The one decision that sets the price
Whether the plumbing moves. Everything else is secondary. The City of Ottawa requires a building permit for alterations, additions or extensions to a plumbing system, and states the exception plainly: replacing existing fixtures. It separately requires a permit for adding or removing walls, and separately lists replacing kitchen or bathroom cabinets as exempt provided plumbing fixtures remain in the same location.
So a bathroom where the toilet, tub and basin stay exactly where they are, with new fixtures, new tile and a new vanity, is a finishes job. A bathroom where the toilet shifts half a metre is a permitted construction project with inspections, a longer schedule and floor work. The gap between those two things in an Ottawa bathroom is commonly $8,000 to $15,000.
That is worth knowing before you fall in love with a layout. Sometimes moving the plumbing is clearly right, and a cramped 1960s bathroom with three fixtures in a line is a good example. Sometimes the same visual result can be had by keeping the drains and changing what sits on them.
Indicative Ottawa ranges for 2026
No public authority publishes trade pricing for this city, so these are indicative market ranges rather than sourced figures. Use them to tell a plausible quote from an implausible one.
Powder room, complete: $8,000 to $15,000. Standard main bathroom, gutted and rebuilt, mid-range finishes, layout unchanged: $18,000 to $30,000. The same room with plumbing relocated, a custom tiled shower and better finishes: $30,000 to $55,000.
Individual elements, where you want to price a partial job: a tub-to-shower conversion with a pre-formed base and the drain unchanged, $7,000 to $12,000, rising to $12,000 to $22,000 fully tiled with frameless glass. Tiling labour, $80 to $160 per square metre for standard format and $160 to $260 for large format or mosaic. A complete shower waterproofing system, $1,500 to $3,500.
A basement bathroom is its own category, because the drainage method dominates: $12,000 to $20,000 with a macerating system, $20,000 to $35,000 with an ejector pit, $25,000 to $45,000 breaking the slab for gravity drainage.
Why the age of the house changes the number
A bathroom demolition is a survey you pay for. In a 2005 Barrhaven ensuite there is usually nothing behind the tile but drywall and PEX. In a 1955 Alta Vista bungalow the same demolition commonly finds a steel tub set in mortar, cast iron drainage, galvanised supply piping narrowed by internal corrosion, no ground-fault protection, no exhaust fan, and green board or plaster where a waterproofing membrane should be.
None of that is a contractor inflating a bill. Replacing a galvanised supply run while the wall is open is the cheapest it will ever be, and leaving it in is deferring a leak. The problem is that none of it can be priced accurately before the wall comes off.
The answer is a written contingency allowance with rules attached: how much, what it may be spent on, who authorises a draw, and what happens to the unspent balance. Ten to fifteen per cent is realistic on a house built before 1980, and fifteen to twenty before 1950. A contractor who refuses a contingency and insists the fixed price covers everything is either padding heavily or setting up a change-order argument.
What a quote should contain
Six things, in writing. The scope line by line, including what is being removed and disposed of. Who holds the permit and who books the inspections. Which trades are doing which work, and the plumber's 306A certificate and the electrical contractor's ECRA/ESA number, because plumber is a compulsory trade in Ontario and hired electrical work must be done by a Licensed Electrical Contractor.
Then: the waterproofing system by manufacturer and product name, with a commitment to flood test the pan. A payment schedule tied to milestones rather than dates, because a schedule tied to dates pays for time rather than progress. And the warranty, with its length and its exclusions.
Ask all three bidders for a WSIB clearance certificate and a current certificate of liability insurance. Both are free to produce. WSIB coverage has been compulsory for most independent operators and sole proprietors in construction since 5 December 2024, with a narrow exemption for work on an existing private residence contracted directly by the occupant, and that exemption is worth understanding rather than being told about after an injury.
Where people overspend and underspend
Overspending usually happens on tile, on a freestanding tub in a room too small for it, and on a curbless shower entry bought for appearance rather than access. Tile material can be $30 or $250 per square metre, and in a 4.5 square metre bathroom the difference in total cost is smaller than people fear, but the difference in installation labour between a standard format and a large-format or herringbone layout is real and is charged separately.
Underspending happens in the places nobody sees, and it is the more expensive mistake. A properly sized and properly ducted exhaust fan. A complete waterproofing system from one manufacturer rather than mixed components. Blocking in the walls for grab bars while they are open, at a couple of hundred dollars. Replacing galvanised supply piping. An uncoupling membrane under floor tile, which matters in a city where much of the housing sits on seasonally moving marine clay.
If the budget has to be cut, cut the finishes and keep the assembly. Tile can be changed in fifteen years. A failed shower pan takes the ceiling below it with it.