Is It Evaporation — or Something More Serious?
If you own a pool in Cairns, you’ve probably noticed the water level dropping from time to time. In tropical North Queensland, some water loss is completely normal — especially during hot, humid weather. But when you find yourself constantly topping up your pool, it could be a sign of a bigger issue.
At Allan’s Pool Shop, one of the most common questions we hear from pool owners is:
“Why does my pool keep losing water?”
The answer can range from simple evaporation to hidden leaks, damaged equipment, or plumbing problems. Knowing the difference can save you hundreds — or even thousands — in water bills, chemical costs, and future repairs.
In this guide, we’ll explain the most common reasons pool water levels drop in Cairns and how to tell whether your pool needs professional attention.
How Much Pool Water Loss Is Normal?
Before assuming there’s a leak, it’s important to understand that all pools naturally lose some water.
In Cairns, pools can lose:
- Around 3–5mm of water per day during normal conditions
- More during hot weather, windy days, or periods of heavy pool use
- Additional water after backwashing filters or cleaning equipment
Tropical heat, strong UV exposure, and high humidity all contribute to faster evaporation rates.
If your pool is losing significantly more than this — especially several centimetres per week — it’s time to investigate further.
1. Evaporation from Cairns’ Tropical Climate
Cairns weather is one of the biggest reasons pools lose water regularly.
Factors That Increase Evaporation
- High temperatures
- Strong sun exposure
- Wind across the water surface
- Heated pools
- Water features and fountains
- Long pump run times
Even though Cairns is humid, evaporation still occurs rapidly during sunny periods.
How to Reduce Evaporation
You can minimise water loss by:
- Using a pool cover
- Running water features only when needed
- Reducing excessive splashing
- Installing shade where possible
- Running your pump during cooler hours
A good pool blanket can significantly reduce evaporation and help maintain water temperature at the same time.
2. Hidden Pool Leaks
If your pool water level drops quickly even when the weather is mild, you may have a leak.
Leaks can occur in:
- Pool shells
- Vinyl liners
- Skimmer boxes
- Return lines
- Underground plumbing
- Pump or filter equipment
Small leaks often go unnoticed for months because the water loss seems gradual at first.
Signs Your Pool May Have a Leak
Watch for:
- Constant need to top up water
- Wet or soggy areas around the pool
- Cracks in paving or pool surrounds
- Air bubbles in return jets
- Rising water bills
- Pool chemicals becoming unbalanced quickly
- Water level dropping below skimmer openings
In Cairns, heavy rainfall and shifting ground conditions can sometimes worsen structural movement around pools and underground pipes.
3. Problems with Pool Equipment
Sometimes the leak isn’t in the pool itself — it’s in the equipment.
Common equipment-related water loss issues include:
Pump Leaks
Pool pumps can develop:
- Cracked housings
- Loose unions
- Worn seals
- Dripping fittings
Filter Problems
Damaged filters or faulty multiport valves can allow water to leak during operation.
Chlorinator Leaks
Salt chlorinators occasionally develop small leaks around fittings or cells.
Because equipment areas are often already wet, these leaks can easily be overlooked.
Regular inspections help identify small issues before they become major problems.
4. Splash-Out and Heavy Pool Use
Sometimes the explanation is simple.
If your pool gets lots of use — especially by children — water loss from splashing can add up quickly.
Water can also be lost through:
- Cannonballs and jumping
- Pool parties
- Overflow from heavy rain
- Cleaning and vacuuming
- Backwashing the filter too frequently
While occasional splash-out is normal, excessive water loss from frequent backwashing may indicate your filter system needs attention.
5. Structural Cracks or Surface Damage
Older pools in Cairns can sometimes develop structural cracks due to:
- Soil movement
- Ageing materials
- Groundwater pressure
- Tree root movement
- Improper construction
Concrete pools may develop hairline cracks that slowly leak water over time.
Fibreglass pools can also experience:
- Gelcoat damage
- Surface blistering
- Cracks around fittings
Even small structural issues should be inspected early before they worsen.
The Bucket Test: A Simple Way to Check for Leaks
One of the easiest ways to tell whether your pool has a leak is by performing a bucket test.
How to Do a Bucket Test
- Fill a bucket with pool water.
- Place it on a pool step.
- Mark the water level inside the bucket.
- Mark the pool water level outside the bucket.
- Leave it for 24 hours with the pump running normally.
- Compare the water loss.
If the pool loses significantly more water than the bucket, there’s a good chance you have a leak.
This simple test helps separate normal evaporation from abnormal water loss.
Why Ignoring Water Loss Can Become Expensive
Many pool owners delay investigating leaks because the water loss seems minor.
Unfortunately, even small leaks can cause:
- Higher water bills
- Increased chemical costs
- Pump damage
- Soil erosion under the pool
- Structural movement
- Damage to nearby paving and landscaping
The longer a leak continues, the more expensive repairs often become.
When to call a professional
You should consider professional leak detection if:
- You’re topping up the pool more than once a week
- The water level drops rapidly
- You notice wet patches around the pool
- Your equipment area constantly leaks
- The bucket test confirms abnormal water loss
- Your chemicals won’t stay balanced
Professional testing can locate leaks in underground plumbing, pool shells, fittings, and equipment systems without unnecessary digging.
How Allan’s Pool Shop Can Help
At Allan’s Pool Shop, we help Cairns pool owners identify and solve water loss problems before they become major repairs.
Our team can assist with:
- Pool inspections
- Leak detection guidance
- Equipment checks
- Pump and filter troubleshooting
- Water testing and balancing
- Replacement parts and pool products
Whether your pool is losing water due to evaporation, equipment issues, or a hidden leak, we’ll help you find the cause and recommend the right solution.
In Cairns’ tropical climate, some pool water loss is completely normal — but constant topping up shouldn’t be ignored.
Understanding the difference between evaporation and leaks can help you protect your pool, reduce running costs, and avoid major repairs down the track.
If you’re unsure why your pool water level keeps dropping, the team at Allan’s Pool Shop is here to help. Contact us today.
Need Help Finding a Pool Leak?
Visit Allan’s Pool Shop or speak with our team for expert pool advice, equipment checks, and maintenance support tailored for Cairns conditions.