Why is my Ella walk-in tub draining slower than it should?

An Ella walk-in tub drains by gravity through two 2-inch drains and typically empties in two minutes or less once it is connected to a proper 2-inch drain line, so a tub that takes noticeably longer is almost always being held back on the house side of the drain: a drain that is not fully open, only one of the two drains in use, an undersized or clogged branch line, poor venting, or a house drain that sits too high for gravity to work. How fast does a walk-in tub drain after a bath? explains what normal speed looks like. This page walks through the reasons a tub falls short of it, what you can check yourself at the tub, and what to hand to a licensed plumber.

What a Normal Drain Looks Like

Ella's own field test of the dual drain system finished in 52 seconds under Ella's conditions. The two minutes or less figure is the one Ella gives for a tub connected to a proper 2-inch drain line in a home, and it is the number to plan around. Nothing in the tub pumps the water out. Water flows straight down through the two 2-inch openings, so the speed comes from the size of the openings and the pull of gravity rather than from a motor that can wear out or lose power. That is why a slow drain is rarely a fault in the tub itself.

The hardware is simple and worth knowing before you troubleshoot:

• The drains are gravity-driven T-type four-port dual 2-inch drains.
• Each drain is operated independently by a large dial opener fitted with an extender for an easier grip and turn.
• The dials double as overflow protection and use a stainless steel cable with a lever to open or close each floor drain.
• The floor drain covers are height adjustable for optimum sealing and draining.
• The dual drain also works as a vent system, allowing fast air pocket relief and drainage.

That vent function is part of the speed. Air pockets are relieved rather than fighting the outflow, so a healthy tub keeps draining steadily to the end instead of slowing as the water level drops. A tub that starts quickly and then crawls for the last few inches is showing the opposite pattern, and that usually points at the venting and trap on the house side rather than at the tub.

Check These at the Tub First

1. Open both drains fully. Each drain has its own dial, and an installer who has fitted competing tubs describes the effect plainly: open the first drain and the tub empties at a fast pace, open the second and it goes faster still. If one dial is stiff or was only partly turned, a single drain is doing all the work.
2. Confirm the cable is lifting the cover. The dial moves a stainless steel cable with a lever that opens the floor drain. Turn each dial fully and watch the cover at the floor of the tub to confirm it actually rises.
3. Look at the cover height. The covers are height adjustable for optimum sealing and draining. If a cover was adjusted for a tight seal at installation, ask your plumber to confirm it still opens far enough to drain freely.
4. Count the connected ports. The drains are four-port units. Connecting two of the four ports is common, and connecting all four gives the fastest gravity flow. Your installer can tell you how many were tied in, and this is one change that can make a real difference on a tub that drains but drains slowly.

House-Side Causes for Your Plumber

Once the tub's own hardware checks out, the remaining causes belong to the home's plumbing, and How Fast Do Walk-In Tubs Drain and What Speeds It Up? lists what speeds a drain up. Read in reverse, the same list explains a slow one.

• An old, clogged or poorly vented house drain. This is the most frequent reason a new tub drains slowly. Ella asks for the house drain to be tested for free flow before the tub goes in, and the drain must be trapped and vented to local code. If that test was skipped, it is the first thing to have done now.
• An undersized branch line. A standard house bathtub drain is 1.5 inches, and a 2 inch pipe carries about four times the volume of water of a 1.5 inch pipe. The branch line the tub ties into should be 1 1/2 inches to 2 inches, and a 2 inch house main is recommended for the fastest emptying. A standard T or Y fitting into a 1.5 inch house drain does work, using a 2 inch to 1.5 inch reducing coupling on the tub side of the P trap riser, but it will not match a full 2 inch run.
• Too many turns. A Y fitting is preferred over a T because the water changes direction less, and the fewer turns in the run the faster the water leaves. There is roughly 3 inches of clearance under the tub for 2 inch PVC, so the run can go to either side.
• A drain that sits above the tub outlet. Because the system is gravity driven, the house drain has to sit below the tub. Draining into a washing machine box or any drain higher than the tub calls for a pump arrangement instead. A tub that was tied into a high drain without one will never drain at the rated speed.
• Not the sewer main. A tub on a 3-inch sewer line drains about as fast as one on a 4-inch line, because everything downstream of the 2-inch tub connection is already larger. Do not let a slow drain turn into a sewer upgrade.

What This Means for Your Bathroom

If the tub is already installed, a local licensed plumber is the right person to clear and test the house drain, confirm the trap and vent, and check the branch size and fittings. Ella does not send technicians. Before the plumber arrives, note how long a full drain takes, whether both dials open, whether the tub slows near the end, and whether the drain line rises anywhere between the tub and the stack. If you would like help understanding the tub's drain hardware, open a ticket at ellasbubbles.com/support or call (800) 480-6850 with your model and serial number. If a dial, cable or floor cover is confirmed faulty, the replacement part ships under your parts warranty and the plumber fits it.

If you are still planning the installation, the same list is your prevention checklist: have the house drain tested for free flow, run a 2 inch line with a Y fitting and as few turns as possible, keep the house drain below the tub outlet, and ask for all four ports to be connected. Fill time is a separate subject with its own numbers, covered in Drainage and Fill Time.

Related Guides

• How Do I Adjust the Drain Cable Tension When the Drain Will Not Open or Close Fully?
• My drain will not open or close: replacing the drain cable and adjusting drain height
• Drain Plug Will Not Open or Drains Slowly: Checking the Set Screw and the Stem

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