How to Tell if Your Pool Leak Is Structural or Plumbing Related

Introduction

Owning a swimming pool comes with its fair share of joys — summer afternoons, family get-togethers, quiet evening swims — but it also comes with a few headaches. One of the most frustrating? A Pool Leak.

It usually starts subtly. You notice the water level dropping faster than usual. Maybe you think it’s just evaporation. But then, a few days later, the drop continues, and you start wondering, is something wrong? That’s when panic starts to set in.

The problem with a Pool Leak is that it can come from anywhere — a crack in the concrete, a loose fitting in the plumbing, or even a tiny tear in the liner. And telling whether it’s a structural pool leak or a plumbing pool leak isn’t always straightforward.

In this guide, we’ll break it all down in plain language. You’ll learn how to spot the signs, what tests you can do yourself, and when it’s time to call in the professionals for pool leak detection or pool repair.

By the end, you’ll know exactly how to tell if your Pool Leak is structural or plumbing-related — and, more importantly, how to stop it before it becomes an expensive disaster.

Understanding the Two Types of Pool Leaks

Not all leaks are created equal. Knowing which type you’re dealing with can save you hours of frustration and hundreds of dollars in unnecessary repairs.

Let’s start with the basics. There are two main types of Pool Leak issues: structural and plumbing.

A structural pool leak means there’s damage to the actual structure of the pool — think cracks in the shell, loose tiles, or worn-out caulking.

A plumbing pool leak, on the other hand, happens in the pipes that circulate water through your system — from the skimmers to the pump, filter, and returns.

Here’s the key difference:

• Structural leaks usually occur in the pool body (walls, floor, fittings).

• Plumbing leaks happen underground or in the equipment lines.

Both cause pool water loss, but their symptoms — and fixes — differ.

Signs of a Structural Pool Leak

You can think of a structural pool leak as the physical side of the problem. It’s something you can often see or feel. Here are the most common signs:

1. Visible Cracks in the Pool Shell

If you notice hairline fractures or larger gaps in the concrete or plaster, you may be looking at a pool structure crack. Even small cracks can let out a surprising amount of water over time.

A quick trick: mark the crack with waterproof tape, refill the pool, and check in 24 hours. If the water level drops below the mark, it’s very likely a structural pool leak.

2. Persistent Wet Spots Around the Pool

When water is seeping through cracks or joints, it often shows up as damp soil or soft spots around the pool deck. If the leak is structural, the wet area usually stays consistent — it doesn’t change when the pump turns on or off.

3. Tiles or Coping Coming Loose

Loose tiles or shifting coping stones can mean water is getting behind the pool shell, loosening adhesive and weakening the bond.

4. Structural Movement

If your pool deck is sinking or you notice uneven settling, it could be related to a slow, long-term Pool Leak undermining the soil beneath.

5. Bubbles or Air in Return Lines

This one can confuse people. Air in the system sometimes points to plumbing problems, but when it’s paired with visible cracks or movement in the pool walls, it might indicate a structural pool leak that’s letting air in.

Signs of a Plumbing Pool Leak

A plumbing pool leak can be trickier. These leaks hide underground, in pipes that you can’t see. But there are still patterns that help you narrow it down.

1. Water Loss Only When the Pump Runs

This is a big clue. If the water level only drops when your pump is operating, you’re likely dealing with a plumbing pool leak. The pressure in the pipes forces water out through cracks or loose joints.

2. Air Bubbles in Return Jets

When the pump pulls in air, it’s often from a suction-side leak — meaning somewhere before the pump.

If you see bubbles constantly blowing into the pool while the system runs, the leak might be in the suction line or skimmer connection.

3. Soggy or Wet Ground Near Equipment

Check the ground around your pump, filter, and heater. If it’s wet even on dry days, water could be escaping from fittings, valves, or buried return lines.

4. Inconsistent Water Loss

With plumbing issues, the amount of pool water loss often varies depending on pump operation. When the system is off, the leak may slow or stop completely.

5. Gurgling Sounds

You might hear gurgling or sucking noises near the skimmers. This can happen when air gets pulled into a cracked suction pipe — a classic sign of a plumbing pool leak.

Simple Leak Inspection You Can Do Yourself

Before calling a professional, you can run a few simple tests at home to confirm if you really have a Pool Leak — and what kind it might be.

1. The Bucket Test

This is the simplest leak inspection you can perform.

• Fill a bucket with pool water and place it on the pool’s top step.

• Mark the water level inside and outside the bucket.

• Wait 24 hours, ideally with the pump off.

If both levels drop evenly, it’s likely evaporation. If the pool level drops more than the bucket, you have a Pool Leak.

Now, repeat the test with the pump running. If the leak rate changes, it’s likely a plumbing-related issue. If it’s the same, it’s probably structural.

2. Dye Test

Get a bottle of pool dye or use food colouring.
Turn off the pump and let the water settle. Release a few drops of dye near suspected areas, such as cracks, drains, returns, or lights.

If the dye pulls inward, that’s where your Pool Leak is drawing water out.

3. Check the Equipment Pad

Inspect the pump, filter, and heater connections. Look for drips, rust, or mineral buildup. A wet equipment pad often means a plumbing pool leak.

4. Inspect Fittings and Lights

Leaks often appear around return fittings, skimmers, and underwater lights. These small openings can lose sealant over time, leading to subtle pool water loss.

Professional Pool Leak Detection Methods

If you’ve done the basics and still can’t find the issue, it’s time to bring in professionals. Modern pool leak detection technology is surprisingly precise — and can save you from unnecessary digging or resurfacing.

1. Pressure Testing

Technicians can isolate your plumbing lines and pressurize them with air. If the pressure drops, there’s a plumbing pool leak somewhere in the underground piping.

2. Acoustic Listening

Special hydrophones detect escaping air or water sounds through concrete. This is especially useful for finding a structural pool leak that isn’t visible.

3. Camera Inspection

Underwater cameras help locate leaks around fittings, drains, and lights without draining the pool.

4. Infrared Thermal Imaging

This technology detects subtle temperature differences between wet and dry soil — ideal for finding pool plumbing issues under concrete decks.

Each of these tests pinpoints the leak’s location, so you can repair only what’s necessary.

When to Call for Pool Repair

Knowing when to fix it yourself and when to call a professional is key.

If you’ve confirmed a small crack or worn-out sealant, you can try a temporary fix using epoxy or pool putty. But for larger structural cracks or plumbing leaks, it’s best to leave it to experts.

Professional pool repair companies have the tools to diagnose, seal, and reinforce your pool’s integrity. They’ll also help you determine whether the issue was caused by ground movement, faulty installation, or simple wear and tear.

And don’t wait too long. The longer a Pool Leak continues, the more expensive it becomes — not just in water bills, but also in damage to foundations and equipment.

The Hidden Costs of Ignoring a Pool Leak

A small Pool Leak might seem harmless at first, but the hidden costs pile up fast.

1. Increased Water Bills

Even a slow drip can waste hundreds of gallons a week. Over a summer, that’s money literally down the drain.

2. Structural Damage

Leaks erode soil around the pool shell, leading to settling, cracks, or even full structural shifts.

3. Equipment Strain

When your system keeps trying to refill water, pumps and filters work overtime. This shortens their lifespan and leads to more frequent pool repair.

4. Chemical Imbalance

A constant pool water loss messes up chemical balance, forcing you to use more chlorine and stabilizers to maintain safe swimming conditions.

In short, a Pool Leak never stays small. It grows — quietly — until it demands your attention.

Preventing Future Pool Leaks

Once you fix the current problem, it’s smart to prevent it from happening again. Prevention is part of good swimming pool maintenance, and it pays off over time.

1. Inspect Regularly

Set aside time every month to check for cracks, wet spots, and odd noises from the plumbing.

2. Keep Chemicals Balanced

Poor water chemistry can eat away at plaster and grout, eventually leading to a structural pool leak.

3. Maintain Equipment

Ensure the pump, filter, and valves are serviced annually. Faulty equipment causes unnecessary pressure and weakens seals.

4. Protect in Winter

For colder climates, like much of New England or the Northeast, improper winterisation can cause freezing damage that leads to cracks and pool plumbing issues.

5. Hire an Annual Leak Inspection

A yearly leak inspection by professionals is well worth the investment. It’s less expensive than major repairs and helps you identify small leaks early.

Realistic Scenario: A Leak That Looked Simple (But Wasn’t)

Let’s imagine a common situation.

You notice your pool’s water level drops half an inch every day. You check for cracks — nothing obvious. You run the bucket test, and it loses more water when the pump is on. That suggests a plumbing pool leak.

You call a technician. After a quick pressure test, they find the issue isn’t underground at all but in a return fitting behind a tile.

It’s a small, hidden Pool Leak — caused by a loose connection. It’s fixed in under an hour.

This happens all the time. Sometimes, what feels like a major issue turns out to be a small repair. And sometimes, it’s the other way around — a hairline pool structure crack ends up being the source of thousands of gallons lost.

That’s why consistent pool leak detection and smart swimming pool maintenance matter so much.

When to Replace vs. Repair

If your pool is over 15 years old, recurring leaks might be a symptom of deeper issues — worn-out plumbing lines or compromised structure.

In those cases, repeated patching may not be the most cost-effective option. A professional evaluation can tell you whether a resurfacing or plumbing replacement makes more sense long-term.

It’s never a fun decision, but ignoring it only delays the inevitable.

Key Takeaways

1. A Pool Leak can come from structural cracks or plumbing problems — knowing which helps you target repairs correctly.

2. A structural pool leak often shows visible damage, while a plumbing pool leak changes based on pump operation.

3. Simple tests, such as the bucket and dye test, can confirm if you have a leak, and you should call professionals.

4. Regular leak inspection and pool maintenance prevent minor problems from becoming costly disasters.

5. Fixing leaks quickly saves water, money, and protects your pool’s long-term structure.

Final Thought

A Pool Leak doesn’t always mean panic — it just means action. The quicker you identify where it’s coming from, the less damage you’ll face.

Sometimes, it’s as simple as tightening a fitting. At other times, it’s a sign of a bigger issue beneath the surface. However, with patience, routine checks, and professional assistance when needed, every pool can be restored to its perfect condition.

So next time your water level drops a little faster than expected, don’t ignore it. It’s your pool quietly asking for attention.

Frequently Asked Questions

1. How can I tell if my pool leak is structural or plumbing-related?
Run the bucket test. If water loss changes when the pump runs, it’s likely a plumbing pool leak. If it’s consistent, it’s probably structural.

2. How much water loss is normal for evaporation?
Typically, pools lose 1/8 to 1/4 inch per day to evaporation. Anything more could indicate a Pool Leak.

3. Can I fix a pool leak myself?
Minor cracks or seal leaks can be patched temporarily with epoxy or sealant. But for underground or structural issues, professional pool repair is best.

4. How long does professional leak detection take?
Most pool leak detection services take 1–3 hours, depending on pool size and complexity

5. How often should I check for leaks?
At least twice a year, and after any major weather changes. Regular swimming pool maintenance helps prevent long-term damage.

Related Helpful Resource

• Pool Resurfacing in Braintree MA

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