One of the most common questions swimming pool owners ask is, “Why does my pool keep losing water until it reaches the bottom of the tile, and then suddenly stop?”
If you’ve noticed this happening in your pool, there is a very good chance the leak is related to your skimmer system. In fact, when homeowners call us because their pool consistently drops to the same level and then stabilizes, the skimmer is often one of the first places we investigate.
The reason is simple. The skimmer sits at the waterline of the pool, and several critical components within the skimmer assembly can develop leaks over time. When the water level falls below the leaking area, water can no longer escape through that opening, so the water loss stops.
In this article, we’ll explain three of the most common swimming pool skimmer leaks we encounter during professional leak detection inspections and show you what to look for before calling a professional.
Understanding Why Water Stops at a Specific Level
Before diving into the individual leak sources, it’s important to understand a basic principle of leak detection.
Water can only leak from an opening that is submerged beneath the waterline. If a crack, separation, or plumbing leak occurs at a certain elevation, the pool will continue to lose water until the water level drops below that leak.
Once the leak is exposed to air, water can no longer escape, and the water level stabilizes.
This is why the level at which your pool stops leaking is often one of the most important clues for determining the location of the leak.
When a pool consistently stops at or near the bottom of the tile line, the skimmer becomes a primary suspect.
Leak Source #1: The Skimmer Throat Cold Joint
The most common swimming pool leak we encounter is found inside the skimmer throat.
The skimmer throat is the opening in the pool wall where surface water flows into the skimmer basket. It appears to be a simple opening, but it contains one of the most vulnerable joints in the entire pool structure.
When a swimming pool is constructed, the plastic skimmer housing is installed in the concrete shell of the pool. Where these two materials meet, a joint is created. This connection is commonly called a “cold joint.”
Because plastic and concrete expand and contract at different rates over time, this area experiences constant movement. Years of exposure to temperature changes, ground movement, deck settlement, and normal aging can eventually cause the waterproofing material inside the joint to deteriorate.
When that happens, water begins escaping through the separation.
At Precision Leak Detection, skimmer throat leaks account for a significant percentage of the structural leaks we locate every year. In many cases, homeowners are surprised to learn that a tiny separation hidden inside the skimmer throat can result in substantial water loss.
How to Inspect the Skimmer Throat
A close visual inspection is often the first step.
Carefully examine:
- The entire perimeter of the skimmer throat
- The joint where the plastic skimmer meets the concrete pool shell
- The corners of the opening
- Tile grout joints surrounding the skimmer
- The transition between tile and plaster
Many skimmer throat leaks are extremely small and difficult to see with the naked eye. A dye test can often help identify these hidden leaks by showing where water is being drawn from the pool.
Find Pool Leaks Like a Pro
Dye testing is one of the fastest ways to locate leaks around skimmers, lights, returns, fittings, and cracks.
View Dye Test Kit →Recommended DIY tool for swimming pool leak detection.
Can It Be Repaired?
In some situations, homeowners can temporarily slow or stop a leak using pool putty or underwater epoxy products.
After identifying the leaking area with dye testing, the repair material can be packed into the joint to create a temporary seal.
However, it is important to understand that these repairs are often temporary. If the skimmer throat has significant movement or deterioration, permanent repairs or skimmer replacement may eventually be required.
Leak Source #2: Cracks in the Plastic Skimmer Housing
The second common cause of water loss is a crack in the plastic skimmer housing.
The skimmer housing is the plastic box located beneath the skimmer lid. This component houses the skimmer basket and serves as the connection point between the pool and the plumbing system.
Over time, plastic becomes brittle from age, UV exposure, shifting soil conditions, and deck movement. As a result, cracks can form within the skimmer body.
These cracks are often difficult to locate because they may be:
- Extremely thin
- Hidden beneath discoloration
- Located inside corners
- Running vertically down the housing walls
- Hidden along factory seams
In some cases, the crack may be nearly invisible until dye testing confirms water movement.
Areas to Examine Closely
When inspecting a skimmer housing, pay close attention to:
- Vertical walls
- Horizontal seams
- Corners
- Plumbing connections
- The junction where the upper and lower sections meet
- The opening leading into the skimmer throat
Many skimmer housings develop cracks directly along manufacturing seams. These cracks can be difficult to identify without careful inspection and dye testing.
Temporary vs. Permanent Repairs
As with skimmer throat leaks, small cracks can sometimes be patched using pool putty or underwater epoxy.
If the crack is minor and structural movement is limited, the repair may provide a reasonable temporary solution.
However, severely cracked skimmers often require complete replacement. If the housing has extensive damage or ongoing movement from deck settlement, replacement is usually the most reliable long-term solution.
Patch Small Pool Leaks Fast
Pool putty can help temporarily seal small leaks around skimmers, fittings, lights, tile lines, and minor cracks while underwater.
View Pool Putty →Useful for temporary DIY swimming pool leak repairs.
Leak Source #3: A Broken Skimmer Plumbing Line
If you’ve thoroughly inspected the skimmer throat and skimmer housing without finding a leak, the next possibility is the plumbing connected to the skimmer.
This is often where professional leak detection becomes necessary.
Unlike structural leaks that can sometimes be visually identified, underground plumbing leaks typically require specialized testing equipment.
How Plumbing Leaks Occur
Skimmer plumbing lines can become damaged for a variety of reasons, including:
- Ground settlement
- Deck movement
- Tree root intrusion
- Construction damage
- Age-related pipe failure
- Improper installation
When a skimmer line breaks underground, water may escape into the surrounding soil every time the circulation system operates.
In some cases, homeowners notice wet spots in the yard, sinking soil, or unusual water accumulation near the equipment pad.
Other times, there may be no visible evidence at all.
How Professionals Test Skimmer Plumbing
Professional leak detection companies use pressure testing equipment to isolate and evaluate plumbing lines.
The process generally involves:
- Plugging the plumbing line inside the pool.
- Isolating the line at the equipment pad.
- Pressurizing the line with air or water.
- Monitoring pressure loss.
- Using specialized listening equipment to pinpoint the break location.
This testing allows technicians to determine not only whether a line is leaking, but also where the leak is located underground.
Temporary Solutions for Broken Skimmer Lines
In some situations, immediate excavation may not be necessary.
If a pool has multiple skimmers, it may be possible to temporarily abandon the damaged line by plugging it at both ends.
This prevents water loss while allowing the remaining skimmer(s) to continue operating.
While this isn’t a permanent repair, it can provide homeowners with additional time to plan for future repairs.
When Should You Call a Professional?
Many homeowners can perform basic visual inspections and dye testing on their own.
If you identify a leak within the skimmer throat or skimmer housing, a temporary repair may be worth attempting before pursuing more extensive repairs.
However, if:
- Dye testing reveals nothing
- Water continues dropping to the same level
- You suspect an underground plumbing leak
- The pool is losing significant amounts of water
- Previous repairs have failed
It is usually time to schedule a professional leak detection inspection.
Professional testing can save substantial time, money, and frustration by accurately identifying the source of water loss before unnecessary repairs are performed.
Frequently Asked Questions
Why does my pool always stop leaking at the same level?
When a pool consistently stops at the same elevation, it usually indicates that the leak is located at that level. Once the water falls below the leak, it can no longer escape.
Is the skimmer the most common place for a pool leak?
Yes. Skimmer throat leaks and skimmer housing leaks are among the most common structural leaks found in swimming pools.
Can I fix a skimmer leak myself?
Minor leaks can sometimes be temporarily repaired using pool putty or underwater epoxy. However, permanent repairs often require professional service.
How do I know if my skimmer line is broken?
Pressure testing is the most reliable method. A professional leak detection company can determine whether the line is leaking and often locate the exact break.
Can a cracked skimmer cause major water loss?
Absolutely. Even small cracks can allow significant amounts of water to escape over time.
Does deck settlement cause skimmer leaks?
Yes. Deck movement and soil settlement frequently place stress on skimmer components, leading to cracks and joint separations.
How much water loss is considered normal?
Most pools lose approximately 1/8 to 1/4 inch of water per day from evaporation, depending on weather conditions. Anything significantly greater may indicate a leak.
Will pool putty permanently repair a skimmer leak?
Usually not. Pool putty is often best viewed as a temporary solution until permanent repairs can be completed.
Can a skimmer leak damage surrounding structures?
Yes. Long-term water loss can contribute to soil erosion, deck settlement, and structural movement around the pool.
What is the first thing I should check if my pool stops at the bottom of the tile?
Begin by inspecting the skimmer throat and performing dye testing around the skimmer assembly.
Need Professional Pool Leak Detection?
If your swimming pool is losing water and you suspect a skimmer leak, Precision Leak Detection can help.
Our comprehensive leak detection process includes:
- Professional dye testing
- Underwater inspections
- Hydrophone leak detection
- Pressure testing of plumbing systems
- Precise leak location services
We proudly serve homeowners throughout Palm Beach, Martin, St. Lucie, and Broward Counties, as well as surrounding South Florida communities.
If you’re tired of adding water to your pool every few days, contact Precision Leak Detection today to schedule a professional inspection and get answers before costly damage occurs.
Join the Discussion
Have questions about a swimming pool skimmer leak? Have you successfully repaired a skimmer throat or skimmer housing in your own pool?
Leave a comment below and join the discussion. We’d love to hear about your experience and help answer any questions you may have about pool leak detection.
