Why it matters
The enclosure is drowning prevention and bylaw compliance; gaps, climbable fencing, or a gate that doesn't self-close are the first thing to fix with kids around. On the equipment side, vinyl liners last roughly 10 to 15 years and a pool that sat closed for seasons can hide liner and structure failure, "just needs a liner" often means "needs a liner and everything the dead liner let happen." Keep-fix-or-fill is a five-figure decision.
How to spot it
Photograph the enclosure and gate (does it close and latch itself?), the equipment pad (rust, age), and the water. Ask: pool age, liner age, last season it ran, and whether there's an enclosure permit. Heaved coping/deck around an inground pool suggests freeze-thaw movement.
What it costs
A compliant pool fence runs $45 to $85 a linear foot installed and code-compliant gates $600 to $900 each, with a flat $215 building permit in Toronto. Replacing an inground liner is $3,500 to $10,000 and up. Running the pool costs $1,000 to $1,500 a year unheated and $1,500 to $3,000 heated, covering chemicals, electricity, opening and closing. Getting rid of it is the number most buyers never think about: $11,000 to $20,000 to fill one in partially, and $20,000 to $70,000 to take it out completely depending on whether the shell is vinyl or concrete, plus $1,500 to $2,000 in permits.
What to do
Measure the enclosure against the local bylaw before you offer, because bringing one up to standard is your cost the day you close. In Toronto that means any pool where the water can exceed 600 mm deep needs a 1.2 metre enclosure, no climbable element between 100 mm and 1.2 metres above grade, and a self-closing gate with a lockable self-latching device. A hot tub is exempt only if it has a permanently attached structural cover that is fastened and locked. Tell your insurer the pool exists and ask about your liability limit, because a pool is treated as an attractive nuisance and the owner can be liable even to a trespasser. Ask what it costs to run and what it would cost to remove, and price both before you decide you want it.
Education and triage, not a home inspection. Enclosure rules are municipal bylaws that vary, Casaroo flags what's visible and points you to your municipality's requirements; a pool professional assesses the equipment.