Relocating plumbing under an existing slab

Moving an under-slab drain affects slope, slab, fill, soil-gas/radon membrane, future access and concrete restoration.

Decision triage

VERT / GREEN · JAUNE / YELLOW · ROUGE / RED

What the professional checks

The professional checks routing, drainage slope/venting, slab type, excavation/backfill, under-slab membrane, radon and concrete restoration.

Official sources

Sources checked: 2026-08-24

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
V16

Advanced diagnostics to cross-check

V16 connects water, soil, climate, safety, materials and seasonal use to existing projects.

Pyrite, pyrrhotite and ochre
V17

Specialized systems to cross-check

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

Irrigation 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
V34

Use, excavation and construction constraints

V34 connects use permits, soil, excavation, neighbouring structures and public-space logistics before hard-to-reverse work.

Post-tensioned slabs: drilling, anchoring and coring
V47

V47 interfaces not to miss

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

Joist notches/holesBuilding trap