Residential swimming pools | A more eco-friendly dive

Quebec is the kingdom of the swimming pool in North America. However, this backyard gem consumes a lot of water and energy, in addition to releasing chemicals into the environment. How can you cool off while minimizing your carbon footprint… and easing your environmental conscience?

The ecological impact of a swimming pool is not to be neglected, immediately acknowledges Jacques Lainé, administrator of the Association des marchands de piscines du Québec (ACPQ), adding that with half a million swimming pools (one pool for every 16 inhabitants) listed in the province, the consequences on the environment are tenfold.

In response to these concerns, the industry is increasingly making real efforts to provide more environmentally friendly and energy-efficient accessories, he says. “Manufacturers are trying to minimize the use of chemicals and maximize the life of the equipment so it doesn’t end up in landfills.”

Jacques Lainé highlights, as an example, the appearance of filters with reusable cartridges “which can be simply cleaned before being put back in place”. They avoid the discharge of chemical residues into the water distribution network caused by cleaning the sand of a conventional filter.

The choice then comes back to the consumer, continues Mr. Lainé. “It is certain that a swimming pool manufactured in Quebec reduces GHG emissions from transportation and offers a longer lifespan than a product imported from China, sold in supermarkets. Usually, customers react favorably to this argument.”

Finally, the owner is encouraged to take a series of actions, such as using a solar cover, to preserve the heat of the water. “There is equipment for that,” recalls Jacques Lainé.

Energy-intensive

Using a swimming pool can represent a third of the annual electricity bill of an average home, according to Hydro-Québec. A bill that varies depending on the type of equipment used, for example to heat the pool water.

Installing a simple timer can reduce this energy demand. “For example, limiting the operation of the filtration system for 6 to 12 hours is enough to keep the water quality intact,” suggests Mr. Bouchard.

A variable-speed programmable pump also offers energy savings, says Jacques Lainé. “Its speed varies according to the needs of the day. At night, it simply runs at idle.”

On the heating side, a heat pump is three times more efficient than a natural gas pool heater. Lowering the set point by two degrees Celsius and using a solar blanket also contribute significantly to reducing the energy impact, Cendrix Bouchard points out.

The rejects

Water treatment causes chemicals to be released into the sewers or directly into the environment.

For ecological reasons, more and more owners are turning to salt pools. Less irritating for swimmers, these systems (costing between $800 and $2,000) still release around 100 kg of salt during annual emptying, laments Écohabitation.

Three less damaging options have appeared on the market, reports this organization dedicated to sustainable construction: ionization, ozonation and the UV reactor.

Ionization works with electrodes that release metal ions to eliminate algae, bacteria and viruses. This system (costing between $500 and $2,000) can reduce the amount of chlorine and other chemicals by 70 to 90%.

Ozonation is an environmentally friendly process used in many drinking water treatment plants. Electrodes or UV rays transform oxygen (O_⁠2) in ozone (O^⁠_⁠3), a powerful oxidant which is then introduced into the water. It also allows a reduction in the quantities of chlorine.

The UV reactor circulates water in a cylinder equipped with a UV lamp. It can eliminate 99.9% of bacteria, algae and viruses. This system has fewer negative impacts on water than other treatment methods and offers good value for money, according to Écohabitation.

The ozone generator with UV combines these two processes. It does not disrupt the water balance (pH), its scaling is limited and it does not create corrosion. It also helps limit irritation to the skin, eyes and respiratory system, says Écohabitation. This system (costing $1,200 to $2,000) requires regular maintenance, and the UV lamps must be replaced approximately every two years ($125).

The materials

Each type of pool does not have the same carbon footprint. Each is distinguished by its material, design and lifespan.

An in-ground pool will last almost twice as long as an above-ground pool, says Jacques Lainé. “Quebec manufacturers make fiberglass pools that are easy to install and don’t require concrete,” he says, before pointing out that an above-ground pool made of steel or synthetic resin can last up to 15 years.

“The worst are inflatable above-ground pools,” says Emmanuel Cosgrove, co-founder and CEO of Écohabitation. “They’re made entirely of non-recyclable plastic and they only last one summer, two at the most. It’s a disposable technology that quickly ends up in the landfill.”

Other options

Relaxation and swim spas may seem like good alternatives to a swimming pool, especially for owners of small properties. “However, they are equipped with several pumps,” notes Mr. Lainé.

The perfect pool does not exist, believes Emmanuel Cosgrove. Nevertheless, the small European-style pool, long and narrow, is a good option. “It uses less water and, as a result, requires less energy for filtration and heating,” he says.

Water features and misters are also solutions to consider to combat the heat, he adds. The best choice, however, remains municipal swimming pools, according to him.

The swimming pool tax

Since 2017, several Quebec municipalities have imposed a tax on swimming pools in an effort to limit behaviors that are harmful to the environment. This tax very often amounts to a few dozen dollars per year, regardless of the type and volume of the pool.

This eco-tax measure is considered “imperfect” by Tommy Gagné-Dubé, assistant professor of taxation at the University of Sherbrooke.

“When you listen to the debates at city council meetings, you realize that the goal of elected officials is not to eliminate swimming pools or limit their size. They simply aim to make people pay [les propriétaires] for the cost of water treatment,” emphasizes this researcher at the Chair in Taxation and Public Finance.

“This tax is therefore more in line with a user-pays logic rather than a desire to change behavior,” he continues.

For the ecotax measure to hit its target, according to Mr. Gagné-Dubé, alternative solutions must be offered to citizens. “If we impose a tax on swimming pools, what do we offer people so they can cool off during heat waves?” he concludes.