While some people may be concerned about the presence of chlorine in swimming pools and the effect it may have on the environment, there are other impacts to consider.
Swimming pools are energy intensive due to the use of pumps and other equipment, and they also lose a lot of water due to evaporation.
Here’s everything you need to know about the environmental impact of swimming pools.
1. How Do Swimming Pools Affect the Environment?
You may already know that chlorine is used in swimming water, but there are other chemicals too.
Pools can also be treated with bromine and ozone, or even ultraviolet radiation, in order to disinfect the pool.
While too much chlorine can be uncomfortable and burn the eyes of swimmers or cause skin irritation, generally, it is safe.
When added to a swimming pool, chlorine reacts with other compounds in water and turns into another substance, usually hypochlorous acid and hypochlorite, which can be in the form of sodium hypochlorite or calcium hypochlorite.
It is extremely unlikely that chlorine in a swimming pool will form chlorine gas, which is poisonous, as it entails combining chlorine with other chemicals.
Research found hypochlorous acid was non-toxic for humans and animals and did not appear to be detrimental to the environment.
However, hypochlorous acid may play a role in why you are more likely to get sunburned in a swimming pool.
As a disinfectant, sodium hypochlorite is quite potent; when used in cleaning products, very little is needed to kill pathogens.
This compound is also highly reactive, which means it can disappear quickly should it enter the environment.
So, when it comes to pools, this means there should not be a need for excess chemical use.
However, swimming pool water may not contain the same concentrations of these compounds.
Some halogenated by-products of chlorinated swimming pool water include trihalomethanes, haloacetic acids, and dichloroacetonitrile – some of these substances will evaporate or react with other compounds in the pool.
While some of these substances can form toxic dioxins and furans in acidic environments, pools are typically neutral or basic, so in normal circumstances, this should not be a concern.
Like chlorine, bromine and ozone also react in pool water to form another compound.
Bromine and ozone form hypobromous acid, which can then react with other compounds in the swimming pool and create bromide.
Bromide can also form disinfection by-products (DBPs) like bromate and bromoform.
Research suggested that these DBPs may be more toxic than analogous chlorinated compounds, with brominated haloacetonitriles having a stronger cytotoxic and genotoxic effect than analogous chlorinated DBPs.
Pools can also be treated with algaecides.
When these substances enter the environment, they can harm other marine life.
Outdoor pools can be hazardous to wildlife if they are not covered or fenced off.
You may have noticed quite a lot of insects floating around outdoor pools.
This is because insects, like bees, need water, but they can drown in pools if they try to use them as a water source.
With the changing climate, they may struggle to find water elsewhere, and although it seems negligible, a third of insect species are considered endangered.
Swimming pool water does not last forever.
While some private pool owners may get several years out of their pool water with constant maintenance, commercial pools could replace the water every year.
An average pool could contain 62,815 liters of water, which is a huge amount to discard and replace.
A pool will also lose water due to evaporation, so it will need to be topped up regularly, but this figure can vary based on whether a pool cover was used, if it was an outdoor pool, and the climate.
For example, a swimming pool in Chicago, Illinois, could lose 3,266 liters (863 gal) due to evaporation, whereas a pool in Phoenix, Arizona, could lose 20 times more (59,203 liters or 15,639 gal).
2. Do Swimming Pools Contribute to Climate Change?
Swimming pools do contribute to climate change.
Building the swimming pool in the first place requires energy and resources.
Then, the maintenance of the pool throughout its lifespan also requires energy from the likes of pumps, manufacturing and applying disinfectants, or UV lighting.
Most energy use worldwide is still primarily reliant on fossil fuels, so this is unsustainable.
The carbon footprint of a swimming pool could vary based on whether it is an indoor or outdoor pool, the location, and the size.
For example, an average swimming pool in Seattle, Washington, could be responsible for approximately 134 kg of carbon dioxide equivalent, but a similar swimming pool in Tampa, Florida, could be behind a whopping 2,492 kg of CO2e.
This appears to be because swimming pools in warmer regions use a pool pump more and treat them with more chemicals, as the sun’s rays can impact how effective they are.
In Phoenix, Arizona, homeowners with a swimming pool could see it account for 22% of their electricity use and 13% of their water use.
3. Can Swimming Pools Be Eco-Friendly?
Swimming pools can cut down on emissions and water waste by using a pool cover when the pool is not in use.
Pool covers can reduce water consumption by 30% to 50% and chemical consumption by 35% to 65%.
Solar-powered pool pumps would also reduce emissions drastically.
Natural swimming pools are also a more sustainable choice.
Natural swimming pools are not the same as natural lakes or ponds as they need to be manufactured, so there is still an environmental impact associated with construction.
These pools are not treated with chemicals; instead, they use a regeneration zone where the water goes through a filter, such as a gravel filter or natural plant filtration.
Natural swimming pools may also be better for wildlife as animals or insects are drawn to the regeneration zone and form an ecosystem.
However, they still require some maintenance, such as removing debris from the water and offsetting water loss due to evaporation.
4. Are Saltwater Pools More Eco-Friendly?
Saltwater pools may be a little more sustainable but not considerably so.
They still need to be treated with a little bit of chlorine, but less than standard swimming pools.
Saltwater pools use salt chlorine generators which are electric filtering systems, and they also still use pumps, so they do not eliminate energy use.
These pools are not immune to water loss, and the water will still need to be replaced.