Are “environmentally safe” water treatments for hot tubs better alternatives to using chlorine?

Hot tubs are classified along with spas and swimming pools under Canada’s Pest Control Products Act and regulated by Health Canada’s Pest Management Regulatory Agency (PMRA). The only products the PMRA registers to control viruses, bacteria, and other micro-organisms in hot tubs are chlorine- and bromine-based sanitizers. Alternative treatments have yet to get the stamp of approval, but check PMRA for updates.

US regulators have been quicker to recognize alternatives: mineral purifiers and ionizers, which use copper, silver, and zinc to kill algae, bacteria, fungi, and viruses; and built-in ozonators that expose oxygen to UV light to create ozone, which is then injected into the water during the regular filtration to destroy pathogens.

These non-chemical products are available through Canadian tub dealers but they don’t actually leave you chemical free—they only reduce the need for chlorine or bromine sanitizers by up to 80 per cent, according to manufacturers’ claims. Ozonators will make chemicals about 25 per cent more effective. So for now, to be sure water is fully treated, you are stuck with varying amounts of unpleasant sanitizers. As for disposing of hot tub water, regardless of what’s in it, you’re legally required to drain it into your septic system.