Basement Bathrooms in Aurora

Every basement bathroom starts with the underground drain setup

Whether you are finishing a lower level in Bayview Northeast or Bayview Wellington for family and overnight guests, or adding a second full bathroom to a 1960s Regency Acres or Aurora Village bungalow for a secondary suite, every basement bathroom quote starts with what sits beneath the concrete floor slab.

Across Aurora, basement plumbing falls into one of three situations:

• An existing 3-piece builder rough-in in the right location. Most detached homes and townhomes built in Bayview Northeast, Bayview Wellington, Bayview Southeast and Aurora Grove since the late 1990s have three capped ABS pipes stubbed up through the concrete floor for a future toilet, shower and vanity, plus a capped vent line in the joists above. We uncap and test the stubs, check the vent tie-in, and verify that the pipe spacing fits your planned wall framing.
• A builder rough-in that needs to be shifted. Production builders frequently stub basement drain pipes awkwardly close to the stairs, furnace or water meter. When the toilet flange or shower trap sits a foot off from where the room needs to be framed, we saw-cut a neat channel in the concrete slab, shift the ABS drain and P-trap to the proper spot, have the underground work inspected, and pour fresh concrete before framing.
• No existing rough-in under the slab. In older Aurora bungalows, split-levels and mature Aurora Highlands houses, there are often no future drain stubs in the floor. We locate the main building drain under the slab, saw-cut a trench to tie in new 3-inch and 2-inch ABS branches (and a backwater valve where required), or—where the main sewer exits higher up the foundation wall—install a sealed sewage-ejector basin that pumps waste up into the main stack.

Six stages of building a basement bathroom

1. Headroom check, layout and permit drawings. We measure ceiling joists, steel beams, ductwork and cleanouts, then prepare scaled PDF floor plans showing fixture clearances and plumbing connections.
2. Concrete trenching and underground drains. Any slab saw-cutting, P-trap and backwater valve installation, municipal underground plumbing inspection, and concrete patching happen first. Because we are already working in a concrete slab, forming a recessed pan for a step-free curbless walk-in shower is often simpler in a basement than on a wood-framed second floor.
3. Moisture-protected framing and bulkheads. We frame walls with a sill gasket against the concrete slab, box cleanly around low HVAC ducts or shut-off valves with removable access panels, and install solid wood blocking for the vanity, shower glass and grab bars.
4. Water supply lines, venting and ESA electrical. PEX supply lines, proper plumbing vents, GFCI receptacles, mirror lighting, slim LED pot lights and optional electric radiant floor heating are installed and inspected.
5. Insulated exterior exhaust ducting. We run a dedicated insulated exhaust duct out through the rim joist to an exterior wall hood—never venting humid bathroom air into the basement ceiling joists.
6. Continuous waterproofing, porcelain tile and fixtures. The shower enclosure receives a continuous bonded waterproofing membrane before porcelain tile, the vanity, the toilet and custom tempered glass are installed. Read our 5-step renovation process.

Keeping a below-grade bathroom warm, dry and bright

Basements behave differently from upstairs bedrooms. Concrete slabs stay cool through the summer, which encourages condensation when warm, humid air hits cold surfaces. To keep a lower-level bathroom dry and comfortable year-round:

• We verify the foundation wall behind the bathroom is completely dry before framing; if you have an existing basement bathroom with musty drywall or loose tile, visit our bathroom repairs in Aurora page.
• We build the shower with waterproof foam backer board and a continuous membrane rather than standard drywall, paired with an uncoupling membrane (and optional electric in-floor heat) over the concrete slab.
• Where steel beams or furnace trunks drop the ceiling height, we place the shower head and vanity mirror in the full-height joist bay and tuck the toilet or linen storage under the bulkhead. For compact vanity and toilet dimensions that work in tight lower-level rooms, visit our small and condo bathrooms page.

Town of Aurora permits for basement bathrooms

Under the Town of Aurora Building Division’s guidelines, finishing a basement without structural changes or new plumbing does not always require a building permit, but adding or altering plumbing drains and vents for a new basement bathroom requires a plumbing and building permit—and registering a second or third dwelling unit carries its own Town of Aurora application and Ontario Building Code fire-separation, egress and ceiling-height requirements.

Source: Town of Aurora: Second or Third Dwelling Unit Registration & Basement Permits (accessed November 7, 2026)

Underground drain trenches must be inspected by the Town’s inspector before concrete is poured back over the pipe. Read our complete article on Aurora bathroom renovation permits for how electronic submissions through the CityView Portal (cvportal.aurora.ca) and inspections work.

What a basement bathroom costs in Aurora

When a basement bathroom connects cleanly to an existing builder rough-in without cutting the concrete slab, the installation labour matches an upstairs bathroom of the same size: our 7 x 9 ft labour package starts at $8,000, while a larger wet-room or relocated-rough-in layout aligns with our $15,000 package.

Concrete trenching, a sewage-ejector pump (if required), finish materials and the municipal permit fee are listed on separate lines in your written quote so there are no surprises. Check full all-in ranges and trade line items on our Aurora bathroom renovation cost page.

Send photos of your basement space for a written quote

Take two or three photos of your basement corner—showing the floor (and any capped rough-in pipes), the ceiling joists and ductwork above, and the nearby plumbing stack—and upload them on our free quote page. We will reply with an itemized written quote backed by our written labour warranty.