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The pre-installation water test: catch leaks before your walls are finished

Updated September 2026

The pre-installation water test is a required one hour check done before the walls are closed up: fill the tub, let it stand, run every electrical component, and inspect every connection. It is the single best insurance against opening finished walls later. Shipping vibration can loosen unions and air lines, and the water test catches all of it while everything is still easy to reach.

Watch: Installation Tips, Including the Fill Test

Our installation tips video walks through the whole sequence around the test: inspect for shipping damage, fill the tub with water outside the home to check for transit leaks, recheck all air, hydro, and electrical connections, level the tub so every foot carries weight, then fill the tub for an extended leak check and run the air, hydro, and electrical components for 20 minutes with a flashlight inspection of every union. The video suggests leaving the tub filled overnight if your schedule allows; the written procedure below is the required minimum.

The Required Test, Step by Step

  1. Place the tub on a flat, level surface. Confirm leveling first using our leveling guide, since an unlevel tub can leak at the door during the test.
  2. Wipe the door seal clean, then close the door.
  3. Tape the drains closed.
  4. Fill the tub to 3 inches above the highest jet. If your tub has no jets, fill to the bottom of the grab bar.
  5. Let the water stand for 30 minutes and inspect all around and underneath for any sign of water.
  6. Then run all electrical components on their rated 3-prong cords, plugged into separate outlets, for another 30 minutes, and inspect all unions and connections again while the pumps run.

Never start the pumps until the water covers all jets, since running a pump dry causes permanent damage that is not covered. The warranty activation form also has your installer confirm a watertight door seal after a 20 minute fill and watertight connections after running the hydro and air pumps for 20 minutes, so this test flows straight into activation.

Technician connecting braided water supply hoses to the fittings inside a walk-in tub access panel
Every union, supply connection, and air line is inspected through the access panels while the water stands and the pumps run.

If You Find a Drip at a Union

A leaking union at the pump or heater almost always means the union was over-tightened or the O-ring shifted. Disassemble the union, re-seat the O-ring, and reassemble it snugly. At the heater, also verify the heater threads match the pipe threads. This is a normal install-stage adjustment, not a defect, and it needs no service call. If water appears somewhere you cannot trace, our guide to finding the source of water under the tub walks through the usual suspects.

Check the Air Lines and Push Controls

On the Standard, Zen, and Flow platform, the push controls connect to an air hose that passes through the shell with a back nut. Tighten the push-control air-pipe connections and verify every push control actually works before finalizing the installation, since a loose air pipe is a known install-stage issue. More detail is in our push button air hose article.

Sealing a Push Control Button

If a push control button area ever weeps water, the video above shows the leak prevention procedure your installer can follow in a few minutes:

  1. Remove the button collar carefully with a flat edge, taking care not to scratch the tub surface.
  2. Remove the collar and the button.
  3. Place a thin bead of silicone caulk around the rubber gasket and smooth it to ensure complete coverage.
  4. Replace the button, then snap the collar back on.
  5. Smooth away excess silicone and clean the area with denatured alcohol.

Door Seal Checks

If the seal arrived slightly deformed from shipping, squeeze it with your fingertips and pull it gently away from the door frame to restore its shape, and clean it with rubbing alcohol. The door must close smoothly into a watertight seal. If it does not, re-check leveling before anything else, since leveling is the number one cause of door leaks. Keep the door open when the tub is not in use to preserve the gasket; our door seal care article covers the routine.

One More Leak Preventer: The Hand Shower

Never wall-mount the pull-out hand shower without the barrel extension hose kit. Without it, water drips through the deck insert hole and appears behind or under the tub. The kit's stainless barrel and 5 foot extension hose plug the deck hole: unscrew the mixer, thread the barrel onto the hose end, connect the extension hose to the barrel, seat the barrel in the deck hole, and connect the mixer to the extension hose. See hand shower hose orientation and mount base for photos of the parts.

Common Questions

Is the water test really required?
Yes. The one hour test is part of the published installation procedure, and the warranty activation form has your installer confirm the same fill and pump checks: a watertight door seal after a 20 minute fill and watertight connections after running the hydro and air pumps for 20 minutes. Shipping vibration can loosen unions and air lines, and skipping the test is the most common reason a leak is found only after the walls are finished.
Why fill 3 inches above the highest jet?
That level submerges every jet and puts water pressure on every joint in the hydro and air lines. A loose union or air fitting then shows itself during the 30 minute standing period and again during the 30 minutes the pumps run. If your tub has no jets, fill to the bottom of the grab bar instead.
Can I run the pumps to test them before the tub is full?
No. The water must cover all of the jets before any pump starts, because running a pump dry causes permanent damage that is not covered. Only the independent foot massage pump can run with just the footwell filled. Wait for the fill to reach 3 inches above the highest jet, then run the components on their rated 3-prong cords plugged into separate outlets.
A union drips when the pump runs. Is the tub defective?
Almost never. Shipping vibration or over-tightening shifts the O-ring, so take the union apart, re-seat the O-ring, and reassemble it snugly rather than forcing it tighter. At the heater, also confirm that the heater threads match the pipe threads. This is a normal install-stage adjustment that needs no service call.
Water appears around a push button. What now?
Follow the button sealing procedure shown in the video above. Remove the button collar carefully with a flat edge so the tub surface is not scratched, lift off the collar and the button, run a thin bead of silicone caulk around the rubber gasket and smooth it for complete coverage, then replace the button and snap the collar back on. Smooth away any excess silicone and clean the area with denatured alcohol.
The door leaks during the test. Do I need a new seal?
Check leveling first, because it is the number one cause of door leaks at install. Every leg must touch the floor with equal weight and the door must close smoothly into a watertight seal. If a level tub still leaks, squeeze and reshape the seal, clean it with rubbing alcohol, and re-seat it, then contact the team at ellasbubbles.com/support or (800) 480-6850 if the leak continues.
Should the test be done outside or in the bathroom?
Whenever possible, do a full fill outside or in the garage before the tub goes into the bathroom, which catches transit leaks while every fitting is easy to reach. Drain and dry the tub before moving it inside. Then repeat the fill and pump check in place after the connections are made and before the walls are closed.
Does the water test count toward the warranty activation checklist?
Yes. The installer initials the 20 minute door seal fill and the 20 minute hydro and air pump run on the warranty activation form, and those are the same checks the water test covers. Completing the test and the form together saves a step and documents that the installation was verified before the walls were finished.

Still need help? Open a ticket at ellasbubbles.com/support or call (800) 480-6850 and our technical support team will be glad to walk you or your installer through it.

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