Pool Water Conservation: What Owners in the Algarve Need to Know About Water and Drought

If you own a pool in the Algarve, the last few years of water headlines will have made uncomfortable reading. Restrictions. Dam levels in the news every week. The Querença-Silves aquifer at less than 20 per cent capacity. The government floating higher tariffs for filling domestic pools. Municipal pools in Loulé shut entirely to conserve supply. In this context, pool water conservation has become a growing priority for owners across the region.

We have worked on pools across this region since 2008. We have lived through every drought cycle the Algarve has thrown at us, including the worst on record in 2023 and 2024, when 84 per cent of groundwater bodies dropped below the 20th percentile and the government formally declared an alert situation (The Portugal News, February 2024).

How serious is the water situation in the Algarve?

Serious over the long term, even in the years when the dams look full. Surface reservoirs recover quickly after a wet winter. The Querença-Silves aquifer, which is what most boreholes actually draw from, refills over years rather than months. That gap between what you see and what lies underneath is the part that matters.

The wet winter of 2025 brought genuine relief. By November of that year the Algarve's six main dams had recovered to 72 per cent capacity, and Odelouca and Odeleite, the two biggest, were approaching 80 per cent (The Portugal News, December 2025). José Pimenta Machado, the APA president, confirmed that urban supply was assured for three to four years even in a bad scenario.

Underground, the picture is different. Pimenta Machado said it plainly: "Some sectors say the drought is over, but nothing is over. It's a temporary situation; we were lucky now, but we have to prepare for the years to come" (The Portugal News, December 2025). The dams look healthy. The aquifers do not.

A 108 million euro desalination plant is going up in Albufeira, the first on the Portuguese mainland. It should be running by late 2026 or early 2027, producing 16 million cubic metres of drinking water a year (The Portugal News, October 2024). That covers roughly a fifth of the region's urban consumption. Climate models still show less rain arriving here over the coming decades. The plant is a lifeline, not a solution.

Cheap, unlimited water in the Algarve is finished. You can absolutely still have a pool. You just cannot pretend it does not use a resource the whole region is trying to manage better.

How much water does your pool actually lose?

A fairly standard pool here, 8 by 5 metres and 40 square metres of surface, loses between 150 and 250 litres a day to evaporation alone in July and August with no cover. That is a drop of roughly 3 to 4 centimetres a week. At the upper end of that range, a full summer season takes something close to 25,000 litres out of the pool.

Wind is the accelerant people forget about. The western coast, around Sagres, Lagos and parts of Aljezur, gets battered by Atlantic winds that strip moisture off the water surface. We have seen pools near Sagres lose water at nearly double the rate of a sheltered pool up in the Loulé hills.

Heating makes it worse. A heated pool evaporates faster because the warm surface creates a bigger temperature gap with the surrounding air. We have clients who run a PolyTropic heat pump all season without a cover. They are essentially heating the sky. A cover fixes this almost completely.

Then there are leaks. We find pools all the time that are losing hundreds of litres a day through a hairline crack in the shell or a weeping pipe joint, and the owner has written it off as ordinary evaporation. Our electronic leak detection equipment can tell the difference in one visit, with no need to drain the pool.

What actually reduces a pool's water consumption?

Covering it, before anything else. A solid cover cuts evaporation by around 95 per cent while it is in place, and evaporation is the largest ongoing loss from any pool. After that come ruling out leaks, automating the top-up so nobody is guessing with a hosepipe, and keeping the chemistry stable enough that the pool never needs draining to recover it.

Research carried out at California Polytechnic State University for the National Plasterers Council measured that reduction of around 95 per cent from a solid cover (Muleta, 2016). On a pool losing 200 litres a day, that is 190 litres kept in the water. Every day. All season.

The same study carries the caveat that matters most in practice: those figures assume the cover stays on. That is the real case for a proper slatted automatic cover over a bubble sheet you drag on and off by hand. Both suppress evaporation when they are in place. Only one of them is actually in place every night. We install DEL covers in solar and electric versions, and the clients who have them rarely think about water level at all.

The cover also holds heat in the water overnight, so the heat pump works less, and it keeps leaves and dust out, which means fewer chemicals and less strain on the filter.

After covers, the priority is leak detection. A pool with a small crack or a weeping pipe fitting can quietly lose more water than evaporation ever would. We are the only company in Portugal with electronic leak detection equipment. We pinpoint the leak without draining the pool and without guessing. If your water level is dropping faster than it should, have it checked.

For owners who are not on site all the time, and that includes a lot of our clients who split the year between the Algarve and the UK or elsewhere, an automatic water level controller makes a real difference. The INDYGO system we install connects to the MyIndygo app on your phone. It monitors the level around the clock, tops up automatically when it dips, prevents the pump from running dry, and tracks how much water the pool consumes over time. We have had clients change completely how they manage their pool after a month of looking at the consumption data.

Salt chlorination does not reduce evaporation. What it does is keep the water chemistry more stable, which means fewer situations where the only fix is to drain half the pool and start again. Pools on manual chlorine dosing swing in and out of balance more often, and every corrective partial drain wastes thousands of litres. We fit Sugar Valley Hidrolife systems.

Regular attention underpins all of this, whoever provides it. Algae blooms need shock treatment and sometimes partial draining. A cracked pump housing or a perished valve seal leaks water silently for weeks. Backwashing a dirty filter uses water every time. Problems caught early are problems that never reach the point of costing you a pool full of water.

One last thing. Do not let anyone talk you into draining your pool for routine work. There are very few situations where a full drain is necessary on a residential pool, and doing it throws away 40,000 to 80,000 litres of water plus every chemical dissolved in it. Even for refurbishment we try to minimise what gets dumped. If someone recommends a full drain, ask them why.

A note about responsibility

The gap between a well-run pool and a badly run one is staggering. A covered pool, no leaks, automatic top-up, proper care: perhaps 5,000 litres of fresh water across a whole season. An uncovered pool with a slow leak and no monitoring: 50,000 litres or more, gone, and the owner had no idea because nobody was tracking it.

The regional economy runs on tourism. A lot of that tourism runs on pools. Shutting them all down is not the answer. Running them properly is.

H2: Get in touch

If you want to get your pool's water consumption under control, or if you think something might be leaking and you are not sure, give us a call. We will come and look, tell you what we find, and give you honest advice on what is worth doing and what is not.

Get in touch

Frequently asked questions

Can I fill my pool during water restrictions in the Algarve?

It depends on the measures in force at the time, which change as reservoir levels change. Restrictions to date have included municipal pool closures and proposed tariff increases for filling domestic pools. Check the current position with your câmara municipal before any large fill.

How much water does a pool cover actually save?

Research at California Polytechnic State University measured around 95 per cent less evaporation from a covered pool, although that figure assumes the cover stays on (Muleta, 2016). On a 40 square metre pool losing 200 litres a day in high summer, a cover that is genuinely used every night keeps most of that water where it belongs.

Is my pool losing water to evaporation or to a leak?

Compare the pool against a bucket of pool water placed on the top step for 24 to 48 hours. Both lose water to evaporation at the same rate, so a pool level falling faster than the bucket's points to a leak. Electronic detection can then locate it without draining the pool.

Does a heated pool use more water?

Yes. Evaporation is driven by the difference between the water temperature and the air above it, so a heated pool loses more, particularly on cool nights. This is also why a cover pays twice on a heated pool, saving the water and the heat that would otherwise leave with it.

Do I need to drain my pool to have it maintained or refurbished?

Almost never for routine work, and less often than people assume even for refurbishment. A full drain on a residential pool throws away 40,000 to 80,000 litres along with the chemicals in it. If a full drain is proposed, ask what specifically requires it.