How to Clean a Hot Tub That Has Been Sitting




How to Clean a Hot Tub That Has Been Sitting

Hot tubs offer a luxurious escape from the daily grind, providing relaxation, therapeutic benefits, and a touch of indulgence right in our backyards. However, like any other luxury, they come with their own set of responsibilities.

Regular maintenance is crucial to ensure that the water remains clean, safe, and inviting. But what happens when life gets in the way, and our cherished hot tub sits neglected for days, weeks, or even longer? So how to clean a hot tub that has been sitting?

The risks are more than just murky water. Leaving a hot tub sitting for extended periods can lead to the growth of harmful bacteria, algae, and biofilm, turning your relaxation haven into a potential health hazard.

This guide aims to walk you through the comprehensive steps of how to clean a hot tub that has been sitting idle, ensuring it’s safe, clean, and ready for your next soak.

Hot Tub Cleaning Guide

Understanding the Problem:

A hot tub is more than just a container of water; it’s a complex system where water circulates, gets heated, and is treated to provide a soothing experience. However, when left stagnant, this system can quickly become a breeding ground for various microorganisms.

How Spa Water Deteriorates Over Time:

Water, when left untreated, doesn’t stay the same. If you keep your hot tub covered, you will have clean water for around 14 days. Beyond this period, the lack of circulation, filtration, and sanitization allows for the rapid multiplication of microorganisms. The water begins to lose its clarity, often taking on a cloudy or greenish hue.

The Growth of Algae, Bacteria, and Biofilm:

Algae and bacteria are opportunistic. In the absence of regular sanitization, they can quickly colonize a hot tub. Algae, even without direct light, can proliferate under a dark spa cover, leading to slippery surfaces and green-tinted water. Bacteria, on the other hand, can pose direct health risks, causing skin irritations or more severe infections.

Perhaps the most insidious of all is the formation of biofilm. Biofilm is a slimy layer formed by bacterial colonies. It adheres to the surfaces of the hot tub, especially in the plumbing where it’s harder to clean. This biofilm acts as a protective shield for bacteria, making them resistant to regular sanitization methods.

Once you understand what the issues are, you can take steps to deal with them. With this knowledge, we can delve into the solutions to bring your hot tub back to its pristine condition.

Steps to Tackle Your Dirty Hot Tub

Initial Assessment: Test the Filter System

Before diving into the cleaning process, it’s essential to ensure that the core components of your hot tub are functioning correctly. The filter system, in particular, plays a pivotal role in maintaining water clarity and cleanliness.

The Importance of the Spa Pump and Filter:

The spa pump circulates the water, while the filter captures and removes contaminants. Together, they form the backbone of your hot tub’s sanitation system. If either is malfunctioning, even the cleanest water can quickly become a breeding ground for bacteria.

Steps to Check the Spa Pump and Filter:

1.Check Water LevelEnsure water covers the spa filter. Add water if necessary.
2.Power UpTurn on power at the circuit breaker.
3.Inspect EquipmentCheck over the spa and equipment for any damage
4.Reset OutletsReset any tripped GFCI outlets.
5.Valve InspectionEnsure all valves are open (both before and after the pump).
6.Leak DetectionLook for signs of leaking water under the spa.
7.Test Pump functionUsing the spa control, run the pump to check it’s functional

Identifying and Addressing Potential Leaks:

Leaks can be a significant issue, leading to water wastage and potential damage to the hot tub’s structure and equipment. If you notice any wet spots or pooling water under the spa during your inspection, it’s crucial to address these leaks before proceeding with the cleaning process.

Tips for a Successful Assessment:

  • Always ensure the power is turned off before physically handling any electrical components.
  • If your spa has both a circulation pump and a jet pump, test both to ensure they’re operational.
  • Consider replacing the filter cartridge if it’s old or visibly dirty. A clean filter will significantly improve water clarity and cleanliness.

By ensuring the filter system is in top condition, you’re laying the foundation for a successful cleaning and rejuvenation of your hot tub.

Draining and Cleaning the Hot Tub

Once you’ve ensured the filter system is operational, the next step is a thorough draining and cleaning of the hot tub. This process removes stagnant water, accumulated contaminants, and sets the stage for a fresh start.

Why Draining is Essential:

Stagnant water in a hot tub that has been sitting for an extended period is a cocktail of contaminants. From algae and bacteria to biofilm and other debris, the best way to ensure a clean start is by completely draining this water.

Steps to Drain the Spa or Hot Tub:

  • Locate the Drainage Port: Most hot tubs come equipped with a drainage port or hose. This can often be found at the base of the cabinet or as a hose connection at the tub’s lowest point.
  • Drain by Gravity: If your spa doesn’t have a pump-assisted drainage system, simply pull out the hose or connect a hose to the drainage port and let the water flow out using gravity.
  • Use a Submersible Pump: For faster draining, or if your spa doesn’t have a dedicated drainage system, a submersible pump can be used to remove the water. Ensure the power to the spa is turned off before using a pump.
  • Clean as You Drain: As the water level drops, use a garden hose to spray off the spa’s surfaces. This helps in dislodging and removing any slimy residues. For stubborn areas, consider using a soft scrub brush. Be cautious not to spray water on the spa’s electrical components.

Cleaning the Spa Surfaces and Jets:

  • Surface Cleaning: With the spa emptied, use a spa-specific cleaner or a mild detergent to scrub the surfaces. This removes any lingering contaminants and prepares the tub for refilling.
  • Jet Cleaning: The jets can harbor biofilm and other residues. Spray water directly into the jets to help dislodge any buildup. For a deeper clean, consider using jet cleaning solutions available in the market.

Tips for a Successful Draining and Cleaning:

  • Always ensure the spa’s power is turned off during the draining process to avoid any electrical hazards.
  • Avoid using abrasive scrubbers or harsh chemicals that might damage the spa’s surface or leave residues.
  • If you notice any damage during cleaning, it’s a good time to address it before refilling the tub.

By thoroughly draining and cleaning the hot tub, you’re not only removing contaminants but also ensuring that the fresh water you add next remains clean for a longer period.

Everything You Need For Healthy Water

Final Drain, Refill, and Chemical Treatment

After cleaning the inside of the hot tub, give it a final rinse with a hose and a final drain. Then you can refill, and give a chemical treatment to ensure your hot tub is ready for use. This phase ensures that all contaminants, both visible and hidden, are removed, and the water is balanced and sanitized.

Refilling the Hot Tub:

  • Use Fresh Water: Refill your spa using a hose. Consider using a hose filter if your tap water has high mineral content.
  • Check Water Level: Ensure the water level is appropriate. Follow the level lines inside the hot tub or follow the manufacturers guidelines.

Chemical Treatment:

  • Test the Water: Before adding any chemicals, test the water using a spa test kit or test strips. Check for pH, alkalinity, and calcium hardness levels.
  • Balance the Water: Based on the test results, add adjustment chemicals if needed. This might include pH increasers or decreasers, alkalinity boosters, and calcium hardness increasers.
  • Sanitize: Add a sanitizer, such as bromine or chlorine, to kill any remaining bacteria. If you use bromine tabs, consider adding a bromine booster.
  • Shock the Hot Tub: Use a spa shock treatment, following label instructions. This oxidizes contaminants, ensuring clear and sanitized water.

Tips for a Successful Refill and Treatment:

  • Always add chemicals one at a time, allowing a few minutes between each addition. This prevents chemical reactions and ensures each product works effectively.
  • After adding chemicals, run the spa’s circulation system for at least 30 minutes to distribute them evenly.
  • Always store chemicals in a cool, dry place, away from direct sunlight and out of reach of children.

By following these steps, you ensure that your hot tub is not only clean but also chemically balanced, providing a safe and enjoyable soaking experience.

Filter Maintenance

The filter plays a pivotal role in maintaining the clarity and cleanliness of your hot tub water. It captures and removes fine particles, debris, and contaminants, ensuring a pleasant soaking experience. Regular maintenance and timely replacement of the filter cartridge are crucial for optimal performance.

Importance of the Hot Tub Filter:

The filter acts as the primary defense against contaminants. As water circulates through the filter, impurities get trapped, preventing them from re-entering the hot tub. A well-maintained filter ensures efficient water circulation, reduces strain on the pump, and keeps the water clear.

Steps for Filter Maintenance:

Inspect Regularly: Check the filter cartridge for visible signs of wear, tear, or clogging. A damaged or overly dirty filter won’t function efficiently.

Clean the Filter:

Depending on usage, clean the filter every 2-4 weeks. Here’s how:

  • Rinse: Use a garden hose to spray off loose debris from the filter pleats.
  • Soak: For a deeper clean, soak the filter overnight in a filter-cleaning solution.
  • Rinse Again: After soaking, rinse the filter thoroughly to remove any cleaning solution residues.
  • Dry: Let the filter totally dry, and then you can reinstall it. If any bacteria survive the previous cleaning, this will finish them off.

Replace When Needed:

Over time, the filter’s efficiency decreases, even with regular cleaning. You can clean off your filter up to 12 times before it’s recommended that you replace it. Or around every 12 months.

Choosing the Right Replacement Filter:

When it’s time to replace the filter, ensure you choose the correct size and type for your hot tub model. Using the wrong filter can reduce efficiency and potentially damage the pump or plumbing.

Tips for Effective Filter Maintenance:

Always turn off the hot tub and disconnect power before removing or installing the filter.
Avoid using household cleaners or bleach on the filter, as they can damage the filter material and leave residues.
Keep a spare filter on hand. This allows you to swap out filters quickly, ensuring minimal downtime for your hot tub.

By giving your filter the attention it deserves, you’re ensuring a clear, clean, and safe hot tub experience, prolonging the life of your spa and its components.


A hot tub is more than just a luxury; it’s a commitment to relaxation, health, and well-being. However, like all commitments, it requires attention and care. Whether your hot tub has been sitting for a few weeks or several months, rejuvenating it is not just about aesthetics but also about ensuring a safe and healthy environment for you and your loved ones.

Throughout this guide, we’ve walked you through a comprehensive process, from understanding the issues with stagnant water to filter maintenance. Each step is crucial in ensuring that your hot tub remains a source of joy and relaxation, rather than a breeding ground for contaminants.

In the end, regular maintenance is the key. By following the steps and tips provided, not only will you extend the lifespan of your hot tub, but you’ll also ensure that every soak is as refreshing and safe as it should be. So, here’s to many more hours of relaxation, rejuvenation, and enjoyment in your freshly cleaned and well-maintained hot tub.

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