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Does the Fast Dual Drain Overwhelm Standard Household Drain Piping?

Updated September 2026

▶Glossary6
  1. Gravity Versus a Pump at the Junction
  2. What Happens Where the Tub Meets a 1.5 Inch House Line
  3. The House Line Sets the Pace
  4. Related Guides
  5. Related Videos
  6. Common Questions

No. Ella's Dual Drain Technology is purely gravity driven with no pump anywhere in the system, so nothing pushes water into your house piping. The water falls through the tub's 2 inch drains and the house line accepts it at whatever rate its size and condition allow, which is why a dual drain speeds up the tub side but cannot fix a slow house line. How Fast Does a Walk-In Tub Drain? Dual Drain Technology Explained covers the design in full.

Gravity Versus a Pump at the Junction

The concern in the question is really about pumped drains, and the video on this page draws that contrast. An installer who has fitted competing tubs explains that a standard house bathtub drain is 1.5 inches, that a 2 inch pipe carries about four times the volume of water of a 1.5 inch pipe, and that Ella tubs use two independent 2 inch drains: open the first and the tub drains at a fast pace, open the second and it goes faster still. The competing tub he compares it with starts with a single 1.5 inch drain and adds a drain button that runs a whirlpool-style pump to suck water out. Ella never does that. Because the system is gravity driven, the water is only ever moving under its own weight, and a pump or power failure can never leave you sitting in a full tub. The easy-turn drain handles also double as air vents, eliminating air pockets so the water flows out smoothly rather than in surges.

What Happens Where the Tub Meets a 1.5 Inch House Line

On dual drain models the two drains join under the tub into a single house connection, so there is one P trap and one reducing fitting, not two drain pipes. A 2 inch house main is recommended for the fastest emptying, but a standard T or Y fitting into a 1.5 inch house drain works. The plumber fits a 2 inch to 1.5 inch reducing coupling on the tub side of the P trap riser, or runs a 2 inch PVC 90 off the drain body and reduces ahead of the trap. A Y is preferred over a T because the water changes direction less. There is roughly 3 inches of clearance under the tub for 2 inch PVC, so the run can go to either side. Step-by-step layouts are in My House Drain Is 1.5 Inches. Will the 2 Inch Tub Drain Work?.

The House Line Sets the Pace

Actual drain time in your home depends on the tub's water capacity and on the condition and layout of your house drain. The fewer turns and the better the condition of your home's drainage, the faster the water leaves. That is why Ella asks for the house drain to be tested for free flow before the tub goes in, and why the drain must be trapped and vented to local code. The tub does not need a special vent of its own, since its drain handles vent the tub side. Under ideal house-drain conditions an average-size Ella tub drains in approximately 80 seconds, and field tests have recorded complete drainage in as little as 52 seconds. Larger tubs take longer, and connecting all four ports gives the fastest result. Where the drain lands on a slab is covered in Where Does the Drain Sit for a Slab Installation?.

Chapters in this video
  1. 0:00 Ella's Bubbles Dual Drain System The technician explains the advantages of Ella's Bubbles' two two-inch drain system for fast draining.
  2. 1:20 Competitor's Power Drain System The technician describes a competitor's power drain system, highlighting issues with water overflowing back into the tub.
  3. 3:20 Another Competitor's Drain System The technician discusses a competitor's standard waste gate overflow and another's single oversized drain.
  4. 3:55 Ella's Bubbles 4-Port Dual Drain The technician explains how Ella's Bubbles' 4-port dual drain system offers maximum versatility for plumbing installation.

Watch: Walk-In Tub With 4-Port Dual Drain System for Fast Draining: Voted Safest Tubs 2020 | Ellau2019s Bubbles with chapters and a full transcript.

Chapters in this video
  1. 0:00 Ella's Dual Drain Technology Ella's Bubbles walk-in tubs feature exclusive dual drain technology with oversized two-inch drains for efficient water removal.
  2. 0:17 How Dual Drains Work The video explains how Ella's dual two-inch drains connect to a house drain, offering maximum draining capacity.
  3. 0:47 Connecting to Your House Drain The video demonstrates connecting the tub's dual four-port t-type drains to a house drain on either the left or right side.
  4. 1:14 Dual Air Vents and Gravity Easy-turn drain handles double as air vents, eliminating air pockets and maximizing water outflow through a gravity-driven system.
Chapters in this video
  1. 0:00 Ella's Dual Drain Technology Ella's Bubbles walk-in tubs feature dual four-port two-inch drains for fast and efficient draining.
  2. 0:17 Oversized Two-Inch Drains Ella's walk-in tubs use two oversized two-inch drains, doubling air vent capacity to speed water out.
  3. 0:37 Connecting Your House Drain Customers can connect their house drain to all four ports for maximum draining capacity or seal unused ports.
  4. 1:01 Gravity Driven Drain System Ella's drain system is gravity-driven, so customers never worry about pump or power failure slowing the drain process.
Chapters in this video
  1. 0:00 Dual Drain Technology Overview The video introduces Ella's Bubbles dual 2-inch, four-port drain system and its connection to a house drain.
  2. 0:20 Live Drain Demonstration A live demonstration shows water flowing through the dual 2-inch, four-port drains.
  3. 0:39 Drain Setup Images Actual images display a drain setup before and after the installation of the dual drain system.
  4. 1:01 House Drain Connection Options The video explains recommended house drain connections and how installers determine the best setup.
  5. 1:27 Easy Turn Drain Handles The easy turn drain handles are shown, which also function as dual air vents to maximize water outflow.
  6. 1:40 Single Drain and Gravity Driven System Some tubs feature an oversized single drain with emergency pull chain, and the gravity-driven system is highlighted.

Common Questions

Does the Ella drain use a pump to push water out?
No. Every Ella tub drain is 2 inches and gravity driven, and there is no drain pump anywhere in the system. Water leaves under its own weight, so a power failure can never trap you in a full tub.
Will two 2 inch drains be too much for my 1.5 inch house drain?
The two drains join under the tub into one house connection, and a standard T or Y fitting steps down to a 1.5 inch line. Because the flow is gravity only, the house line simply takes water at its own rate. A 2 inch house main is recommended where possible for the fastest emptying.
Do I need a separate vent for the walk-in tub drain?
No. The easy-turn drain handles double as air vents on the tub side, which eliminates air pockets. Your house drain still needs to be trapped and vented to local code, which your licensed plumber handles.
Should each tub drain get its own house connection?
No. One P trap serving both tub drains is typical. Your plumber connects the two T-type ports nearest the house drain, or all four for maximum capacity, and caps the unused ports with the caps that ship with the tub.
Why does Ella prefer a Y fitting over a T fitting?
A Y adds fewer sharp turns, so the water changes direction less and drains better. Fewer elbows and a short run help the house line keep up with the tub.
What if my house drain is already slow?
Have an experienced plumber test the house drain for free flow before installation. A dual drain cannot fix a slow house line, and your actual drain time will depend on the condition and layout of your home's drainage.

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