Pools are a staple of modern outdoor living, offering relaxation, recreation, and aesthetic appeal. But when the season ends, or maintenance demands draining the water, pool owners often ask: how long does it take for a pool to dry up? Whether it’s due to intentional draining, drought conditions, or leaks, understanding the drying process is essential for proper care and future use.
This article explores the key factors that determine drying time, the different types of pools, methods to accelerate or control the drying process, and potential risks involved. By the end, you’ll have a thorough understanding of how quickly—and under what conditions—a pool can completely dry up.
Understanding the Drying Process of a Pool
A pool isn’t just water in an empty shell; it’s a dynamic system that interacts with environmental, structural, and maintenance-related factors. Once the water is removed or exposure occurs, evaporation and residual moisture become key players in the drying timeline.
Factors Influencing Drying Time
Environmental Conditions
The climate and local weather play a substantial role in drying a pool. Key elements include:
- Temperature: Higher temperatures increase evaporation rates.
- Humidity: In dry climates, water evaporates more quickly than in humid ones.
- Wind: Air movement can significantly speed up evaporation by carrying away moisture particles.
Pond and Pool Surface Materials
Different materials retain moisture differently. Concrete and plaster retain water longer than vinyl or fiberglass pools.
Initial Water Depth
Naturally, the more water present initially, the longer it will take to dry completely. A deep in-ground pool will take longer than a shallow above-ground one.
Presence of Leaks or Residual Water
Even after draining, water may remain trapped in the plumbing system or beneath the pool structure, affecting drying time.
Pool Types and Their Drying Characteristics
Not all pools dry the same way or at the same speed. Understanding the differences can help pool owners better manage the drying process.
In-Ground Pools
In-ground pools, typically made of concrete, plaster, fiberglass, or vinyl liners, take longer to dry because of their depth and construction.
Concrete and Plaster Pools
These pools have porous surfaces, allowing them to absorb more water. Concrete can retain moisture in its matrix, and thus take longer to dry completely.
Fiberglass Pools
Less porous and smoother than plaster, fiberglass pools dry faster than their concrete counterparts. However, water may collect in corners or under fittings.
Vinyl-Lined Pools
Vinyl is non-porous, so drying time is quicker, but the flexibility of the liner can lead to water collection under folds or along the floor.
Above-Ground Pools
Above-ground pools, often made of steel or resin walls and a vinyl liner, have shallower depths and therefore dry more quickly. The metal or resin framework doesn’t retain moisture like concrete.
Portable and Temporary Pools
Smaller, inflatable pools made of PVC or polyethylene dry rapidly due to minimal water volume and low surface retention.
Stages of Pool Drying: What to Expect
The drying process can be segmented into distinct phases, each with unique characteristics and timeframes.
Surface Water Evaporation
This initial stage usually lasts between 24–72 hours, depending on weather conditions. Wind and sun help evaporate surface water, reducing visible moisture quickly.
Subsurface Moisture Loss
In plaster or concrete pools, water seeps into the material. Evaporation from within can extend the drying time up to a week or more. High temperatures shorten this phase.
Floor and Corner Accumulation
Pools designed with slopes or deep ends might retain water in lower sections. These areas may take several additional days to dry fully, especially if drainage is poor.
Internal Structures and Equipment
Skimmers, drains, and filtration systems may hold residue water, which evaporates more slowly due to reduced airflow. These components should be manually dried or flushed out for system integrity.
How Long Does It Take: Typical Drying Timelines
Timeframe for Above-Ground Pools
Shallow (18–30 inches): 2–5 days
Deeper (>36 inches): Up to a week depending on weather
Timeframe for In-Ground Pools
Cementitious surfaces: 1–2 weeks
Vinyl-lined: 5–10 days
Fiberglass: 4–8 days
Saltwater vs. Chlorinated Pools
Once drained, saltwater pools may dry faster as salt inhibits microbial growth. However, salt residue can be corrosive, so proper cleaning and flushing are essential.
Drying After Winterizing
Winterized in-ground pools with proper draining and air circulation may take a month to fully dry if left closed under a cover. Exposure to sun and air significantly reduces this.
Ways to Speed Up the Drying Process
If you’re preparing for repairs, resurfacing, or pool closure, accelerating drying is beneficial. Here are effective techniques:
Improve Airflow and Circulation
Opening the pool cover periodically or using fans increases airflow, encouraging moisture evaporation from the surface and corners.
Use of Pool Drying Products
Specialized coatings and moisture-absorbing products can be applied to the pool floor to help draw water out of surfaces faster.
Manual Water Removal
Use a wet/dry vacuum or a submersible pump to extract standing water and residual moisture from hard-to-reach areas.
Heat Application
Electric or gas heaters placed strategically around the pool can elevate air temperature and promote evaporation. However, this method is best for short-term use and should be done safely.
Potential Risks of Letting a Pool Dry Up
While drying a pool can be a necessary step, it comes with risks that pool owners must consider:
Structural Damage
Concrete pools may crack if they dry too quickly or without proper water balance. The pressure relief systems and groundwater levels around the pool can lead to “floating” or lifting of the shell if the pool is emptied too soon after filling.
Degradation of Surfaces
Exposure to the sun for an extended duration can bleach vinyl liners or cause plaster surfaces to become chalky or flake.
Mold and Bacterial Growth
If the drying is uneven or interrupted (e.g., by rain or humidity), trapped moisture in cracks or underneath pool fittings can stimulate mold growth, which may require intensive cleaning later.
Impact on Pool Equipment
Filtration systems, especially those left wet without use, may suffer from rust, clogging, or seal degradation if not properly shut down.
What to Do After a Pool Dries Up
Once the drying process is complete and favorable conditions are met, consider the following steps to preserve your pool and prepare for its next use:
Inspect the Pool Surface
Check for cracks, stains, or wear that could lead to leaks or poor water quality in the future.
Clean Residual Debris and Minerals
Salt deposits, calcium scaling, and sand should be removed to prevent surface damage and filter issues.
Apply Protective Coatings
For concrete pools, a temporary sealant or protective coating may help prevent weathering while the pool is dry.
Store Equipment Properly
Remove filters, pumps, and chemical dispensers if not in use, and store them indoors to reduce exposure to the elements.
Conclusion: A Balanced Approach to Pool Drying
Understanding how long it takes for a pool to dry up involves recognizing the interaction of environmental conditions, pool materials, construction type, and previous usage. There’s no one-size-fits-all answer, but with planning and proper execution, the drying process can be managed efficiently and safely.
Whether you’re preparing for maintenance, resurfacing, or winter storage, controlling the drying time of your pool ensures longevity and performance when the next swim season begins. Remember that careful monitoring and proactive management can make all the difference in preserving your investment and enjoying a clean, functional pool year after year.
By following this guide, pool owners can make informed decisions that align with their specific pool type, local climate, and seasonal needs. Proper drying is not just about waiting—it’s about optimizing your approach to maintain the beauty and functionality of your aquatic oasis.
How long does it take for a pool to dry up naturally?
A pool left to dry up naturally can take anywhere from a few weeks to several months, depending on various environmental factors. In hot, dry climates with high evaporation rates, a small pool might evaporate completely in a few weeks, while larger pools could take months. Variables such as temperature, humidity, wind, and overall exposure to sunlight play a crucial role in how quickly the water disappears.
In addition to climate conditions, the pool’s depth, surface area, and water volume significantly affect the drying timeline. Pools with deeper water or those located in shaded areas will take longer to dry, as shade reduces evaporation. Furthermore, if the pool is not completely sealed and groundwater or rainwater seeps in, this can prolong the drying process or even refill the pool partially.
Does draining a pool speed up the drying process?
Yes, actively draining a pool can significantly accelerate the drying process compared to natural evaporation. Using pumps or drainage systems allows for the rapid removal of water, with most pools being emptied within a few hours to a day, depending on the pump’s capacity and the pool’s size. Once drained, the residual moisture can be removed through fans, dehumidifiers, or simply through air exposure.
However, it’s important to consider structural concerns before draining a pool. In areas with a high water table, an empty pool can float or crack due to hydrostatic pressure from groundwater. Pool professionals often recommend draining a pool only when necessary and ensuring that proper drainage techniques and safety precautions are followed to avoid damage.
What environmental factors affect the time it takes for a pool to dry?
Several environmental factors influence the drying time of a pool, including temperature, humidity, wind speed, and sunlight exposure. High temperatures and direct sunlight increase evaporation rates, significantly reducing the time it takes for the water to dry. Conversely, cooler and more humid conditions slow down the evaporation process, making natural drying inefficient.
Wind also plays a notable role by increasing the moisture movement from the water surface into the surrounding air, thereby enhancing evaporation. Pools located in windy areas may dry faster than those in sheltered environments. Additionally, rain can prolong drying time by continually adding water to the pool surface, counteracting evaporation.
What happens to the surrounding area when a pool dries up?
When a pool dries up, especially if the process is long and natural, the surrounding ground may become saturated from water seepage or evaporation, impacting nearby vegetation and landscaping. Excess moisture can lead to issues such as soil erosion, mold growth, or the destabilization of nearby structures like decks, patios, or fencing.
Once the pool is fully dry, the immediate area might suffer from dust accumulation, particularly if there are exposed surfaces or old pool coatings flaking off. To mitigate these effects, it’s advisable to clean the pool area regularly and cover exposed parts of the structure during the drying phase. In the long run, proper land regrading and drainage management can help prevent water from pooling in adjacent regions after the pool has dried completely.
Can I cover the pool to reduce evaporation?
Yes, covering a pool is one of the most effective methods to reduce evaporation. Pool covers act as a barrier between the water and the air, minimizing moisture loss and helping to maintain water temperature. This is particularly useful for pools that are not in use but filled, as evaporation can account for significant water loss over time.
However, using a cover will slow or prevent natural drying if the intention is to let a pool dry up. In such cases, pool covers should be removed or avoided entirely. If evaporation is not desired—such as for conserving water—covers made of tightly woven material or thermal blankets are highly recommended for their efficiency in trapping moisture and reducing water loss by up to 90%.
How does pool type affect drying time?
The type of pool—whether it’s in-ground, above-ground, fiberglass, concrete, or vinyl-lined—can significantly influence drying time due to differences in depth, surface material, and structure. In-ground pools typically have more water and deeper basins, leading to longer drying times, especially if the drying process relies on natural evaporation.
Surface materials also affect how moisture is absorbed or released. For instance, plaster or concrete pools tend to absorb some amount of water, which can impact the drying process. Vinyl-lined pools may dry faster but can be more susceptible to damage if the liner dries out completely. Understanding the unique properties of each pool type allows for better planning when managing drying processes for renovation, cleanup, or removal.
Is it safe to leave a pool to dry on its own?
Leaving a pool to dry naturally is generally safe under certain conditions, particularly in warm and arid climates where evaporation is efficient. However, several safety and structural considerations must be taken into account. One primary concern is the pool water becoming stagnant over time, which can attract mosquitoes and create a potential breeding ground for pests, posing health risks.
Additionally, keeping a pool empty for an extended period without proper precautions may lead to damage. To address this, the pool should ideally be partially drained and inspected for structural integrity. Homeowners should also install barriers or fences around the pool to prevent accidents, especially if children or pets are present. For long-term dry storage, draining and cleaning the pool with professional guidance is often the safest and most effective option.