What is a rough-in plumbing inspection in New Brunswick and at what stage of the basement bathroom project does the inspector need to be called in Moncton?

A rough-in plumbing inspection is a mandatory review by a building inspector before any new plumbing work is covered up by walls, floors, or ceilings. In Moncton, this inspection must happen after all your drain lines, supply lines, and vent stacks are installed and pressure-tested — but before a single piece of drywall goes up or concrete is poured back over a slab opening.

What the Inspector Is Looking At

During a rough-in inspection for a basement bathroom in Moncton, the inspector is verifying that your plumber has installed everything to the NB Building Code and the National Plumbing Code of Canada. This includes the proper slope on drain lines (typically 1/4 inch per foot fall toward the main), correct pipe sizing for each fixture, proper venting to prevent sewer gas from entering the living space, and that the work connects correctly to your existing drain-waste-vent (DWV) system. They'll also confirm that a backwater valve is present or planned — this is strongly recommended for Moncton basements given the risk of municipal sewer backup during heavy spring rains and snowmelt events.

If your bathroom requires breaking the concrete slab to tie into the main drain below the floor — which is almost always the case for a basement toilet — the inspector needs to see all of that below-slab work while it is still open and exposed. Once the concrete is poured back, there is no way to verify what's underneath without jackhammering it out again. This is the single most common and costly mistake homeowners make: pouring the slab back before calling for inspection.

The Exact Sequence for Moncton

Moncton has its own building inspection department through the City of Moncton, which means faster turnaround than rural RSC areas — typically 1 to 3 business days for an inspection appointment once you call. Your sequence should look like this: pull your plumbing permit first, have your licensed plumber complete all rough-in work including below-slab drains and above-slab supply and vent lines, call the City of Moncton building department to book the rough-in inspection, pass inspection, then pour concrete over the slab opening and proceed with framing and drywall. Your plumber should also be present or available during the inspection to answer any deficiency questions on the spot.

The same logic applies to your electrical rough-in — that inspection also must happen before walls are closed. Many homeowners coordinate both inspections close together to avoid holding up the project.

Practical Tips

Never let a contractor talk you into skipping or rushing past the rough-in inspection to stay on schedule. If you close walls before inspection, the inspector can and will order you to open them back up — at your expense. Keep your permit posted on site and make sure your plumber pulls the permit in their name, as licensed tradespeople are responsible for the work passing inspection in NB.

A full basement bathroom rough-in in Moncton typically runs $3,000–$8,000 depending on how far the new fixtures are from your existing drain stack and whether slab cutting is involved.

If you're planning a basement bathroom and need a licensed plumber or a contractor to manage the full project, New Brunswick Basements can match you with local renovators through the New Brunswick Construction Network — free of charge. You can also find plumbing and electrical trades at newbrunswickconstructionnetwork.com.