As a pool owner, you might wonder how often your pool needs to be drained. While the answer can vary, it largely depends on the pool’s construction type, water quality, maintenance practices, and repair needs. This article outlines when draining is necessary, what risks are involved, particularly with fiberglass pools, and how to maintain water quality effectively without resorting to frequent draining.
Key Summary: Pool Draining Essentials
| Topic | Key Insight | Best Practice |
| Fiberglass Pools | Highly vulnerable to damage if drained due to hydrostatic pressure | Avoid full draining unless absolutely necessary (repairs/resurfacing only) |
| When Draining is Needed | Repairs, repainting, or liner replacement | Always involve professionals |
| Water Quality Issues | Algae, cloudiness, chemical imbalance | Solve with water testing, balancing, and filtration rather than draining |
| Total Dissolved Solids (TDS) | Levels > 2,500 ppm make balancing harder | Opt for partial draining instead of full emptying |
| Seasonal Timing | Extreme heat or cold increases risk | Drain only in spring or early fall under dry conditions |
| Partial Draining | Safer and eco-conscious | Remove 6–12 inches to refresh chemistry or prep for winterization |
| Professional Oversight | DIY draining can cause cracks or floating pools | Hire pool experts to assess conditions and manage hydrostatic pressure |
| Long-Term Strategy | Prevention reduces need for draining | Regular water testing, filtration, debris removal, and annual inspections |
Fiberglass Pools and Draining Frequency
Why Draining Should Be Infrequent
Fiberglass pools are durable and low-maintenance, but they are especially vulnerable to damage when drained improperly. The pressure from groundwater, known as hydrostatic pressure, can cause the pool shell to lift or crack when empty. For this reason, draining a fiberglass pool is rarely recommended unless absolutely necessary, such as for structural repairs or resurfacing.
Situations That May Require Draining
Draining may be required for tasks like repairing cracks, repainting, or replacing the pool liner. However, this should always be done under professional supervision to prevent costly damage. Most water-related problems, including algae or cloudiness, can usually be resolved without emptying the pool.
Maintenance as the Best Prevention
Regular Testing and Balancing
Maintaining proper chemical levels is the key to avoiding premature draining. Consistently monitoring chlorine, pH, and stabilizer levels can prevent common issues such as algae growth and chemical imbalance. Balanced water also protects the pool’s finish and equipment from corrosion or scaling.
Monitoring Total Dissolved Solids (TDS)
TDS levels rise over time due to chemicals, dirt, and swimmer contaminants. When levels exceed 2500 ppm, water becomes more difficult to balance. In such cases, partial draining and refilling can help dilute the water without resorting to a full drain.
Proper Filtration and Debris Control
Filtration systems, particularly DE or high-capacity cartridge filters, are effective at maintaining clean water without draining. Manual debris removal through regular skimming and vacuuming further supports water clarity and helps limit chemical adjustments.
Avoiding Damage During Draining
Understanding Hydrostatic Pressure
Hydrostatic pressure is the upward force exerted by groundwater beneath the pool. When the pool is drained, this pressure can cause structural movement or cracking. To minimize the risk, professionals may use hydrostatic relief valves or only partially drain the pool, depending on soil and water table conditions.
Fiberglass-Specific Concerns
Draining a fiberglass pool should never be a DIY project. If not handled correctly, the shell can bulge, lift, or become permanently damaged. In-ground fiberglass pools, like those installed by professional landscape firms, require special attention to groundwater conditions and structural safeguards.
Timing Your Drain Properly
Best Seasons for Draining
If draining is required, spring or early fall is generally the best time. These seasons provide milder temperatures, reducing the risk of heat or freeze-related damage. Dry weather is also preferred to limit groundwater pressure around the pool.
Partial Draining as a Safer Alternative
In many cases, removing just 6 to 12 inches of water can be sufficient to improve water quality or prepare for winterization. Partial draining reduces hydrostatic risks and preserves water, making it a safer and more eco-conscious solution.
When to Involve Professionals
Risks of Improper Draining
Incorrect draining can lead to serious damage, particularly in areas with high water tables or clay-heavy soil. Cracked pool shells, floating structures, or even total pool failure can occur if hydrostatic forces are not managed.
The Importance of Expert Oversight
Hiring professionals to assess whether draining is necessary, and to manage the process safely, is highly recommended. From using the right equipment to understanding the ground conditions, pool contractors with fiberglass experience ensure the job is done correctly and safely.
Long-Term Water Management
Sustainable Pool Ownership
By focusing on preventive maintenance, most pool owners can avoid frequent draining altogether. Regular water testing, filter maintenance, and debris control all contribute to stable water chemistry, which supports the long-term health of the pool.
Occasional Professional Checkups
Even with strong maintenance habits, an annual or seasonal inspection by a qualified service provider can help spot early signs of damage, monitor water chemistry, and recommend partial draining if needed. This proactive approach ensures your pool remains both functional and beautiful.
Conclusion: Focus on Maintenance, Not Draining
Draining your pool should be an infrequent and carefully planned procedure, especially if you own a fiberglass model. Through proper water chemistry management, routine cleaning, and professional oversight, you can avoid the structural risks associated with draining while preserving water quality. Whether you’re managing seasonal changes or addressing an issue, always consult with an experienced pool service provider before draining. For homeowners who want peace of mind, professional pool installation and maintenance services like those offered by Guy Robert Landscape can help you enjoy your pool safely and worry-free for years to come.
