- When NOT to Drain Your Pool: Common Misconceptions
- Key Indicators: When to Drain a Pool is Necessary
- High Total Dissolved Solids (TDS)
- Sky-High Cyanuric Acid (CYA) Levels
- Extensive Staining, Scaling, or Mineral Build-up
- Major Repairs or Resurfacing
- Seasonal Draining for Specific Pool Types or Climates
- After a Major Contamination or Catastrophe
- Before and When to Drain a Pool: Essential Preparations
- How to Drain Your Pool Safely and Effectively
- Potential Risks of Draining Your Pool
- Conclusion
When to Drain a Pool: It’s a question many pool owners face, often accompanied by uncertainty and a hint of dread. While it might seem like a drastic measure, knowing when and how to properly empty your pool is an essential skill for long-term pool health and enjoyment. Draining a pool isn’t a routine task; in fact, for most homeowners, it’s a relatively rare occurrence. However, there are critical scenarios where a full drain is not only advisable but absolutely necessary to prevent costly damage, ensure water quality, and facilitate vital maintenance. This guide will walk you through the key indicators, essential preparations, and safe procedures for this significant pool operation.
When NOT to Drain Your Pool: Common Misconceptions
Before diving into when you should drain, let’s clarify when it’s usually unnecessary. Many pool problems can be remedied without emptying thousands of gallons of water.
Slightly Green or Cloudy Water: Minor algae blooms or cloudy water due to improper chemical balance are almost always treatable with shocking, filtration, and correct chemical adjustments. A drain is overkill and wasteful in these instances.
Minor Staining: Small, isolated stains on your pool’s surface can often be treated with targeted stain removers or by brushing and chemical balancing.
Difficulty Balancing Chemicals: Persistent chemical imbalances (such as high pH or low chlorine) can usually be corrected with diligent testing and the addition of appropriate chemicals, often over several days or weeks. Only extreme, unmanageable imbalances might nudge you towards a drain.
General “Age” of Water: Contrary to popular belief, pool water doesn’t inherently go “bad” just because it’s been in the pool for a long time. It’s the accumulation of dissolved solids and persistent chemical issues that dictate its usability.
Unless these issues are severe, pervasive, and resistant to all conventional treatment, a partial drain-and-refill (dilution) is usually a more appropriate first step than a complete emptying.
Key Indicators: When to Drain a Pool is Necessary
There are specific, undeniable reasons why a complete pool drain becomes the most logical and effective solution. These situations represent a point where traditional chemical treatments or minor interventions are no longer sufficient.
High Total Dissolved Solids (TDS)
One of the most common and compelling reasons to drain your pool is excessively high Total Dissolved Solids (TDS). TDS refers to all the inorganic and organic substances dissolved in your pool water, including minerals from source water, salts from chemicals, sunscreen, body oils, dirt, and dust. Over time, these accumulate. When TDS levels exceed 1,500-2,000 ppm (parts per million), you might notice:
Water that looks dull or hazy, even when chemically balanced.
Reduced sanitizer effectiveness, leading to more frequent shocking.
Difficulty maintaining proper pH and alkalinity.
Increased potential for scaling and staining.
The only way to effectively reduce very high TDS is by removing the old water and replacing it with fresh water.
Sky-High Cyanuric Acid (CYA) Levels
Cyanuric Acid (CYA), also known as chlorine stabilizer, protects chlorine from degradation by UV rays. While essential, too much CYA (typically above 80-100 ppm) can actually “lock up” your chlorine, rendering it ineffective, even when your chlorine levels test normally. This leads to persistent algae problems and bacterial growth, despite adequate chlorine readings. Like TDS, the only way to significantly lower CYA levels is through dilution or by draining and refilling the pool.
Extensive Staining, Scaling, or Mineral Build-up
If your pool surfaces are covered in widespread, deep-seated stains, heavy mineral deposits (calcium scale), or severe algae infestations that resist scrubbing and chemical treatments, draining provides the perfect opportunity for an intensive clean. When the pool is empty, you can use specialized acidic cleaners or pressure washing methods safely to restore the pool’s finish.
Major Repairs or Resurfacing
This is arguably the most obvious reason. If your pool requires significant repairs to its shell, plumbing, or major equipment that necessitates access beneath the water line, or if you’re planning to resurface (e.g., replaster, replace a liner, paint), the pool must be completely empty. Trying to work with water in the pool is impractical and can compromise the repair quality.
Seasonal Draining for Specific Pool Types or Climates
While most inground pools are not fully drained for winterization, some above-ground pools, especially those with soft-sided liners, may need to be drained and stored for the colder months. Additionally, homeowners in areas with extreme freeze-thaw cycles who cannot adequately winterize their pool water might choose to drain to prevent ice damage. However, always consult with a local pool professional before draining for winter.
After a Major Contamination or Catastrophe
If your pool has been severely contaminated by an uncontrolled chemical spill, sewage backup, or a natural disaster (like a flood that overwhelms your filtration system), draining and sanitizing the entire pool is the safest course of action to ensure public health and safety.
Before and When to Drain a Pool: Essential Preparations
Draining a pool isn’t as simple as pulling a plug. Careful planning is crucial to prevent damage to your pool or property.
1. Check Local Ordinances: Many municipalities have regulations about where you can discharge pool water due to the chemicals it contains. Contact your local water department or environmental agency to understand rules regarding storm drains, sanitary sewers, or private property discharge.
2. Monitor the Water Table: Crucially, if you have an inground fiberglass or vinyl liner pool, or live in an area with a high water table (especially after heavy rain), never drain your pool completely. The hydrostatic pressure from groundwater can cause the empty shell to “pop” out of the ground or severely damage a vinyl liner, leading to catastrophic and expensive repairs. Consult a professional if you’re unsure.
3. Gather Equipment: You’ll need a powerful submersible pump (often rentable), a long discharge hose, and potentially a shop vacuum for the last few inches of water.
4. Plan the Discharge: Determine the path the water will take. Ensure it flows away from your home’s foundation, landscaping, and neighboring properties.
How to Drain Your Pool Safely and Effectively
Once you’ve determined that when to drain a pool is now, follow these steps meticulously:
1. Turn Off All Equipment: Disconnect power to your pump, filter, heater, cleaner, and any other pool equipment to prevent damage when the water level drops. If you have a chlorinator, empty it and rinse it thoroughly.
2. Set Up the Pump: Place the submersible pump at the deepest part of your pool. Attach the discharge hose and route it to your approved discharge location. Secure the hose to prevent it from moving during the process.
3. Begin Draining: Start the pump. It can take anywhere from 8 to 24 hours or more to drain a typical residential pool, depending on the pump’s capacity and the pool’s size.
4. Monitor the Process: Keep an eye on the water level. As it drops, you can start cleaning the pool walls if needed.
5. Clean the Empty Pool: Once empty, clean the surfaces thoroughly. Remove debris, scrub away stains, perform any necessary repairs, or prepare for resurfacing.
6. Refill Slowly: When refilling, monitor the water level carefully. This is especially important for vinyl liner pools, as filling too quickly can cause creases. As the water level rises, re-install any removed fixtures (like main drain covers) and slowly bring your chemicals back into balance.
Potential Risks of Draining Your Pool
Despite its necessity in some cases, draining a pool carries risks:
Pool “Popping Out”: As mentioned, hydrostatic pressure can lift an empty shell out of the ground.
Liner Damage: Vinyl liners can shrink, crack, or become brittle when exposed to air and direct sunlight. They often don’t relax back into place perfectly, leading to wrinkles.
Cracking: Plaster or concrete surfaces can crack due to drying out too quickly, especially in hot, sunny weather.
Equipment Damage: Running pumps or heaters without water will cause irreversible damage.
Conclusion
Knowing when to drain a pool is a critical aspect of responsible pool ownership. It’s not a decision to be taken lightly, but rather a carefully considered solution for specific, unresolvable problems like high TDS or CYA, severe staining, or major structural repairs. Always prioritize safety, understand the potential risks, and check local regulations before initiating a full drain. When in doubt, consulting a qualified pool professional can provide invaluable guidance and ensure the longevity and beauty of your swimming oasis.
