ages differently. ### Soft copper tubing The traditional choice, joined with compression nuts and brass ferrules. It lasts decades if it is not kinked, but a sharp bend from pushing the unit back too hard can crack it, and GE asks for both ends to be cut square so the fitting seals. ### Braided stainless connectors A flexible hose with a stainless mesh outside and fittings crimped on at both ends. U-Line supplies one with its nugget ice maker kit, and its guide says to use a new hose set rather than reuse an old one, and not to add tape or joint compound where the fitting has a rubber gasket. ### Plastic tubing This is the one to look at twice. GE approves only the plastic tubing in its own kits and warns that other plastics can crack or rupture with age and flood a home, and U-Line tells owners not to use a plastic supply line at all. A cloudy, stiff or yellowed plastic line behind an older unit is a replacement waiting to happen. Source: [GE Appliances — Side by Side Owner's Manual and Installation Instructions (49-60198)](https://www.geappliances.com/content/older-pdfs/49-60198.PDF) — 1/4 inch OD copper or GE tubing, ends cut square; line under pressure at all times; only GE-approved plastic, others may crack or rupture; connect to the side of a vertical pipe or top or side of a horizontal one; drill a 1/4 inch hole even with a self-piercing valve or ice production drops; check saddle valves against local code, not permitted in Massachusetts; 40 to 120 psi with a filter, 20 to 120 without; low pressure means repeated cycles; RO supply uses the bypass plug; about 8 feet of slack in three 10 inch loops; no tubing where it freezes; never the hot line; water hammer can cause leaks; installation by a qualified technician; [U-Line — User Guide and Service Manual, UHNB115 nugget ice maker](https://www.u-line.com/userguide/pdf/index/sku/UHNB115-SS01A/) — Braided flexible supply line; use a new hose set; no tape or compound on gasketed fittings; no plastic supply line; 20 to 120 psi; loop the line into two coils; water under 200 ppm TDS and 12 grains hardness, not from a softener ## The shutoff valve and where it taps into the pipe Every ice maker line needs a shutoff valve of its own, somewhere you can reach without moving the appliance: under the sink, in the cabinet next to an undercounter unit, or in the basement directly below. GE's instructions say to connect into the side of a vertical cold pipe when possible, or the top or side of a horizontal one, never the bottom, so the valve does not draw sediment from the pipe. Where the valve taps in decides how much water reaches the ice maker. GE asks for a 1/4 inch hole drilled into the pipe even when the valve is the self-piercing kind, and says a smaller opening can mean reduced ice production or smaller cubes. ### Saddle valves and local code A saddle valve clamps around the outside of a pipe and taps it through a small hole. They come in many water supply kits, which makes them easy to buy and easy to assume are allowed. GE tells installers to check that a saddle valve is allowed by local plumbing code before buying one, and notes that Massachusetts does not permit them at all. Source: [GE Appliances — Side by Side Owner's Manual and Installation Instructions (49-60198)](https://www.geappliances.com/content/older-pdfs/49-60198.PDF) — 1/4 inch OD copper or GE tubing, ends cut square; line under pressure at all times; only GE-approved plastic, others may crack or rupture; connect to the side of a vertical pipe or top or side of a horizontal one; drill a 1/4 inch hole even with a self-piercing valve or ice production drops; check saddle valves against local code, not permitted in Massachusetts; 40 to 120 psi with a filter, 20 to 120 without; low pressure means repeated cycles; RO supply uses the bypass plug; about 8 feet of slack in three 10 inch loops; no tubing where it freezes; never the hot line; water hammer can cause leaks; installation by a qualified technician Close on a braided stainless water line connected to the inlet on the back of a refrigerator. ## Pressure and water quality the ice maker expects How much water reaches the mold on each fill depends on the pressure behind the inlet valve, and so does the size of every cube. GE gives 40 to 120 psi for its models with a water filter and 20 to 120 psi without one, and U-Line gives 20 to 120 psi for its undercounter nugget unit. Below that range, cubes come out small or hollow; GE notes that in homes with low pressure you may hear the ice maker cycle several times to make one batch. Built-in clear-ice and nugget machines are also particular about minerals. U-Line's guide asks for water under 200 ppm of dissolved solids and 12 grains of hardness, never from a water softener, with an in-line filter above those figures. ### Reverse osmosis systems A line teed off an under-sink reverse osmosis system often has too little pressure for an ice maker. GE says that when the supply comes from RO and the unit also has its own filter, the built-in filter should be replaced by its bypass plug, because the two together can cause hollow cubes and slow dispensing. Source: [GE Appliances — Side by Side Owner's Manual and Installation Instructions (49-60198)](https://www.geappliances.com/content/older-pdfs/49-60198.PDF) — 1/4 inch OD copper or GE tubing, ends cut square; line under pressure at all times; only GE-approved plastic, others may crack or rupture; connect to the side of a vertical pipe or top or side of a horizontal one; drill a 1/4 inch hole even with a self-piercing valve or ice production drops; check saddle valves against local code, not permitted in Massachusetts; 40 to 120 psi with a filter, 20 to 120 without; low pressure means repeated cycles; RO supply uses the bypass plug; about 8 feet of slack in three 10 inch loops; no tubing where it freezes; never the hot line; water hammer can cause leaks; installation by a qualified technician; [U-Line — User Guide and Service Manual, UHNB115 nugget ice maker](https://www.u-line.com/userguide/pdf/index/sku/UHNB115-SS01A/) — Braided flexible supply line; use a new hose set; no tape or compound on gasketed fittings; no plastic supply line; 20 to 120 psi; loop the line into two coils; water under 200 ppm TDS and 12 grains hardness, not from a softener ## Routing the line: slack, heat and cold The line has to let the appliance move. GE asks for about 8 feet of extra tubing coiled into three loops about 10 inches across behind the unit, and U-Line asks for two coils, so the unit can be pulled out for cleaning without straining the fittings. Too little slack is the usual reason a line cracks the day someone slides the unit out to mop behind it. Route it where it cannot freeze or cook. GE says not to run ice maker tubing anywhere temperatures fall below freezing, which rules out an uninsulated outside wall in a cold climate, an unheated crawlspace and a garage in winter. - Coiled slack behind the unit, not a straight taut run. - No kinks where it passes through the floor or the cabinet back. - Clear of the compressor and condenser, which run warm. - Away from exterior walls and unheated spaces that drop below freezing. - The shutoff valve reachable with the appliance in place. Source: [GE Appliances — Side by Side Owner's Manual and Installation Instructions (49-60198)](https://www.geappliances.com/content/older-pdfs/49-60198.PDF) — 1/4 inch OD copper or GE tubing, ends cut square; line under pressure at all times; only GE-approved plastic, others may crack or rupture; connect to the side of a vertical pipe or top or side of a horizontal one; drill a 1/4 inch hole even with a self-piercing valve or ice production drops; check saddle valves against local code, not permitted in Massachusetts; 40 to 120 psi with a filter, 20 to 120 without; low pressure means repeated cycles; RO supply uses the bypass plug; about 8 feet of slack in three 10 inch loops; no tubing where it freezes; never the hot line; water hammer can cause leaks; installation by a qualified technician; [U-Line — User Guide and Service Manual, UHNB115 nugget ice maker](https://www.u-line.com/userguide/pdf/index/sku/UHNB115-SS01A/) — Braided flexible supply line; use a new hose set; no tape or compound on gasketed fittings; no plastic supply line; 20 to 120 psi; loop the line into two coils; water under 200 ppm TDS and 12 grains hardness, not from a softener ## Checking a line you inherited Most people never see the line installed; it came with the house or the previous appliance. A five-minute look, with the unit pulled a short way out and a flashlight, tells you most of what you need. Look at the material, the fittings at both ends and the floor under the valve. Water hammer, a bang in the pipes when a valve snaps shut, is worth mentioning too. GE warns that it can damage appliance parts and lead to leaks, and asks for a plumber to cure it before a line is connected. - Plastic tubing that is cloudy, yellowed or brittle to the touch. - Green or white crust on a compression nut: a slow weep. - A saddle valve with rust or mineral streaks below it. - A stain or soft spot in the floor or cabinet under the valve. - No slack at all behind the unit. Source: [GE Appliances — Side by Side Owner's Manual and Installation Instructions (49-60198)](https://www.geappliances.com/content/older-pdfs/49-60198.PDF) — 1/4 inch OD copper or GE tubing, ends cut square; line under pressure at all times; only GE-approved plastic, others may crack or rupture; connect to the side of a vertical pipe or top or side of a horizontal one; drill a 1/4 inch hole even with a self-piercing valve or ice production drops; check saddle valves against local code, not permitted in Massachusetts; 40 to 120 psi with a filter, 20 to 120 without; low pressure means repeated cycles; RO supply uses the bypass plug; about 8 feet of slack in three 10 inch loops; no tubing where it freezes; never the hot line; water hammer can cause leaks; installation by a qualified technician ## Where to stop Tapping into a pipe, replacing a saddle valve, sweating or cutting copper and running a new line through a floor or wall are plumbing jobs, and GE's own manual says the ice maker hookup should be done by a qualified technician. Close the valve and book if a fitting is weeping, a plastic line is brittle, or the valve will not turn fully off. Written by [IceMakerRepair.center technical team](https://icemakerrepair.center/authors/technical-team/). The technicians sent out when an ice maker visit is booked on this site. They write from what they find at the supply valve, along the fill tube, in the ice bin and at the drain, and they check it against the maker's own manuals wherever one is published. Sources: [GE Appliances — Side by Side Owner's Manual and Installation Instructions (49-60198)](https://www.geappliances.com/content/older-pdfs/49-60198.PDF) · [U-Line — User Guide and Service Manual, UHNB115 nugget ice maker](https://www.u-line.com/userguide/pdf/index/sku/UHNB115-SS01A/) ## Step by step. Four steps, in the order worth doing them. 01 ### Find the valve Trace the line from the back of the ice maker to its shutoff and confirm you can reach it with the unit in place. 02 ### Identify the material Copper, braided stainless or plastic, and whether any plastic is the maker's approved kind. 03 ### Check both fittings Look for crust, drips or staining at the valve and at the inlet on the back of the unit. 04 ### Check the route Make sure there is coiled slack and no kink, and that the run avoids unheated walls and floors. For the heart of your home. ## Questions owners ask. ### Can I use the hot or softened water line to feed the ice maker? No to hot water: GE warns it can cause burns and damage the unit. Softened water depends on the maker; U-Line says its nugget ice maker must not be fed from a softener. ### How long should an ice maker supply line last? No maker publishes a lifespan for the line. Copper and braided stainless last many years if not kinked; brittle or discolored plastic should be replaced now. ### Is a saddle valve acceptable for an ice maker line? It depends on local code. Many kits include one, GE says to confirm it is allowed first, and Massachusetts does not permit them. ### Why does the line need so much slack behind the unit? So the appliance can be pulled out for cleaning or service without stretching the tubing or loosening a fitting. GE asks for about 8 feet in three loops. ## The problems behind it. Each has a page of its own: what it usually means and the causes in the order worth checking. [All 17 problems](https://icemakerrepair.center/problems/) Water on the floor or near power ### Ice Maker Water Line Leaking Behind the Cabinet 6 causes, cheapest first Problem ### Ice Maker Making Small or Hollow Cubes 6 causes, cheapest first Problem ### No Ice Coming From the Ice Maker 7 causes, cheapest first ## When it needs a technician. The repairs on the right are where this guide ends when the checks do not settle it. ### Water filter and supply line service The filter, the shutoff valve and the thin line that bring water to the ice maker, checked for flow, leaks and age, with a worn line or saddle valve replaced and a new filter seated properly. ### Ice maker water inlet valve repair The electric valve that lets water into the ice maker, tested and replaced when it will not open, opens only partway, or keeps dripping after it should have closed. ### Diagnostic visit A visit that traces the water from the supply valve to the bin and back out through the drain, and names the one part that stopped the ice before anything is ordered. ## More in installation and setup. Running a water line to an ice maker, what to expect from the first batches of ice after installation, and how to set up an ice maker in a home that sits empty for weeks at a time. [The whole section](https://icemakerrepair.center/guides/installation-and-setup/) Water lines, first ice and a unit left alone ### First Ice After Installation: How Long, What to Throw Away, What to Check Why a door or freezer ice maker needs most of a day, the batches and glassfuls that go down the sink, the sounds of a new unit and the setup details that keep the bin empty. Water lines, first ice and a unit left alone ### An Ice Maker in a Vacation Home: Closing Up and Opening Again Switching off and closing the valve for a short absence, draining before a winter without heat, the undercounter and countertop shutdowns, reopening in order and leak sensors between visits. Guides ### All 18 guides Six sections, by what you are trying to find out. --- **[Read on the site: The Water Line Behind an Ice Maker: Tubing, Valve and Pressure](https://icemakerrepair.center/guides/water-line-for-an-ice-maker/)** **[Book a visit with IceMakerRepair.center](https://icemakerrepair.center/schedule/)**