Phoenix Pools: Heat Lies Fueling Summer Lung Mold?

By Franklin Everett Shaw

January 5, 2026

The air in Phoenix shimmers with heat, a dry, relentless sun beating down on everything. But beneath the surface of sparkling pools and manicured lawns, a hidden danger can lurk, especially in homes with older, less maintained swimming pool systems. It’s not the chlorine, but something far more insidious: fungal lung infections linked to malfunctioning pool heaters.

The connection might seem tenuous, but it’s a real threat, particularly for those with compromised immune systems or pre-existing respiratory conditions. We’re talking about Aspergillus, among other molds, finding a perfect breeding ground in the warm, stagnant water of a poorly maintained pool heater.

Here’s the problem: Pool heaters, especially older gas-fired models, can develop leaks or corrosion. This creates pockets of warm, damp air – an ideal incubator for mold spores. When the heater is turned on, these spores can be aerosolized and released into the air around the pool, ready to be inhaled.

This isn’t just theoretical. The CDC has documented outbreaks of Legionnaires’ disease linked to improperly maintained hot tubs and pools, and while Aspergillus infections are less common, the principle is the same: stagnant, warm water breeds trouble. Phoenix, with its high pool ownership and aging infrastructure, is particularly vulnerable.

So, what can you do to protect yourself and your family? Let’s break it down into actionable steps.

Step 1: Identifying Heater-Related Risks

The first step is to assess your pool heater. Don’t just assume it’s working perfectly. Look for these warning signs:

Visible Corrosion: Rust or corrosion on the heater’s exterior is a major red flag. It indicates that water is leaking and creating a damp environment inside.
Unusual Odors: A musty or moldy smell emanating from the heater is a clear sign of fungal growth. Don’t ignore it!
Inconsistent Heating: If your pool water isn’t heating evenly or the heater cycles on and off frequently, it could indicate a problem with the internal components, potentially creating stagnant water pockets.
Age of the Heater: Heaters older than 10 years are more likely to have internal corrosion and leaks. Consider replacing it with a newer, more efficient model.
Check the Exhaust Vent: Make sure the exhaust vent is clear of debris and properly ventilated. A blocked vent can cause backdrafting, leading to moisture buildup inside the heater.

Step 2: Proper Pool Maintenance Protocols for Arizona Residents

Arizona’s climate presents unique challenges for pool maintenance. The intense sun accelerates chlorine depletion, and the hard water can lead to scale buildup. Here’s a tailored maintenance plan:

Regular Water Testing: Test your pool water at least twice a week for pH, chlorine, alkalinity, and calcium hardness. Invest in a reliable test kit or take a sample to a local pool supply store. Leslie’s Pool Supplies, with multiple locations across Phoenix, offers free water testing.
Maintain Proper Chemical Balance: Keep your pH between 7.2 and 7.8, chlorine between 1 and 3 ppm, and alkalinity between 80 and 120 ppm. Use a pool calculator app to determine the correct amount of chemicals to add.
Shock Your Pool Regularly: Shocking your pool eliminates algae and bacteria. Do this weekly, especially during the hot summer months.
Clean Your Filter Regularly: A dirty filter reduces water circulation and can contribute to mold growth. Clean your filter according to the manufacturer’s instructions. Cartridge filters should be cleaned every 4-6 weeks, while sand filters should be backwashed weekly.
Inspect and Clean the Heater Annually: Hire a qualified pool technician to inspect and clean your pool heater annually. They can identify potential problems and ensure it’s operating safely and efficiently. Don’t skip this step!
Consider a Saltwater System: Saltwater systems produce chlorine naturally, reducing the need for harsh chemicals and minimizing the risk of chemical imbalances. They also tend to be gentler on pool equipment.
Winterize Properly: Even in Phoenix, temperatures can drop low enough to damage pool equipment. Properly winterize your pool by draining the pipes and adding antifreeze.

Step 3: Resources for Testing and Remediation

If you suspect mold contamination in your pool area, don’t panic. Here’s how to get it tested and remediated:

Mold Testing: Hire a certified mold inspector to take air and surface samples. Companies like Arizona Mold Experts and Phoenix Mold Remediation offer comprehensive testing services.
Professional Remediation: If mold is detected, hire a qualified mold remediation company to remove it safely and effectively. Look for companies that are certified by the Institute of Inspection, Cleaning and Restoration Certification (IICRC).
Heater Repair or Replacement: If your pool heater is the source of the mold, have it repaired or replaced by a licensed HVAC technician. Ensure the new heater is properly installed and vented.
Consult a Doctor: If you experience respiratory symptoms such as coughing, wheezing, or shortness of breath, consult a doctor immediately. Mention your concerns about potential mold exposure.

Common Mistakes and Pitfalls

Many Phoenix homeowners make common mistakes that exacerbate the risk of mold growth in their pool areas:

Neglecting Regular Maintenance: The biggest mistake is simply neglecting regular pool maintenance. Don’t wait until you see a problem to take action.
Improper Chemical Storage: Storing pool chemicals improperly can lead to spills and leaks, creating a damp environment that promotes mold growth. Store chemicals in a cool, dry, well-ventilated area, away from direct sunlight.
DIY Repairs: Attempting to repair your pool heater yourself without proper training can be dangerous and can worsen the problem. Always hire a qualified technician.
Ignoring Warning Signs: Ignoring warning signs such as unusual odors or inconsistent heating can allow mold to grow unchecked. Address any issues promptly.
Using Harsh Chemicals: Overusing harsh chemicals can damage pool equipment and create an imbalance in the water chemistry, making it more susceptible to mold growth. Follow the manufacturer’s instructions carefully.

Real-World Scenario

Consider the case of a family in Scottsdale, Arizona. They had an older gas-fired pool heater that had been in place for over 15 years. They noticed a musty smell around the pool area and their children started experiencing persistent coughs. A mold inspection revealed high levels of Aspergillus spores in the air and on the surface of the pool heater. The heater was found to have significant corrosion and leaks. The family had to undergo mold remediation and replace their pool heater. This scenario highlights the importance of regular maintenance and prompt action when warning signs appear.

Actionable Insights

Don’t wait for a problem to arise. Schedule an annual inspection of your pool heater by a qualified technician. Invest in a reliable water testing kit and test your pool water regularly. If you notice any unusual odors or respiratory symptoms, consult a professional immediately. By taking these proactive steps, you can protect yourself and your family from the hidden dangers of mold in your Phoenix pool. Remember, a sparkling pool should be a source of enjoyment, not a health hazard.