Ontario · CSA Z769 / O. Reg. 153/04

Phase 2 Environmental Site Assessment

Intrusive sampling to confirm or rule out the contamination flagged by a Phase 1 — boreholes, monitoring wells and laboratory testing, reported against the standard your transaction or filing needs.

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Frameworks: CSA Z769 or O. Reg. 153/04chosen to match the purpose
Method: Boreholes & monitoring wellssoil and groundwater sampling
Follows: A Phase 1 ESAwhere a concern has been identified
Typical use: RSC filing & permitsas well as transactions

What a Phase 2 ESA is

Two frameworks apply in Ontario, chosen according to what the result is for.

One follows the Canadian Standards Association's CSA Z769, typically used for real estate transactions and due diligence. The other follows Ontario's O. Reg. 153/04, as amended, typically used for rezoning, filing a Record of Site Condition, and municipal or provincial applications such as building permits.

A Phase 2 is generally conducted after a Phase 1 has identified potential Areas of Potential Environmental Concern. The aim is to determine whether contamination is actually present and, if so, its nature and extent.

A Phase 2 is often required where the site or an adjacent property has involved potentially contaminating activity — dry cleaning, auto repair, manufacturing, gas stations or scrap yards — or where above or underground storage tanks are present or were historically present.

Unlike a Phase 1, a Phase 2 is intrusive: it involves on-site drilling and sampling, with results confirmed through laboratory testing rather than inferred from records and observation alone.

Activities that most often trigger a Phase 2

Where a Phase 1 review finds one of these in a site's history, a Phase 2 is the usual next step.

Dry cleaning

Auto repair

Manufacturing

Gas stations

Scrap yards

Storage tanks (AST/UST)

The Phase 2 ESA Process, Step by Step

Five stages, from work-plan design to final report — typically completed in 3–6 weeks depending on lab turnaround.

01 Work plan design Borehole and monitoring well locations are selected based on the Phase 1 findings, targeting suspected spill areas, former tank locations, and drainage points.

02 Drilling and sampling Boreholes are advanced to the target depth, with soil samples collected at multiple intervals and field-screened before selection for laboratory analysis.

03 Monitoring well installation Where groundwater is encountered, wells are installed to allow repeat sampling over time, since concentrations can vary seasonally.

04 Laboratory analysis Samples are sent to an accredited laboratory to test for the contaminants of concern identified in the Phase 1 — commonly petroleum hydrocarbons, VOCs, metals, or PCBs.

05 Report and comparison to standards Laboratory results are compared against applicable site condition standards for the property's actual and intended use, with any exceedances clearly flagged.

What a Phase 2 ESA Report Is Good For

A Phase 2 ESA report confirms or rules out contamination, and is relied on for:

Filing a Record of Site Condition An RSC filed with the Ministry of the Environment, Conservation and Parks generally requires a Phase 2 ESA confirming the site meets applicable standards for its intended use.

Rezoning and severance applications Municipalities often require confirmation of soil and groundwater conditions before approving a change in permitted land use.

Remediation planning and budgeting Where contamination is confirmed, the Phase 2 defines its extent and concentration, forming the basis for a remediation work plan and cost estimate.

Risk assessment and liability allocation In a real estate transaction, confirmed lab results let buyers and sellers negotiate price adjustments or environmental indemnities based on actual, not assumed, conditions.

Construction and excavation planning Knowing the depth and extent of any impacted soil in advance allows contractors to plan excavation, disposal, and import fill requirements accurately.

Lender and insurer conditions Where a Phase 1 identifies a Recognized Environmental Condition, lenders and insurers commonly make financing or coverage conditional on a completed Phase 2.

Related services

Environmental Site Assessment — Overview

Phase 2 ESAs by area

We work across Ontario, generally within 500 km of our Vaughan head office. Each area has its own page.

Common questions

Phase 2 ESA Questions

What triggers a Phase 2 ESA?

Most often a Phase 1 that identifies an Area of Potential Environmental Concern. It is also common where the site or an adjacent property has a history of potentially contaminating activity — dry cleaning, auto repair, manufacturing, gas stations, scrap yards — or where above or underground storage tanks are present.

What is the difference between the two Ontario frameworks?

CSA Z769 is the standard typically used for real estate transactions and general due diligence. O. Reg. 153/04, as amended, is used where the outcome feeds into rezoning, a Record of Site Condition filing, or a municipal or provincial application such as a building permit.

Does a Phase 2 involve digging or drilling?

Yes. Unlike a Phase 1, a Phase 2 is intrusive — boreholes and monitoring wells are placed at locations most likely to have been affected, and soil and groundwater samples are sent for laboratory analysis.

How is the sampling plan decided?

From the findings of the Phase 1: the location of former operations, storage areas and any documented spills or releases determines where boreholes and wells are placed.

What happens after the Phase 2?

If contamination is confirmed, the report characterises its extent and may recommend remediation, ongoing monitoring, or a risk assessment, depending on the intended use of the property.

Need a Phase 2 ESA?

Send us the property address and any Phase 1 findings — we'll confirm the sampling scope and reply with a fixed quote, usually within one business day.

Request a Quote or call 1-888-607-6556