Markham, ON onsite wastewater guide

Septic systems in Markham: permits, records, inspections and property checks

Confirm how the exact property is serviced before applying any septic advice. Utility, tax, permit and approval records are more reliable than lot size or neighbourhood appearance. One street can contain different servicing histories, so establish sewer versus onsite service for the specific parcel first.

First questionSewer or onsite?
Local lensGreater Toronto Area
Before buyingRecords + condition
Before workLocation + capacity

First, confirm this property’s wastewater service

A city-area guide cannot tell whether a specific parcel is connected to sewer or has an onsite system.

Local septic / permit route

Use the local authority route below for septic approvals, permits or records. Confirm sewer connection separately with the municipality or utility.

Open local septic / permit page →

Onsite system confirmed

Find the parcel’s system approvals and verify current rules with the responsible local authority before work.

Start with provincial guidance →

Service unknown

Check utility bills and permit records; ask the local authority to confirm current service before planning an onsite inspection or repair.

How to confirm service →
Provincial rule: In Ontario, most onsite sewage systems with design capacity at or below 10,000 litres per day are regulated under the Building Code Act. Permits are typically issued by the local municipality or, in some areas, a health unit; larger systems may require provincial environmental approval. Open provincial / regional onsite-wastewater authority →

Markham’s ePLAN and installer information

Markham’s building-permit guide identifies Schedule 2, Sewage System Installer Information, for projects with private onsite sewage systems. The guide also points applicants to ePLAN for electronic submissions. If a seller provides a drawing but no installer or approval record, ask Building Services what the property file contains; the drawing may describe a proposal rather than the system that was finally installed.

For a home expansion, the practical question is whether the existing private system was designed for the new wastewater load and whether construction will intrude on the treatment or replacement area. Have the designer put that answer into the permit package, along with the correct Schedule 2 details where applicable. The Markham guide is a document checklist, not a parcel-specific statement that the lot is on septic. Check water/sewer service records first, then ask the City which system drawings and site evaluation it requires for the actual work.

Markham — guide to building permits →

Markham’s current building-permit guide lists onsite sewage system drawings and details plus a Statement of Design for properties served by a private system. It also identifies Schedule 2 installer information for applicable private onsite projects. For additions and secondary-unit work, this means the wastewater system is not just a note in the margin: the private-system design belongs in the coordinated permit package and should be checked against the proposed building footprint and use.

Markham expects the onsite design to appear in the building package

Who approves septic work around Markham?

Ontario regulates most residential onsite sewage systems under Part 8 of the Building Code. Systems with a daily design flow of 10,000 litres or less are generally administered by a municipality, health unit or conservation authority; larger systems fall under the environmental approval regime.

Confirm the exact Part 8 authority before applying. New systems, replacements, major repairs, additions or changes that increase design flow can require permit review, site/soil information, design calculations and inspections before covering.

Local approval route: Markham’s permit guide names Schedule 2 for private onsite sewage work and uses ePLAN. Confirm both the service type and the submitted system design for the property.

Official sources for this guide

If sewage is backing up or surfacing, stop using affected fixtures and contact a qualified professional or the responsible authority. Never enter a septic tank.

Start with these official sources

Last verified: September 28, 2026. Local and provincial/regional source routes checked. Confirm the parcel’s service status, responsible authority and current requirements before work. How we research these guides →