5 Possibilities for Pool Leaks When Pump Is Off

A pool is a great source of relaxation and enjoyment, but it requires regular maintenance to keep it in good condition. One troubling issue that pool owners often face is leaks. If you’ve called us before, you know that we ask you a series of questions. One of these questions is asking if your pool leaks when pump is off.

Understanding why your pool leaks when the pump is off is crucial for addressing the problem promptly and effectively. Here are five possibilities for why your pool leaks when the pump is off and steps you can take to resolve the issue. Most of these can be found using a simple pool dye test. If you need a pool dye needle, here’s the dye we use (click on the picture to take you to the Amazon page).

Pool Leaks When Pump is off?

First things first. Confirm your pool is leaking by doing a pool bucket test. If you have a leak, here’s our top 5 reasons why your pool leaks when pump is off.

1. Leaking Skimmer

The skimmer is a critical component of your pool’s circulation system, designed to remove debris from the water’s surface. However, it can develop leaks, especially when the pump is off and the water level is higher in the skimmer.

Leaking Skimmer Causes:

• Cracks in the Skimmer: Over time, the skimmer can develop cracks due to temperature changes, ground movement, or wear and tear.
• Loose Skimmer Gasket: The gasket that seals the skimmer to the pool wall can deteriorate or become loose, leading to leaks.

Leaking Skimmer Symptoms:

• The water level drops when the pump is off.
• Wet spots around the skimmer area.
• The deck is sinking around the skimmer area

Leaking Skimmer Solutions:

• Dye test the area: Squirt small amounts of dye into the cracks and all around the skimmer to see if a leak is pulling in the dye.
• Inspect for Cracks: Check the skimmer for any visible cracks and repair them with pool-safe epoxy.
• Replace the Gasket: If the gasket is worn or loose, replace it to ensure a proper seal.
• Epoxy the crack: Cracks in the skimmer throat or in the skimmer bucket may just need some epoxy and it will easily be fixed.
  • Click here for our favorite pool epoxy
• Replace the skimmer: You may need a pool company to break out the old skimmer and put a new one in.
• Inject the skimmer: Some skimmers can be injected with an expandable foam that can fill in all of the gaps and cracks from below and around the skimmer.

2. Pool Plumbing Leaks

Many of our customers call in thinking that since their pool is leaking when the pool is off then the leak isn’t in the pipes. Leaks in the pool’s plumbing system are common, even when the pump is off.

Pool Plumbing Leak Causes:

• Loose or Damaged Fittings: Fittings can loosen over time due to vibrations from the pump or physical damage.
• Cracked Pipes: Pipes can crack due to freeze-thaw cycles, ground movement, or improper installation.
  • Pipes crack from many reasons, sometimes pool companies forget to glue parts of their pvc together. Don’t be surprised if it’s something crazy that cause your pool pipes to break.

Pool Plumbing Leak Symptoms:

• The water level decreases when the pump is off or on.
• Puddles of water near the pump or plumbing lines.
  • Puddles of water can also pop up far away from the break.

Pool Plumbing Leak Solutions:

• Inspect Fittings: Check all visible fittings and tighten any that are loose. Replace any damaged fittings.
  • Using dye here will really help. Many times a fitting can look broken but if it isn’t pulling dye through the break it’s probably not leaking water.
• Check for Cracked Pipes: Inspect the plumbing lines for cracks and replace any damaged sections. A professional may need to pressure test the system to locate hidden leaks.
  • If you don’t want a professional to pressure test this, try turning off your pump for at least 24 hours and plugging your jets. Make sure the valve to the jets are turned off at the equipment.
  • If you stop losing water with your return lines plugged, then you have likely found the general location of the leak. (this can also work for skimmers and main drains).

3. Leaking Pool Shell

The pool shell itself can develop leaks, particularly if it has cracks or structural damage. This type of leak is often more noticeable and definitely the pool leaks when pump is off, as the water pressure is lower.

Leaking Pool Shell Causes:

• Cracks in the Concrete: Concrete pools can crack due to settling, temperature changes, or impact damage.
• Vinyl Liner Tears: Vinyl liners can tear due to age, improper installation, or sharp objects.

Leaking Pool Shell Symptoms:

• Visible cracks or tears in the pool shell or liner.
• Water loss is more pronounced when the pump is off.

Leaking Pool Shell Solutions:

• Repair Cracks: Use pool-safe epoxy or a concrete patch to repair cracks in the pool shell.
• Patch Vinyl Liners: Repair small tears in vinyl liners with a vinyl patch kit. For extensive damage, the liner may need to be replaced.

**4. Faulty Main Drain

The main drain at the bottom of the pool is another potential source of leaks, particularly when the pool leaks when pump is off and there is no suction to keep water from escaping.

Faulty Main Drain Causes:

• Loose or Damaged Drain Cover: The cover can become loose or damaged, allowing water to escape.
• Cracked Drain Line: The line connecting the main drain to the pump can crack, leading to leaks.

Faulty Main Drain Symptoms:

• Water loss when the pump is off.
• Wet spots around the main drain area.
• Bubbles in the pump.
  • Sometimes you’ll see these bubbles blowing out of the jets.

Faulty Main Drain Solutions:

• Inspect the Drain Cover: Ensure the drain cover is securely attached and not damaged. Replace it if necessary.
• Check the Drain Line: Inspect the line for cracks and repair or replace it as needed. This may require professional assistance.

5. Hydrostatic Relief Valve Issues

The hydrostatic relief valve is designed to prevent damage to the pool structure by relieving pressure from groundwater. If this valve malfunctions, it can cause pool leaks when pump is off.

Hydrostatic Relief Valve Issues Causes:

• Stuck or Damaged Valve: The valve can get stuck open or become damaged, allowing water to escape.
• Improper Installation: Incorrect installation can lead to valve failure and leaks.

Hydrostatic Relief Valve Issues Symptoms:

• Water loss when the pump is off.
• Wet spots around the pool
• You will likely see very little signs of this leak but the pool will often drain completely out if you turn everything off and stop filling it so be careful.
  • Once the pool drains to below the light or return jets, you could suspect this type of leak.

Hydrostatic Relief Valve Issues Solutions:

• Inspect the Valve: Check the hydrostatic relief valve for damage or debris that might be causing it to stick open. Clean or replace the valve if necessary.
• Professional Inspection: If the valve is improperly installed or severely damaged, consult a professional to ensure it is correctly repaired or replaced.
• https://www.troublefreepool.com/threads/hydrostatic-relief-valve-diagnosis-replacement.122669/

Preventive Measures and Maintenance Tips

To minimize the risk of leaks and extend the life of your pool, regular maintenance is essential. Here are some preventive measures:

1. Regular Inspections: Conduct routine inspections of your pool and equipment to catch potential issues early.
2. Maintain Proper Water Chemistry: Balanced water chemistry prevents damage to the pool surface and plumbing.
3. Winterization: If you live in a region with cold winters, ensure your pool is properly winterized to prevent freeze damage.
4. Professional Maintenance: Schedule regular maintenance with a professional pool technician to ensure all components are in good working order.

When to Call a Professional

While some pool leaks can be addressed with DIY methods, many others require professional assistance. If you cannot locate the source of the leak, if the leak is severe, or if you are uncomfortable performing the repairs, it’s best to call a professional. A pool specialist has the expertise and tools to diagnose and fix leaks efficiently, ensuring your pool stays in top condition.

Conclusion

Understanding why your pool leaks when the pump is off and taking the appropriate steps to fix it can save you from costly repairs and water loss. By identifying common causes such as leaking skimmers, plumbing leaks, cracked pool shells, faulty main drains, and hydrostatic relief valve issues, you can address leaks promptly and maintain your pool’s functionality. Regular maintenance and professional assistance will help keep your pool in excellent condition, providing years of enjoyment and relaxation. If in doubt, don’t hesitate to seek professional help to ensure your pool remains a refreshing oasis.