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OBC DIVISION B · PART 3 · SECTION 3.12 — PUBLIC SPAS

What are the water treatment and recirculation requirements for public spas in Ontario?

Public spas must have a recirculation and treatment system that continuously filters and disinfects the water, sized to turn the spa volume over quickly given the high bather load and hot water, with make-up water and drainage arranged to protect the potable supply.

Code reference
Section 3.12 requires public spas to be served by recirculation systems that filter and chemically treat the water at a rate adequate for the spa volume and intended bather load, with equipment for disinfection and water quality control, backflow protection on make-up water connections, and drainage arrangements suitable for periodic emptying and cleaning.
OBC Division B, Section 3.12 (Public Spas)

Paraphrased for clarity — open this provision in the BUILDAiD Library for the exact wording.

What this means in practice

Hot, agitated, heavily loaded water degrades fast, so spa turnover rates are much more aggressive than pool rates and drive real mechanical room space, pump sizing and chemical storage decisions. The OBC governs the constructed system while O. Reg. 565 sets the operating water quality standards public health will test against, so design the treatment train to make those operating targets achievable. Common pitfalls include undersized filtration for actual bather loads, missing backflow prevention on the fill line, and no practical way to fully drain the basin for cleaning.

Plain language

Hot tub water gets dirty quickly because it is hot and crowded, so a public spa must constantly pump its water through filters and disinfection equipment. The system has to be big enough to keep the water clean even on busy days.

Related questions

What counts as a public spa or hot tub under the Ontario Building Code?What safety features does a public spa need under the Ontario Building Code?What emergency provisions must a public spa have in Ontario?

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This page is provided for general information. Building code requirements depend on your specific project, occupancy and municipality, and code editions change. Always verify requirements against the current Ontario Building Code and confirm with your local building department.