Sewer gas, traps and plumbing vents

Diagnose odour through trap seals, venting, seldom-used drains, cleanouts and sumps instead of masking the smell.

VERT / GREEN

Identify seldom-used fixtures/drains and document where odour appears.

JAUNE / YELLOW

A lost trap seal, disturbed venting or non-airtight cover can allow gases indoors.

ROUGE / RED

Persistent strong odour, open drainage system, unsealed sump or gas-related symptoms: ventilate and obtain correction.

Interactive triage

Helps choose the next step; it does not replace design, permits or professional diagnosis.

Seldom-used drain
Check trap seal and why it dries out before using chemicals. Plumbing vent altered
Have venting checked; plumbing vents must not serve other systems. Sump cover not airtight
Correct sealing/venting for the sump function. Odour localized and cause documented
Record the correction and monitor recurrence.

Useful tools and data

Drain/trap/vent map
Odour log
Cleanout visual inspection

What the professional checks

Test trap seal/venting
Check drainage pressures
Confirm sump/vent compliance

Official sources

Checked 2026-08-22.

Related path

Continue with the right tools

These links connect this page to the next useful checks and decisions without repeating the full content.

Start from a symptomOrganize plausible causes, observations, urgency and the right professional.Open →Track water useCompare meter readings and flag unusual changes.Open →Review water resilienceConnect flooding, drainage and future events to building adaptations.Open →Score home resiliencePrioritize water, outages, fire, climate, health and records.Open →Plan site, drainage and utilitiesCoordinate access, water, sewer, wells, septic, grading and site constraints.Open →

V14

Systems to check before closing the work

V14 connects envelope, air, fire, structure, water and code instead of treating each project in isolation.

Renovation dependenciesPlumbing pressure and systemHidden services before drillingCode versions

V15

Remaining system checks not to miss

V15 covers issues that can block a project, cause a loss or become expensive once concealed.

Before closing wallsPrivate sewer/water servicePost-renovation commissioningCodes + climate by province

V17

Specialized systems to cross-check

V17 completes gas, soil, water, fire, climate and structural interfaces.

Gas and combustionIrrigation and backflow

V19

Edge systems to integrate into the project

V19 covers interfaces that become important when multiple home systems interact.

Pipe freeze protectionDrain-water heat recovery

V26

Often-overlooked service interfaces

V26 connects systems that cross utility, plumbing, HVAC, envelope and metering boundaries.

Domestic hot-water recirculationWater pressure, PRV and thermal expansion

V28

Finish and service details to verify

V28 connects small details that become costly once finishes are closed.

Kitchen island/peninsula services and supportPlumbing cleanouts and service access

V29

Household safety and compliance details

V29 connects smaller risks that often fall between finishes, appliances, plumbing and local code.

Floor drain trap seals and primers

V31

Commissioning and everyday safety

V31 helps verify systems after work and document the values that make a home safer to operate.

Gas-to-induction cooking conversionPlumbing vents: frost, snow and roof termination

V32

Post-disaster and legacy systems

V32 connects contamination, storm damage, legacy materials and recommissioning before rebuilding.

Sewage backup: contamination and recoveryStorm/tree impact: structure, re-entry and stabilization

V47

V47 interfaces not to miss

These details are small on a drawing but can control water, structure or durability.

Joist notches/holesBuilding trapCast-iron stack