Why Your Spa Might Be Draining Itself - And What to Do About It

Spa Draining Overnight? Here's What It Could Mean

It’s a common and frustrating issue: your pool or spa has just been resurfaced, everything looks perfect - and then the spa mysteriously drains when the pool equipment turns off. If you're constantly refilling the spa or noticing unexplained water loss, it's time to take a closer look.

This exact situation came up with a recent homeowner in Florida who had just renovated their pool. After filling up the spa, it drained almost entirely overnight when the pool system shut off. With no obvious cracks or leaks visible, they reached out to us for help determining the cause and solution.

WATCH: https://www.youtube.com/watch?v=3hMq-eejiv0

What Might Be Causing Your Spa to Drain When the Pump Is Off?

1. Failed or Missing Check Valve

One of the most common culprits behind this issue is a failed check valve—or the complete absence of one. A check valve is designed to stop water from backflowing out of the spa when the pump turns off. If this part fails or isn't installed, water from the spa may "transfer" back into the pool or plumbing system, especially due to gravity. Fret not - this isn’t a true leak.  Water’s simply moving from the spa to the pool.

2. An Undetected Leak

While a failed check valve can mimic a leak, it’s also possible that the spa’s structure or plumbing itself has a leak.  A professional pool and spa leak detection will find these issues.

3. Improvised or Temporary Plugging Solutions

In this case, the pool renovation company had attempted to (believe it or not) temporarily plug the spa’s main drain lines using foam and PVC inserts. These makeshift solutions failed to hold back the water. Unfortunately, we see odd improvised solutions like this too often.  Whatever the intent of the renovation company, the temporary fix failed, and a leak was uncovered.  

People Also Ask: Spa Leak FAQs

Why does my spa lose water when the pump is off?

This is often caused by water transferring out through failed valves or leaking plumbing. When the pump shuts down, water seeks the lowest point—typically draining back into the pool through the plumbing if a check valve isn’t holding.

Can it be a leak even if I don’t see water around the spa?

Yes. Most leaks in pools and spas do not leave visible puddles. Water often leaks out of a pool or spa without any obvious clues.

Will a check valve solve the problem?

If your spa is draining only when the system is off, a check valve is often the first thing to inspect. Replacing or installing a new valve is a cost-effective fix and can be done by a service company or a handy homeowner.

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What Our Leak Detection Service Offers

 We take every leak seriously, and we’ve written a full blog post explaining everything that’s included.  Here’s a high-level summary of our leak detection service:

Full Leak Inspection

Our licensed team will dive your pool and spa using scuba equipment to inspect drains, jets, skimmer lines, and any plumbing that may be contributing to the water loss. We also examine the entire structure, spillovers, water features, and any other areas that are a part of your system.

On-the-Spot Repairs (When Possible)

If we identify a leak that can be properly sealed with an underwater epoxy, we’ll take care of it during the original appointment—at no extra charge and without draining the pool or spa.  To understand when an epoxy repair is appropriate and when a construction-type repair is the right solution, read our blog, “When Is Epoxy Not The Right Choice For a Pool Leak Repair.”

Transparent Quoting for Advanced Repairs

If the issue requires a more involved repair, such as construction work, we’ll provide a clear quote. If booked within 30 days, you’ll receive a $200 credit toward the work.

Comprehensive Reporting

Our leak technician will not only call you, explaining all findings, but he’ll also email you a report explaining what he found. Even further, you’ll receive underwater videos and pictures showing all leaks and any areas of concern.

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An Example: Florida Homeowner Navigates Spa Drain Mystery

A homeowner in Longwood, Florida, contacted us after noticing that their spa would fully drain overnight when the pool system shut off. They had just resurfaced the pool, and temporary plugs weren't stopping the drainage.

We explained the likely causes—failed check valve, improper plumbing flow, or a true leak—and recommended a full inspection. They chose the full pool and spa package for peace of mind. We were able to schedule the appointment quickly, providing guidance to ensure the pool and spa were properly filled and clean for the technician’s arrival.

Our technician planned to test all spa components and plumbing lines, offering a same-day repair if possible and documentation for any larger issues.

How to Prepare for Your Leak Detection Appointment

To help us do our best work, we ask homeowners to:

• Fill the pool and spa to normal levels (typically halfway up the skimmer)
  
  
• Ensure water is clean and clear
  
  
• Unlock any gates or access points
  
  
• Let us know about any access limitations (e.g., tricky gates, unfinished construction)

To learn more about getting your pool ready for a comprehensive leak detection, read our blog post, “Is Your Pool Ready For The Best Leak Detection in Central Florida?”

Expert Pool Leak Repair in Orlando, FL

Don't let your freshly refinished spa go unused or worse, damaged because of a hidden leak. Whether it’s a simple fix or something deeper, our leak detection professionals are here to help you get answers and peace of mind.

Contact Aaron’s Leak Detection today to schedule your professional pool and spa leak inspection. We’re here to help you protect your investment and enjoy your water features worry-free.