Ask any pool leak detection technician in the Los Angeles area what they find most often, and the answer is almost always the same: the skimmer. Skimmer-related leaks account for a significant majority of pool water loss cases we investigate — and they're frequently misdiagnosed or overlooked entirely.
Understanding how your pool skimmer works, why it leaks, and what the warning signs are could save you thousands of dollars and thousands of gallons of wasted water.
What Is a Pool Skimmer?
Your pool skimmer is the rectangular opening built into the side of the pool wall, just below the waterline. It's connected to your pool's filtration system and draws in surface water (along with leaves, bugs, and debris) to keep the pool clean.
Most residential pools have one or two skimmers. They consist of:
- A plastic or concrete housing set into the pool wall
- A weir (flap) that controls water flow
- A basket that traps debris
- A connection pipe that runs underground to the pump
The junction where the plastic skimmer body meets the concrete or gunite pool shell is called the skimmer throat — and this is where the vast majority of skimmer leaks originate.
Why Skimmer Leaks Are So Common in Southern California
SoCal's climate creates ideal conditions for skimmer failure — even in pools that are well-maintained.
Ground movement & soil expansion
Los Angeles sits on expansive clay soils that swell when wet and shrink when dry. This constant movement creates stress at the skimmer-to-shell junction, eventually cracking the bond between the plastic housing and the surrounding concrete.
UV degradation
Southern California's intense sunlight degrades the plastic skimmer housing over time. Older skimmers become brittle and prone to cracking, especially around the face plate and neck area.
Thermal cycling
Hot days and cool nights cause the pool shell and skimmer housing to expand and contract repeatedly. Over years, this cycling creates micro-cracks at the seam between the two materials.
Age & wear
Most residential pools in LA were built 20–40 years ago. At that age, the original skimmer gaskets and faceplate seals have long exceeded their design life and are likely cracked, brittle, or completely deteriorated.
The 4 Most Common Skimmer Leak Points
1. The Skimmer Throat (Body-to-Shell Junction)
The most common leak point. The seam where the plastic skimmer body meets the gunite or plaster shell develops a gap over time. Water seeps through this gap, escapes behind the pool wall, and saturates the surrounding soil — often undetected for months.
2. The Skimmer Faceplate Gasket
The faceplate is the decorative cover held against the pool wall by two bolts. Behind it sits a rubber gasket. When this gasket deteriorates, water leaks through the bolt holes and around the faceplate. This is one of the easier and cheaper skimmer repairs.
3. The Skimmer Bottom Outlet Pipe
The pipe connecting the skimmer to the underground suction line can crack at the fitting connection, especially if the ground has shifted. This is a more serious leak that may require pressure testing to confirm.
4. Cracks in the Skimmer Housing Itself
In severe cases, the plastic skimmer body itself cracks — often longitudinally along the side walls. This type of failure typically requires a full skimmer replacement.
Signs You Have a Skimmer Leak
Skimmer leaks have some distinctive characteristics that can help identify them:
- Water level stabilises just below the skimmer opening — The pool stops dropping once the water level falls below the skimmer. This is a classic sign that the leak is at or near the skimmer.
- Wet or soft ground beside the pool — Especially on the side where the skimmer is located.
- Pump losing prime or pulling air — A crack in the skimmer throat or outlet pipe can allow air into the suction line.
- Visible cracks around the skimmer opening — Look for hairline cracks in the plaster or concrete around the perimeter of the skimmer mouth.
- Efflorescence (white staining) — White mineral deposits around the skimmer faceplate or on the pool wall below indicate water is migrating through cracks.
Can You Fix a Skimmer Leak Yourself?
Minor faceplate gasket replacements are within the capability of a handy homeowner — the parts are inexpensive and the process is straightforward. However, most skimmer leaks are not this simple.
Throat repairs, housing cracks, and underground pipe issues require professional diagnosis first to confirm the exact location of the leak. Applying pool putty or hydraulic cement to the wrong spot is a common DIY mistake — it may temporarily slow seepage but won't address the underlying structural issue.
Professional repair options include:
- Two-part epoxy injection into the throat gap (for small separations)
- Skimmer faceplate gasket replacement
- Full skimmer replacement (for cracked housing or severe separation)
- Underground pipe repair (for outlet line failures)
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