Plumbing Inspection Checklist for an Ontario House: Underground Before the Pour, Rough-In Before Insulation, the Water Test, Final and Before the Last Payment

Plumbing & Water

The Plumbing Checklist: Four Stops, and the Expensive One Is Under the Concrete

The municipal inspector checks the plumbing against the Code. This list is for you, the person paying for it and living with it. It is shorter than the inspector’s and aimed at different things: what you will want to know in ten years, what is cheap now and dear later, and what to have in your hand before the last cheque. Take it to the site at each stage, walk it with your plumber, and take a lot of photos.

A homeowner’s checklist for Ontario houses, checked October 2026. Prices are October 2026 ranges before HST; the core drill figure is our allowance, not a published price.

Stop One: Underground, Before the Pour

The building sewer, the water service and the under-slab plumbing are inspected before backfill and before the basement floor is poured. That is the inspector’s stop. Yours is the same afternoon, because after the pour, a forgotten drain is a jackhammer.

  • Every floor drain where the plans show it, including near the water heater and any softener, which needs somewhere to send its backwash.
  • The sump pit in the right corner, with room to service it.
  • A capped rough-in for a future basement bathroom, if there is any chance you will want one: toilet, shower and sink stubs, and the vent.
  • The water service or well line coming in where the mechanical room will be, not where it was easiest to dig.
  • Photos of all of it with a tape measure in the shot, taken from a fixed corner.

In our houses this stop is bigger than usual. We build ICF houses with hydronic radiant floors, and the radiant tubing is tied down before the slab is poured, so the drains, the sump pit and any future rough-in have to be placed, inspected and protected before the pour too. ICF exterior walls are concrete, so the water service or well line, the sewer or septic outlet, the hose bibs, the dryer vent, the water heater or boiler vent and the sump discharge each need a sleeve in the form first. We walk the house with the trades before the pour with a list of every penetration; the plumbing an ICF house page has that list.

What a Missed Item Costs Later

Missed at the right stageFix laterCost, before HST
A sleeve through an ICF or poured wallCore drill, patch and seal$150 to $400 a hole, allowance
Basement bathroom stubs under the slabBreak the slab and tie into the drainadds $1,500 to $8,000, $4,000 default
Drains below the sewer, no ejector plannedAdd a sewage ejectoradds $1,500 to $3,500
Sump pit, finished basementNew pit, cutting the slab$2,500 to $4,500
Backwater valve, finished basementInterior retrofit through the slab$1,000 to $3,500
A pipe moved after drywallDrywall access and repair$500 to $2,000, often more for plaster

October 2026 prices from published Ontario contractor pages and Canadian price guides. The core drill figure is our allowance.

Why Ontario prices are all over the map: the contractors and price guides we checked for adding a basement bathroom later did not agree on much. A GTA renovation contractor said $3,000 to $6,000 to rough in a 3-piece. A Toronto plumber said $3,500 to $14,000. A renovation cost guide said $4,000 to $8,000 for a half-bath. The gap is almost all underground: whether stubs were left under the slab, how much concrete has to come up, and whether the drains sit low enough to need an ejector. Budget $4,500 with stubs and $4,000 more without, and get two or three quotes on the same written scope.

Do the arithmetic on the one people skip. Adding a 3-piece basement bathroom later with stubs already in the slab is about $4,500 at the default. Without them it is $4,500 + $4,000 = $8,500. Two forgotten sleeves at the middle of our allowance are 2 x $275 = $550. Five minutes at stop one is worth more than any other five minutes on the job. The full numbers are on the bathroom rough-in cost page.

Stop Two: Rough-In, Before Insulation

The drain, waste and vent piping is water-tested to the roof line before the walls and ceilings are covered. Nothing gets covered before inspection, which means the insulator waits for the plumber, not the other way round. Your list:

  • Every fixture where the drawings say, at the height the vanity and the tub need. Measure a couple.
  • Supply pipes kept out of exterior walls where possible, which is the usual rule in any Ontario house.
  • Shower and tub valves that are pressure-balanced or thermostatic; the Code caps the water to shower heads and tubs at 49 C under Article 7.2.10.7.
  • Blocking for grab bars, a wall-hung toilet or a heavy vanity, while the studs are bare.
  • Shut-off valves where you can reach them, and the main shut-off where you will find it in the dark.
  • Photos of every wall and ceiling before drywall, with the tape in the shot. Ten years from now, this is how you hang a cabinet without hitting a pipe.

The rest of the before-drywall walk, the wiring and the framing, is on the before-drywall checklist. What the inspector is looking for is on the plumbing basics page.

Stop Three: Final, Before You Move In

The fixtures are inspected before use and before occupancy. Before that visit, walk it yourself:

  1. Run every tap and flush every toilet. Look under every sink with a flashlight five minutes later. Dry is the only acceptable answer.
  2. Label the shut-offs. Main, water heater, each bathroom, the outside taps, the softener bypass. A tag with a word on it, not a guess.
  3. The water heater has its T&P relief valve and discharge pipe in place, and nobody has capped, plugged or “fixed” either. A gas water heater is TSSA work by a registered gas contractor, not a plumbing item you check with a wrench.
  4. The sump has a water- and air-tight cover (Article 7.4.6.3), and the discharge goes outside, not into the sanitary sewer, a floor drain or the laundry tub.
  5. The backwater valve, if there is one, is the normally open type and you can reach its access cover. Ask the plumber to show you how to check it.

On a well, the first bacteria test happens here, before anyone drinks from it. Public Health Ontario tests for total coliforms and E. coli for free; the bottle has to reach the lab within 48 hours. If E. coli comes back, do not drink the water: boil it or use another source until the well is fixed and two clean tests in a row come back. The well water testing page explains the results.

Stop Four: Before the Last Payment

  • The final plumbing inspection passed, in writing, not “he said it was fine”.
  • Your well record, if a well was built: the contractor gives you a copy within 14 days and files it with the ministry within 30. Keep it with the deed.
  • Manuals and warranty cards for the water heater, pump, pressure tank, softener, UV and any filters, with the model numbers and filter sizes written on the front.
  • Your rough-in photos, in a folder you will find again.
  • The plumber’s warranty, in writing, with the start date.
  • The holdback kept until the lien period runs out, where the Construction Act applies.

The whole-house version of this stop is the final walkthrough checklist. On the houses we build on ICFhome.ca, the plumbing is done by licensed plumbers we hire and wells by licensed well contractors. Whoever builds your house, ask for the folder of paper from both.

Questions people ask

When is the plumbing inspected on a new house?

Before the sewer and water service are backfilled, before the under-slab plumbing is buried and the floor poured, at rough-in before the walls and ceilings are covered, and at the fixtures before you move in. Book each about 2 business days ahead.

Can I insulate before the plumbing inspection?

No. The drain, waste and vent piping is water-tested and inspected before walls and ceilings are covered. Insulate early and it may come back out.

What should I photograph before drywall?

Every wall and ceiling with plumbing in it, with a tape measure in the shot and a reference corner, plus the under-slab drains before the pour. They save you a hole in the wall later.

What is the maximum hot water temperature at a shower?

The Code caps it at 49 C under Article 7.2.10.7, with a pressure-balanced or thermostatic valve on showers and tubs.

What paperwork should I get from the plumber at the end?

The passed final inspection, the warranty in writing, the equipment manuals, and on a new well the well record, which the contractor must give you within 14 days.

Put the extras on the plan before stop one

The plumbing cost estimator prices the house by fixture, municipal or well and septic, basement or slab, so the plumbing is on paper before the concrete truck shows up. If you have quotes, the $99 review reads up to three and tells you which of these lines each one left out.

Price my plumbingReview my quotes, $99

Sources and further reading