How Much Water Should Your Pool Actually Lose? Understanding Normal Evaporation vs Pool Leaks
Pool leaks in Cape Town account for a large amount of the leak detection queries I receive. As a leak detection specialist here in Cape Town, I get calls every week from pool owners asking the same question: "Werner, my pool is losing water - is this normal, or do I have a leak?" It's a great question, and here is some information that can help us discover what's normal and what should have you reaching for the phone to call a professional.
Normal Pool Water Loss: What to Expect
It is important to acknowledge that every pool loses water naturally. This is completely normal and happens through several processes:
Evaporation: Your Pool's Natural Process
Evaporation is by far the biggest culprit when it comes to normal water loss. Here in Cape Town, with our warm, dry summers and occasional berg winds, evaporation can be quite significant.
Typical evaporation rates:
- Summer months: 6-12mm per day (that's about 0.6-1.2cm)
- Winter months: 2-5mm per day
- Windy days: Can increase by 50-100%
For a standard 8m x 4m pool (32 square meters), this translates to:
- Summer: 190-380 litres per day
- Winter: 65-160 litres per day
That might sound like a lot, but it's perfectly normal!
Other Normal Water Loss
Beyond evaporation, you'll also lose water through:
- Splash-out during swimming: 50-200 litres per active swimming session
- Backwashing your filter: 300-1000 litres depending on your system
- Regular maintenance and cleaning
The Simple Bucket Test
Here's a trick I always share with my clients: place a bucket filled with pool water on your pool step (so it's partially submerged). Mark the water level in both the pool and bucket. After 24 hours, if they've both dropped by the same amount, you're dealing with normal evaporation. If the pool has dropped significantly more - you might have a leak.
When Water Loss Becomes a Problem: Identifying Leaks
A leak can turn your relaxing pool into a costly headache faster than you might think.
Small Leaks, Big Problems
Even a tiny leak can waste enormous amounts of water. Let me put this into perspective:
A pinhole leak (just 2mm diameter) can lose:
- Up to 1,500-3,000 litres per day
- That's 10-20 times normal evaporation!
- Over R200 per day in Cape Town water costs
- Nearly R6,000 per month if left unchecked
A small crack or loose fitting (5mm gap) can lose:
- Up to 10,000-15,000 litres per day
- Your entire pool volume in 2-3 days
- Over R1,000 per day in water costs
Red Flags That Suggest a Leak
After years in this business, I've learned to spot the warning signs:
- Consistent water loss: More than 12mm per day, even on calm days
- Chemical imbalances: Constantly having to add chemicals
- Wet spots around the pool: Especially near equipment
- Cracked or settling pool deck
- Air bubbles in return lines: Often indicates suction-side leaks
- Algae growth despite proper chemical levels: Fresh water dilutes your chlorine levels
Video showing where the gas is pinpointing the leaking pool pipe
Video showing dye disappearing through a leaking inlet
The Real Cost of Ignoring Pool Leaks
In my experience, the biggest mistake pool owners make is thinking "it's just a small leak." Let me share what I've seen:
Financial Impact
- Water costs: R300-1,500 per day depending on leak size
- Chemical waste: 2-3 times normal chemical usage
- Energy costs: Pump working overtime to maintain circulation
- Structural damage: Water undermining foundations can cost tens of thousands to repair
Environmental Impact
Here in the Western Cape, where we've experienced severe droughts, wasting thousands of litres daily through leaks isn't just expensive - it's irresponsible. I've detected leaks wasting enough water to supply several households.
When to Call a Professional
As much as DIY checks and maintenance help, leak detection requires specialized equipment and expertise. You should call a professional when:
- Water loss exceeds 15mm per day consistently
- The bucket test shows excessive pool water loss
- You notice any of the red flags mentioned above
- You suspect but can't locate the source
What Professional Leak Detection Involves
When I arrive at a property, I use a variety of methods including:
- Acoustic leak detection equipment: Pinpoints exact leak locations
- Pressure testing: Tests all plumbing lines individually
- Dye testing: Confirms suspected leak points
- Gas leak detection: Can reveals hidden leaks in pipes
Most leaks can be located and assessed within 2-3 hours, potentially saving you thousands in water bills and damage.
Making the Right Decision
The bottom line? Normal evaporation in Cape Town can account for 200-400 litres per day from your pool. Anything significantly above this, especially if it's consistent regardless of weather conditions, warrants investigation.
Remember, a small leak detected early might cost a few hundred rand to fix. The same leak ignored for months can result in structural damage costing tens of thousands.
If you're unsure about your pool's water loss, don't gamble with guesswork. A professional assessment provides peace of mind and often pays for itself within days through water savings alone.
DISCLAIMER: The water loss rates, evaporation figures, and cost estimates provided in this article are based on industry experience and general calculations. Actual rates may vary significantly depending on specific pool conditions, local climate factors, water pressure, leak size and location, current municipal water tariffs, and other variables. These figures should be used as general guidance only. For accurate assessments of your specific situation, professional leak detection and current municipal tariff information should be consulted. Leak Detection Specialist Cape Town accepts no liability for decisions made based on these general estimates.
