Cyprus summers are not gentle. When temperatures in Limassol or Paphos climb past 38°C for days at a stretch, and the sun sits high with little cloud cover, a full-sized residential pool can lose between five and ten centimetres of water per week purely through evaporation. That is a significant volume. Managing it properly affects your water chemistry, your pump and filter performance, and your water bill.
How Much Water Are You Actually Losing?
A standard 8×4 metre pool losing seven centimetres of depth per week is losing roughly 2,240 litres in seven days. Across a ten-week Cypriot high summer, that adds up to more than 22,000 litres from evaporation alone, before you account for splash-out, backwashing, or topping up after chemical corrections.
The rate depends on a few variables: surface area, air temperature, humidity (which in July and August can drop very low inland), wind speed, and sun exposure. Pools in exposed coastal plots near Limassol marina or Coral Bay tend to lose more to wind-driven evaporation than sheltered garden pools. Pools running warmer water, which happens naturally when your pool is in full sun without shade sails or a cover, evaporate faster.
The practical benchmark: if your water level is dropping more than two centimetres per day without a cover, check for a leak. Evaporation alone does not typically exceed that rate, even in the hottest conditions.
Topping Up: The Chemistry Problem Nobody Mentions
When you top up from a Cypriot mains supply, you are adding hard water. The total dissolved solids and calcium hardness levels in municipal water across most of the island are high, which is a direct result of the limestone geology and the desalination processes used in the water network. Repeatedly topping up a pool that has also been concentrating minerals through evaporation creates a compounding problem.
Evaporation removes pure water but leaves everything else behind: calcium, magnesium, carbonates, and whatever chemical residues are already in the pool. The total dissolved solids (TDS) level climbs. Calcium hardness rises. The water becomes harder and more scale-prone. You may notice a white chalky residue forming on tile grout, on the waterline, or on your heating elements if you have a heat pump.
What to monitor during a heatwave
- Check calcium hardness weekly rather than fortnightly. Target range is 200–400 ppm.
- Monitor TDS levels. Once TDS exceeds around 1,500 ppm above your fill water baseline, partial draining and dilution becomes necessary.
- Test pH more frequently. Evaporation and high UV exposure interact with your chlorine and carbonate balance. pH tends to drift upward in Cypriot pools during summer.
- If you are using a saltwater chlorinator, high TDS from top-up water can affect salt readings on your control panel. Calibrate accordingly.
Reducing Evaporation: What Actually Works
Pool covers
A well-fitted solar or thermal cover is the single most effective tool for reducing evaporation. Studies consistently show that covers reduce evaporation by 90–95% when the pool is not in use. For a villa rental property or private home where the pool sits unused overnight and through midday, the water savings across a summer are substantial.
Bubble covers (solar blankets) are the most common choice in Cyprus because they also add some passive heating, which is rarely needed in July but extends your shoulder season in April and October. The drawback is handling: a large cover on a hot afternoon is awkward, and the UV degradation rate in Cyprus is faster than in northern European climates. Budget for replacement every two to three seasons.
Liquid solar covers, which use a thin monomolecular alcohol layer to slow evaporation, are an option for pools where a physical cover is impractical. They reduce evaporation by around 30–40%, are safe for swimmers, and require weekly dosing. They are not a substitute for a proper cover but they are meaningfully better than nothing.
Shade and wind
Wind is an underappreciated factor. A light breeze across the surface increases evaporation significantly by removing the thin layer of humid air that would otherwise slow the process. Shade sails or pergolas over part of the pool reduce both direct evaporation and heat gain in the water. In exposed plots on the Akamas peninsula or on hillside villas above Limassol, this makes a practical difference.
Dealing With Dust Events
Cyprus experiences Saharan dust incursions multiple times each summer. These carry fine particulate matter that settles on your pool surface, entering the water and placing additional load on your filter. During and immediately after a dust event, you will likely need to top up slightly (dust and debris cause minor additional water displacement and loss during cleaning), backwash your sand filter, and retest your chemical balance. Phosphate levels can also spike, which encourages algae growth if your sanitiser level dips simultaneously. It is worth keeping a spare supply of phosphate remover during summer months.
Setting Up a Simple Monitoring Routine
You do not need to be obsessive about this, but a consistent weekly check during June through September saves you from expensive corrections. Each week: check water level and record the drop, top up as needed, test calcium hardness, pH, and free chlorine, and run a quick visual inspection of tile grout and the waterline for early scale formation.
If you are managing a holiday rental in Paphos or Larnaca, build this into your between-guest changeover checklist. A pool that goes two weeks unmonitored in August can develop chemistry problems that take considerably more time and expense to correct than prevention would have required.
If you want a professional eye on your pool’s condition heading into summer, or if you are already seeing scale build-up or unexplained water loss, get in touch with us at Pool Cleaning Cyprus. We work across Limassol, Paphos, Nicosia, Larnaca, and the surrounding areas. Call or email us to arrange a visit.