When an in-ground swimming pool develops a leak, the water doesn’t simply disappear. It escapes into the surrounding environment—sometimes slowly and quietly, sometimes dramatically—and can have serious consequences if left unaddressed. In this comprehensive guide, we’ll answer the question: Where does the water go when a swimming pool leaks?
We’ll explore the main pathways of water loss, how it travels through soil and structures, and the environmental and structural consequences that follow. If you’re noticing signs of a pool leak or want to understand the potential implications, this guide is for you.
Common Leak Pathways in In-Ground Pools
1. Underground Plumbing Leaks
In-ground pools rely on a network of underground pipes to circulate water. These include suction lines, return lines, and cleaner lines. Leaks here occur when joints crack, pipes rupture, or connections fail. The leaked water seeps into the trench where the pipes were laid, typically filled with sand or gravel and follows the path of least resistance through the soil. This can create soft spots in your yard, uneven grass growth, or visible pooling. Over time, the moving water erodes the surrounding soil, creating voids that may destabilize the ground above.
2. Structural Shell Leaks
Concrete, fiberglass, or vinyl-lined pool shells can develop leaks through cracks, tears, or faulty construction. Water leaking from the shell seeps directly into the surrounding soil. In gunite or shotcrete pools, structural cracks can form in the walls or floor due to soil movement or poor construction. In vinyl liner pools, small tears can allow water to migrate behind the liner, causing corrosion of steel walls or loss of backfill.
Shell leaks typically result in soil saturation directly adjacent to the pool. As the soil becomes waterlogged, it loses stability, potentially causing the pool shell to settle or shift. In some cases, the leak rate slows when the surrounding soil becomes fully saturated, appearing as though the leak has “stopped”—but this is only temporary.
3. Fitting and Fixture Leaks
Penetrations in the pool shell, such as skimmers, return jets, light niches, and main drains, are sealed during the construction process. Over time, these seals can degrade.
Skimmer leaks are among the most common and often occur where the plastic skimmer body meets the concrete shell. Pool light leaks, typically located in the conduit line behind the niche, can allow water to travel away from the pool shell toward the electrical junction box or the surrounding soil.
As with shell leaks, water that escapes through fittings saturates the immediate soil and may travel along pipe trenches or structural voids. In time, this can lead to shifting decks, cracked tiles, or sinking coping stones.
4. Equipment Pad Leaks
Leaks in the pump, filter, heater, or plumbing joints near the equipment pad don’t enter the pool’s shell or plumbing, but they still waste water and can cause erosion. Water leaking at the equipment pad can saturate the ground, corrode infrastructure, or affect adjacent structures.
How Escaping Pool Water Moves Through the Environment
Immediate Soil Saturation
Once water escapes from a leak, it immediately saturates the surrounding soil. The characteristics of this movement depend on the type of soil: sandy soils allow for quicker percolation, while clay-rich soils retain water, spreading moisture horizontally. Over time, soil erosion can occur, particularly in areas where backfill was not appropriately compacted during pool construction.
As the soil becomes waterlogged, its capacity to support structures diminishes. The pool shell may settle unevenly, and deck slabs can crack as the base material erodes. The result is not just aesthetic damage but potential safety hazards.
Downward Percolation to Groundwater
With gravity’s pull, leaked water continues to travel downward through the soil profile, a process known as percolation. Eventually, it reaches the water table and becomes part of the natural groundwater supply. Along the way, water can interact with various soil layers, dissolve minerals, and, in some cases, carry pool chemicals with it.
This migration contributes to the local hydrology and, although diluted, may impact water quality, particularly in regions with shallow aquifers. In rare cases, particularly in areas with karst or limestone geology, the continuous flow of pool water can dissolve underground rock, contributing to cavity formation and, potentially, the development of sinkholes.
Lateral Migration and Surface Emergence
Water doesn’t always flow directly downward. If it encounters an impermeable layer, such as clay or a barrier, it may move sideways. This lateral movement can result in water surfacing at unexpected locations, such as a slope downhill from the pool or along the base of a retaining wall.
In plumbing trenches or near fittings, water may follow the path of least resistance—often the conduit or pipe trench—to emerge far from the source of the leak. This makes detection difficult and underscores the value of professional leak-detection tools.
Structural and Environmental Impacts of Escaped Water
Erosion and Soil Displacement
Water movement through soil disrupts its natural structure. As water flows, it can carry fine soil particles with it, resulting in gradual erosion. This erosion leads to voids, undermining the support beneath pool decks, patios, and the pool shell itself. The most common consequence is cracking or sinking in concrete decks and shifting of coping stones or tiles.
In extreme cases, persistent leaks can lead to ground collapse or small-scale sinkholes, particularly in unstable soil conditions or when poor construction backfill is used. These voids not only endanger structures but pose a safety risk to people walking near the pool.
Structural Stress to Pool and Surroundings
The structural integrity of a pool relies on uniform support from the surrounding soil. As water escapes and erodes that soil, it can create uneven pressures on the pool shell. This may lead to cracking, bulging in fiberglass shells, or deformation in vinyl liners. Concrete pools may develop deep structural fractures that allow even more water loss.
Beyond the pool, adjacent structures, such as patios, walkways, outdoor kitchens, and nearby homes, can also suffer damage. If leaked water migrates toward a house foundation, it can cause slab settling, wall cracks, and mold growth in basements or crawl spaces.
Landscape and Yard Damage
Overwatering from a pool leak can saturate and ruin landscaping. You might see unusually lush grass or, conversely, dead patches due to chlorine or salt damage. Soil erosion may also cause plant beds to shift or pavers to settle unevenly. Insects, fungi, and mold can thrive in perpetually wet conditions, further damaging your yard’s aesthetics and usability.
Environmental and Regulatory Concerns
Though most pool leaks involve manageable volumes, long-term leaks can contribute to localized environmental issues. Pool chemicals, such as chlorine or salt, when allowed to seep into the soil, may impact groundwater purity. While nature filters much of this out, repeated leakage over time can have cumulative effects, especially in sensitive ecosystems.
Warning Signs of Water Migration and Leaks
Recognizing the signs of a leak early can prevent extensive damage. Common indicators include:
Persistent soggy or soft spots near the pool or plumbing lines
Cracking or lifting in pool decks
Loose or falling waterline tiles
Air bubbles in the pump basket or return lines
A constantly running autofill system
An unexplained spike in water or energy bills
Green patches of grass in dry weather or rings of dead grass near the pool
If you observe any of these, it’s wise to stop, investigate, and call a professional leak detection company.
Conclusion: Don’t Let a Leak Drain Your Property—Call Precision Leak Detection
Understanding where the water goes when your pool leaks is more than an academic exercise—it’s a critical part of protecting your investment. From plumbing leaks that create muddy yards to structural cracks that undermine your pool’s foundation to water migration that threatens your home’s integrity, the consequences are real and potentially costly.
The solution? Get ahead of the problem. If you suspect a leak, don’t wait. Precision Leak Detection specializes in locating hidden pool leaks with pinpoint accuracy. Our expert technicians use state-of-the-art tools and techniques to detect leaks in plumbing lines, fittings, pool shells, and equipment pads.
We provide thorough inspections, clear reports, and guidance on how to prevent the leak from causing further damage. Serving Palm Beach County and surrounding areas, Precision Leak Detection is the trusted name for accurate, professional, and honest pool leak detection services.
Don’t let a hidden leak erode your peace of mind. Contact Precision Leak Detection today and take the first step toward protecting your pool, property, and home.
