Do I need 3/4 inch supply lines for the Ella fast-fill faucet?

You do not have to run 3/4 inch lines to use an Ella fast-fill faucet, but Ella recommends them, and the two 3/4 inch by 5 foot braided stainless steel supply lines that ship with every 2-piece and 5-piece faucet set are built for that size. Your existing 1/2 inch house lines will work; 3/4 inch lines simply fill the tub faster. The hoses and valves themselves are described in What Are the Supply Lines and Shut-Off Valves on a Walk-In Tub?, and this page covers the sizing decision, what it means for fill time, where the shut-off valves should go, and the adapters older plumbing may need.

Line Sizes in Ella's Published Material

Three different pipe and hose sizes come up around an Ella faucet, and it helps to see them side by side before your plumber opens a wall.

The practical reading is simple. The faucet end of the system is always 3/4 inch on current sets, so the only question is what your house delivers to the shut-off valves. If the home already has 3/4 inch lines, or you are opening the wall anyway, 3/4 inch is the recommended choice. If the home has 1/2 inch lines and replacing them is not in the plan, the faucet still works, and the difference shows up as a longer fill rather than a problem.

What 3/4 Inch Lines Mean for Fill Time

Ella's flow figures describe what the faucet can do, not what every home will see. The 2-piece single-lever set is designed for 16 GPM at 60 PSI, and the 5-piece set with separate hot and cold levers is designed for 18 GPM. Those figures assume 60 PSI and ideal plumbing. In real homes, fill time runs 7 to 15 minutes depending on tub size and your water supply, and Ella notes that it takes about 10 minutes to reach a level where the hydro jets can be used and about 6 minutes more to reach the overflow. Our guide to how long it takes to fill a walk-in tub walks through the full picture.

Pipe size is one of several things that decide where you land in that range:

• House water pressure, since the GPM ratings are stated at 60 PSI.
• Pipe size, which is why 3/4 inch lines are recommended and 1/2 inch lines fill more slowly.
• The distance from the water heater to the tub.
• Hot water being used elsewhere in the house at the same time.
• How many gallons your model holds with you seated in it. Most standard-size Ella tubs hold 65 to 107 gallons unoccupied, and you typically use 30 to 75 gallons per bath once seated.

Hot water supply matters as much as line size. A fast faucet only helps if the water stays warm for the whole fill, and the general guidance from the team is that the average walk-in tub usually calls for a 75 gallon or larger water heater, with the maximum capacity heater available for your house as the recommendation. A tankless heater should be rated at 11 GPM or more. Running 3/4 inch lines to a water heater that runs out of hot water part way through the fill does not solve the problem, so have your contractor assess pressure, pipe runs and heater capacity together before installation day.

Where the Shut-Off Valves Go

Shut-off valves, also called stop valves, are not included with the faucet set. Your plumber supplies them and places them close to the tub. Ella's recommendation is that the valves be reachable through the front apron access panels or through a wall access panel. The reason is future service: if a supply line or the faucet ever needs attention, your plumber can close two valves at the tub instead of shutting down water to the whole house.

Plan the valve location while the tub is still out of the alcove, because the front apron panels are the natural access route on an Ella tub and the plumbing has to be arranged so a hand and a wrench can reach the valve bodies through them. Know where your shut-off valves are before you need them. During warranty activation your installer leak-checks the supply lines with the diverters on, and that is a good moment to ask to see the connections and the valves while the access panel is open.

One more planning note: a tub ordered without an Ella faucet does not receive Ella supply lines, since the lines travel with the faucet set. In that case the lines come with whatever faucet you purchase, so check the contents of that purchase before your plumber arrives.

Connecting the Lines Without Creating a Leak

The 2-piece fast-fill faucet installation video shows the supply line connection on a tub that arrives with pre-drilled holes. Before the supply lines go on, the installer checks that the faucet gasket is seated correctly. The hot supply line carries red markings and the cold carries blue markings, and both lines have reverse threads. Each line is hand tightened, then given one quarter to one half extra turn with a wrench. The same hand-tight-then-snug approach applies to the house side of each line at the shut-off valve.

Over-torquing is the mistake to avoid. Ella's guidance is that connections are made hand-tight and then gently snugged with a wrench, never over-torqued, because over-torquing damages the internal gasket in the fitting and causes the very leak you were trying to prevent. If a braided line develops a slow drip at its loop later on, that line should be replaced rather than tightened further. Have your plumber shut off the supply valves before removing any line, which is one more reason the valves need to be reachable.

Older Faucets, 1/2 Inch NPT Lines and Adapters

Current 2-piece and 5-piece fast-fill faucets use 3/4 inch supply lines, which the team normally has on hand. Older Ella faucets used 1/2 inch NPT lines, which are not always available from Ella. Those are standard fittings you can pick up at a hardware store, or you can use a 3/4 inch line with a 3/4 inch to 1/2 inch reducer. The caution before shopping locally is that on some faucets the line is reverse-threaded at the faucet end, so send the team a photo of the actual line, including the end that connects to the faucet, before buying. The sizes and thread details are in Replacement Hot and Cold Faucet Supply Lines: Sizes, Threads and Where to Get Them.

If your original faucet model is no longer offered, the 5-Piece Fast Fill set is the replacement Ella supplies, and it brings the sizing question with it. The new set uses 3/4 inch supply lines, while older faucets usually have 1/2 inch lines. If the check valves under your tub have 1/2 inch connections, your plumber fits a 3/4 inch to 1/2 inch NPT adapter, which is a standard plumbing part. You do not have to replace everything: the existing spout and hand sprayer can stay in place while only the handles and valves are switched out, with the spout supply line adapted from 1/2 inch to 3/4 inch NPT. The full replacement path is in Replacing Your Walk-In Tub Faucet Set, Valves or Hand Mixer, and the layout of each set is in What Is a Fast-Fill Faucet on a Walk-In Tub?. For any of these requests, have your model, your serial number from the label behind the magnetic access panel next to the door, whether your faucet is the 2-piece or 5-piece, and a photo of the fitting ready for ellasbubbles.com/support or your Ella dealer or the team at (800) 480-6850.

Watch: Ellas Bubbles: Two Piece Fast-Fill Faucet Set Installation video with chapters and a full transcript.

Related Guides

• What Size Water Heater Do I Need for My Walk-in Tub?
• Why Does My Hot Water Run Out Before the Tub Is Full?
• What Is a Thermostatic Control Valve (TCV) on a Walk-In Tub?

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