Last Revision:
August 1996

Statement of principles (1.0)

This guideline describes the position and requirements of the Ministry of Environment and Energy (MOEE) regarding the assessment of the potential impact on groundwater caused by proposed developments on individual on-site sewage systems (sub-surface sewage systems). This guideline applies only to those areas of the Province which have not been designated under Notice 3/87 (attached) as subject to MOEE Guideline B-7, Incorporation of The Reasonable Use Concept into MOEE Groundwater Management Activities (formerly MOEE Policy 15-08). In areas so designated, the proposed development must comply with the requirements of MOEE Guideline B-7and its associated guidelines.

The guideline reflects the Ministry’s experience with development utilising individual on-site sewage systems, and emphasises the need to minimise the potential for adverse groundwater impacts resulting from their use.

This guideline is presented with the understanding that the use of individual on-site sewage systems has been justified by the municipality or the local planning authority. This justification includes an evaluation of alternative types of servicing. The Province encourages municipalities to plan for environmentally appropriate servicing infrastructures by undertaking comprehensive, large-scale assessment of groundwater and surface water resources (see the Provincial Policy Statement).

The purpose of this guideline is to protect the environment and public health by ensuring that development utilising individual onsite sewage systems proceeds at a density and scale which will not result in, or cause degradation of, groundwater resources in exceedance of acceptable limits. Compliance with acceptable limits shall be demonstrated through a prediction of the development’s nitrate impact on the groundwater at the development boundary. The Guideline is intended to encourage the assessment of the potential for degradation on the basis of a technically based and technically defensible evaluation of the proposal.

Objectives (2.0)

The objectives of this guideline are as follows:

  1. To provide technical guidance to professionals involved inland development (in particular, hydrogeologists) in assessing the potential for unacceptable groundwater impacts resulting from the use of individual on-site sewage systems, through a three stage assessment process.
  2. To ensure that proposals are submitted with the required technical support to allow the Director to either support the proposed development, designate the proposed development under Notice 3/87 (thus requiring an assessment in compliance with MOEE Guideline B-7 and its associated guidelines), or to recommend against approval.

Application of the guideline (3.0)

This guideline applies to the combined or total impact on groundwater of a development proposal of more than five units with individual on-site sewage systems, in areas which have not been designated under Notice 3/87 (attached). The Guideline applies to residential, commercial and industrial proposals which use individual on-site sewage disposal systems for the treatment of domestic waste. Application to development proposals involving five or fewer units shall be at the discretion of the Regional Director. Although MOEE does not normally review development proposals consisting of 5 or fewer lots, municipalities are encouraged to retain, on their behalf, professionals with demonstrated expertise in hydrogeology with emphasis on development on private services, to review studies prepared in accordance with this Guideline. Municipalities are also encouraged to implement the provisions of this guideline in their consideration of developments by consent or severance.

This guideline does not apply to the following:

  1. Large Subsurface Sewage Disposal Systems as defined in Notice 3/87 (attached);
  2. the assessment of impacts of existing isolated individual residential sewage systems or interference between individual home systems on existing neighbouring lots within a subdivision (see Note below);
  3. applications for approval of on-site systems which are replacements due to the failure (e.g., due to hydraulic load, age, etc.) of the original system.

This guideline may not apply to non-standard individual on-site systems which are specifically designed to reduce nitrate loadings. It should be emphasised that MOEE encourages the development of new technologies for the treatment of domestic sewage waste. The Ministry will entertain proposals for development which incorporate new technologies. Contact your regional MOEE office for information on these types of systems.

Note: Where the use of individual on-site systems has resulted in unacceptable impairment of off-site water quality, the issue should be handled in accordance with MOEE Guideline B-9-1 (formerly Policy 15-10), Resolution of Groundwater Quality Interference Problems.

Designated areas under notice 3/87 (4.0)

Under Notice 3/87, the Director under Part VIII of the Environmental Protection Act or the MOEE Regional Director may designate a municipality or an area of a municipality as subject to MOEE Guideline B-7.

It is important to note that even though an applicant may meet the requirements of Section 5 of this Guideline, the Director reserves the right to require more detailed assessment or to designate any site or area of a municipality as subject to MOEE Guideline B-7 under Notice 3/87. The likelihood of this occurring is greater where:

  1. conditions outlined in Section 5.1 are not met;
  2. the development proposed has a higher density than previous development proposals in the municipality;
  3. the scale of the proposal is such that an increased degree of assurance is appropriate; or
  4. it is known that there are existing high levels of groundwater contamination by nitrate-nitrogen.

When these environments are encountered or these developments are proposed, the Director’s support may be conditional upon the establishment of monitoring programs and financial assurances. Under these circumstances contact the local MOEE Regional Office for more information.

Although the Director may support a proposal involving individual on-site sewage systems and permit their installation, the Director does not assume responsibility for failure of the system(s), for correcting the damage to adjacent properties, or for the construction of new sewage systems. This is the responsibility of the proponent/owner of the system.

Groundwater impact assessment in non-designated areas (5.0)

General Evaluation (5.1)

The groundwater impact assessment will address the ability of the lands, identified by and restricted to the development proposal document, to treat sewage effluent to meet acceptable limits. This assessment1, and the assessment described in the "Technical Guideline for Private Wells: Water Supply Assessment", should be completed and submitted together as one document. Approval Authorities (i.e. the Ministry of Municipal Affairs and/or designate) should only consider support for development applications involving individual on-site sewage systems where the proponent and/or the consultant has:

  1. in conjunction with the municipality, defended the use of private services to the satisfaction of the MOEE Regional Director in accordance with the Provincial Comprehensive Set of Policy Statements, particularly, the Policy Statement and Implementation Guideline B7, Planning for Sewage and Water Services, and the Policy Statements and Implementation Guidelines B8 through B11, Growth and Settlement;
  2. demonstrated to the local Health Unit (or to the MOEE, in those areas where MOEE administers the Part VIII Program) that the site complies with the requirements of Ontario Regulation 358 and related policies and guidelines;
  3. determined the representative existing background nitrate nitrogen levels in the receiving groundwater. This determination will involve the collection of groundwater samples from various locations on and adjacent to the development site. The consultant must provide a clear rationale for the number of times the site is sampled, the period of time over which the sampling has been undertaken(capturing seasonal variations), and the manner in which this information is used in the assessment. The consultant must discuss the existing background nitrate-nitrogen concentrations relative to nitrate sources, and the susceptibility of groundwater to contamination. The Ministry will normally not support development in areas where background nitrate-nitrogen concentrations exceed 10mg/L. Where nitrate concentrations between 0 and 10 mg/L are found, the MOEE may also decide not to support development if the proponent’s consultant cannot provide a reasonable explanation for the existing levels of nitrate concentration in the groundwater. However, if it can be demonstrated that existing levels of nitrates are the result of historical agricultural practices on the site (for example farming, feedlot, etc.), the proponent may be able to argue that the nitrate levels will decline after development, and;
  4. demonstrated that the area is not obviously hydrogeologically sensitive (for example, karstic areas, areas of fractured bedrock exposed at surface, areas of thin soil cover, or areas of highly permeable soils).

It is not the intent of MOEE to promote the development of areas with high infiltration rates (for example, sandy overburden deposits). Due to lack of effective effluent treatment, proposed development on individual on-site systems should not be approved in soils which have high infiltration rates.

Three-Step Assessment Process (5.2)

Every proposed development involving individual on-site sewage systems requires an assessment of the groundwater impact potential. The purpose of the assessment is to ensure that the combined effluent discharges from all the individual on-site sewage systems in a development will have a minimal effect on the groundwater and the present or potential use of the adjacent property. For the purposes of this Guideline, the Ontario Drinking Water Objective (ODWO) of 10 mg/L of nitrate-nitrogen is used as an indicator of groundwater impact potential. This Guideline does not define a precise methodology for determining the expected level of impact; however, it does set out the major considerations which should be included in a defensible assessment of the impact potential.

The assessment involves a three step process. The need to advance to the next step depends on the conditions defined in the previous step. The process is dependent on first satisfying the general requirements defined in Sections 4.0 and 5.1.

The first step involves a definition of the proposed development’s minimum lot size. If the minimum lot size is smaller than that defined in Section 5.4, the assessment must progress to the second step, which involves evaluating the relationship between the individual on-site sewage systems and the groundwater. Where it cannot be demonstrated that the systems are isolated from existing or potential groundwater supplies, it will be necessary to progress to the final step of the assessment, which involves a detailed examination of contaminant loading to the groundwater.

Where a report is found to be incomplete, draft or preliminary, or makes unsubstantiated claims, the MOEE will advise the proponent by letter with regard to the report’s deficiencies. MOEE may not undertake a full review until such time that a complete report(i.e., one which satisfies the requirement of this Guideline) has been submitted.

Fundamental Considerations (5.3)

  1. For the purposes of this guideline, the only exceptions to the use of groundwater for anything other than a drinking water supply shall be:
    1. For reasonable uses which involve water quality more stringent than defined by the Ontario Drinking Water Objectives (for example: providing base flow to a cold water trout stream), or
    2. At the Director’s discretion.
  2. Groundwater impact predictions shall be calculated for the development site property boundary.
  3. The consultant must make recommendations regarding the optimum location and orientation of leaching beds. In general, the attenuative capabilities of a site can be optimised by maximising separation distances between individual on-site systems and downgradient wells and property boundaries.
  4. Where applicable, the impact of the on-site discharge of sewage effluent into surface water must be evaluated. This work must be done by qualified individuals and must address potential impact from phosphorus and other parameters which may be of concern (see MOEE Guideline B-1-1, Water Management -Policies, Guidelines, Provincial Water Quality Objectives of the Ministry of Environment and Energy, and contact your local Regional Office). The concentration of phosphate used in assessing the potential impact of sewage effluent should normally be 15 mg/L.

Step One: Lot Size Considerations (5.4)

For developments where the lot size for each private residence within the development is one hectare or larger, the risk that the boundary limits imposed by these guidelines may be exceeded by individual systems is considered acceptable in most cases. Developments consisting of lots which average 1 hectare (with no lot being smaller than 0.8 ha), may not require a detailed hydrogeological assessment, provided that it can be demonstrated that the area is not hydrogeologically sensitive. In such circumstances, it is the responsibility of the proponent to obtain a professional analysis from a qualified consultant that the area is not hydrogeologically sensitive.

It is assumed that attenuative processes within a one hectare lot will be sufficient to reduce the nitrate-nitrogen to an acceptable concentration in groundwater below adjacent properties. It should be noted that sufficient attenuative processes may not be present in hydrogeologically sensitive environments, or where there is little water surplus available2.

Step Two: System Isolation Considerations (5.5)

Where proposed lot sizes are less than one hectare, the proponent and/or the consultant is/are responsible for assessing the potential risk to groundwater. Developments will normally be considered as low risk where it can be demonstrated that sewage effluent is hydrogeologically isolated from existing or potential supply aquifer(s). In making this assessment, the proponent and/or the consultant must:

  1. evaluate the most probable groundwater receiver for sewage effluent: its definition must be defended by hydrogeological data and information obtained through a test pit, auger hole and/or test drilling program; and
  2. define the most probable lower hydraulic or physical boundary of the groundwater receiving the sewage effluent.

The consultant must clearly define those portions of the subsurface which will be affected by the effluent. Detailed predictions of the shape of individual contaminant plumes and a description of specific contaminant concentrations over space and time may not be required.

The potential for isolation must be assessed on a site specific basis and may involve assessments of geologic and/or hydraulic boundaries. Please note that this may require hydrogeologic assessment of lands up to 500 metres beyond the actual development boundary.

In some cases, it may be necessary to demonstrate isolation from sensitive surface water environments. Wherever there is a potential for surface water impact, the proponent should contact the MOEE Regional Surface Water staff.

When it has been demonstrated that the sewage effluent will not enter supply aquifers, the lot density of the proposed development may be dictated by factors such as the need for sewage system replacement areas (i.e., contingency area), and by the minimum distances between individual on-site beds and wells, as defined by Ontario Regulations 358 and 903.

Step Three: Contaminant Attenuation Considerations (5.6)

Where it cannot be demonstrated that the sewage effluent is hydrogeologically isolated from all existing or potential supply aquifers, a hydrogeologic study is required to assess the risk that the development’s individual on-site systems will cause concentrations of nitrate-nitrogen in groundwater to exceed 10 mg/L at the downgradient property boundary. As described below, there are various methods by which this detailed risk assessment can be done.

Monitoring-Based Assessments (5.6.1)

The Ministry recognises that groundwater, infiltrating precipitation and sewage effluent will not be completely mixed at the property boundary. It is also recognised that processes such as absorption, denitrification, filtration and biodegradation may attenuate contaminants as the effluent passes down through the unsaturated zone and moves into the saturated zone. Since these processes are extremely difficult to quantify with any accuracy, they are usually only considered as a safety factor. However, if the consultant can provide documentation to the satisfaction of MOEE regarding the presence and extent of these processes on-site, their impact on nitrate concentrations will be considered. As discussed below, there is a number of ways in which this can be done.

  1. Existing Development

    In some situations, there may be nearby on-site sewage system based development in a similar hydrogeological environment. If this development has been in place for a lengthy period of time, information on existing groundwater quality could be used to demonstrate the combined effect of all available attenuative processes. This empirical information may then be used to help predict the impact of the proposed development.

    The onus is on the proponent and/or the consultant to demonstrate adequately that:

    1. the existing and proposed developments are located in similar hydrogeological environments;
    2. sewage effluent (quantity and quality) from the existing and proposed developments are comparable;
    3. monitoring produces results which accurately represent water quality conditions beneath the existing development. The consultant must provide a clear rationale for the number of times the site is sampled, the period of time over which the sampling has been undertaken (capturing seasonal variations), and the rationale for the way in which this information is used in the assessment.

    In general, monitoring of groundwater quality should be concentrated close to the existing individual on-site systems. Due to effluent plumes possibly forming discrete, elongated shapes, intensive monitoring may be required to ensure that monitoring wells located further from the individual on-site systems are measuring effluent concentrations within the effluent plume(s). Water supply wells are not meant to be used as monitoring wells.

  2. Phased Development

    In situations where there is no existing development, it maybe possible to develop lands considered in the planning document in phases, beginning with the upgradient portion. Information obtained from monitoring effluent discharged from individual on-site systems in the upgradient phase, and its impact on groundwater, can then be used to determine the extent to which the downgradient portion of the site can be developed. Before approving such a phased development, the Ministry must be satisfied by the Ministry of Municipal affairs (MMA) or the delegated planning approval authority, that adequate planning controls are in place to regulate development of the downgradient portion of the site.

Predictive Assessment - Residential Development (5.6.2)

The Ministry requires the following considerations and assumptions to be used in assessing the combined impact of individual on-site sewage systems at the boundary of residential developments:

  1. Contaminant Source: In most cases total nitrogen (all species) converted to nitrate-nitrogen is considered as the critical contaminant. For the purposes of predicting the potential for groundwater impacts, a nitrate loading of at least 40 grams/lot/day per residential dwelling unit shall normally be used3.
  2. Contaminant Attenuation:
    1. In assessing contaminant attenuation, only dilution will be accepted by the Ministry as a quantifiable attenuation mechanism for nitrate.
    2. Dilution models involve dilution with infiltrating precipitation. Mixing with groundwater flowing through the site will normally not be allowed because it is usually not possible to control up gradient land uses. Flow through will not be considered where sensitive hydrogeological conditions exist. However, where upgradient lands have been fully developed for a considerable period of time, the quantity and quality of groundwater flow available to dilute the effluent entering the receiving groundwater may be considered.
    3. The amount of available moisture surplus should normally be obtained from Environment Canada. Where available, reliable, long-term, site specific information, obtained from detailed water balance and/or groundwater studies, can be used.
    4. Estimates of the amount of this surplus which infiltrates into the ground must be based on site specific factors such as soils, topography, surface geology, and impermeable areas (including roof tops and paved areas).
    5. The volume of sewage effluent, if used as dilution water in mass balance calculations, should not exceed 1000L/day/lot.
    6. Mathematical (computer) models may be used to assess the impact potential. Although the selection of model software will be left to the proponent, the Ministry must be provided with information on the model’s validation and how its limitations and assumptions affect the results. All model simulations must include appropriate sensitivity analyses.

    It is the intent of MOEE to allow only those dilution models to be used which are reasonable and can be defended on a site specific basis. Where the Ministry has concerns regarding the predicted impact, the Regional Director may consider designating the development under Notice 3/87.

Predictive Assessment - Industrial/Commercial Development (5.6.3)

This guideline only applies to developments which have an average daily flow of less than 4,500 L/day/lot. Developments with larger flows will be assessed according to MOEE Guideline B-7. In addition, the sewage assessed should consist of domestic wastes only. No industrial/commercial cooling or process wastewater is to be considered.

The nitrate loading from industrial/commercial individual on-site systems can vary greatly depending on the type and intensity of use. Since specific uses for each lot or block are not known at the planning document review stage, it is necessary to determine how much nitrate can be discharged from each individual on-site system without exceeding the ODWO of 10 mg/L at the property boundary. The following procedure is then used to set maximum allowable effluent flows for each lot:

  1. Available Infiltration:
    1. The amount of available moisture surplus should normally be obtained from Environment Canada. Where available, reliable, long-term, site specific information, obtained from detailed water balance and/or groundwater studies, can be used.
    2. Estimates of the amount of moisture surplus which infiltrates into the ground must be based on site specific factors such as soils, topography, surface geology, and impermeable areas (including roof tops and paved areas).
  2. Maximum Allowable Flow:

    The maximum allowable flow for each lot or block in the industrial/commercial development can be calculated by dividing the amount of available infiltration {from (a)} by a factor of three4.

  3. Maximum Number of Users:

    To determine the maximum number of users which can be supported by the calculated allowable flow, please refer to Appendices 9.3.1 and 9.3.2 of MOEE's "Manual of Policy, Procedures and Guidelines for On-Site Sewage Systems."Restrictions regarding the allowable number of users will normally be incorporated as recommendations in the consultant’s assessment, and the recommendations shall be implemented by provisions in the development agreement between the proponent and the municipality.

Additional Research (5.7)

The Ministry recognises that the assumptions required for allowing a predicted level of 10 mg/L to be used as a boundary target criterion, for exempting lots of one hectare, or for using nitrate nitrogen as the critical contaminant etc., may not be technically supported in every case. The Ministry recognises that as research continues, information and technologies may become available which warrant minor or substantial revisions to this guideline.

Implementation (6.0)

MOEE staff will implement this guideline through comments and advice supplied to municipalities, the public, and the approval Authority on planning documents circulated under the Planning Act.

For development applications (official plan amendments, plans of subdivision or condominium) involving more than five lots with individual on-site sewage systems, the approval Authority must ensure that an impact assessment has been completed in accordance with this Guideline which demonstrates that the impacts on ground and surface water of the proposal will be within acceptable limits. Shoreline development proposals will be reviewed on a case-by-case basis. The groundwater impact assessment must be approved by MOEE prior to its recommendation that draft approval be granted for plans of subdivision and condominium, and prior to approval of most official plan amendments.

As part of MOEE's recommendation that draft approval be granted, MOEE will request a condition of final approval which specifies that the MOEE receive a copy of a fully-executed subdivision/condominium agreement or other suitable development agreement between the municipality and the developer. The agreement will require that the recommendations of the impact assessment report as approved by MOEE (or its agents) be implemented.

For industrial or commercial development applications involving individual on-site systems, the approval Authority should ensure that a municipal by-law is enacted for the subject lands restricting the industrial/commercial uses to "dry industrial/commercial uses".

Definitions (7.0)

Combined Impact
This refers to the blended impact of all the individual on-site systems on the development site. The impact of the system’s effluent discharge on groundwater is not assessed on a plume by plume basis.
Either the Director under Part VIII of the Environmental Protection Act or the Regional Director of the MOEE.
Individual On-site Sewage System
An on-site Class 4 or Class 6 sewage system regulated by Ontario Regulation 358 under the Environmental Protection Act.
Supply Aquifers
For the purposes of this guideline, a supply aquifer is defined as groundwater which is or which may be used to provide domestic water supply(ies). Designation of groundwater for other than domestic consumption is at the Director’s discretion (see Section 5.3).
Dry Industrial/Commercial Uses
Those uses in which only the disposal of the domestic waste of employees is permitted and treated. No industrial liquid wastes, wash or cooling water or process wastes are permitted.
Hydrogeologically Isolated
Those areas characterised by strong upward hydraulic gradients; massive, unfractured clay deposits at or near ground surface; or other thick impervious layers of materials over water-bearing formations.

Reference documents (8.0)

Other documents that should be used in conjunction with this Guideline include:

  • The Provincial Policy Statement, Ministry of Municipal Affairs & Housing;
  • "Technical Guideline For Water Supply Assessment For Private Wells: Water Supply Assessment", MOEE.
  • "Manual of Policy, Procedures and Guidelines for On-site Sewage Systems", MOEE.
  • "Class Environmental Assessment for Municipal Sewage and Water Projects", Municipal Engineers Association.
  • "Class Environmental Assessment Document: Expansion or Upgrading of an Existing Sewage or Water System", Ecologistics Limited and MOEE.


Notice 3/87

To: Directors, Part VII, Environmental Protection Act
Re: Protection of ground water quality

Ministry of the Environment Policy No. 15-085 "Incorporation of the Reasonable Use Concept Into MOE Ground Water Management Activities" came into effect April 25, 1986. A copy of the Policy and the referenced document entitled "The Incorporation of the Reasonable Use Concept Into the Ground Water Management Activities of the Ministry of the Environment" - September 1986 are appended for your information.

This policy and its appended document establish the basis for determining the reasonable use of ground water on property adjacent to sources of contaminants, and addresses the levels of contaminate discharge considered acceptable by the Ministry. The document establishes procedures for the determination of what constitutes reasonable use of ground water.

It will be noted that the document and the policy are considered to apply to large subsurface sewage systems (i.e., systems regulated by O. Reg. 374/81, under Part VII Environmental Protection Act).

The fundamental principles contained in Policy 15-08 and its attached document are already embraced in the "Manual of Policy Procedures and Guidelines for Private Sewage Disposal Systems"(Chapter 8 and Chapter 14), and only formalize those concerns for the purpose of implementing the Ministry’s overall water quality management program as defined in the MOE publication "Water Management-Goals, Policies, Objectives and Implementation Procedures of the Ministry of the Environment".

As you are all aware there is no definition of a large subsurface sewage disposal system contained in either the Environmental Protection Act or O. Reg. 374/81. The Regulation does however contain a definition for a Class A system, and Chapter 14 of the "Manual of Policy, Procedures and Guidelines for Private Sewage Systems" does provide guidance respecting large systems.

For the purposes of implementation of Ministry Policy 15-08, we have defined Large Subsurface Sewage Disposal System as a subsurface system that:

  1. has an average daily flow greater than 4500 L/d;
  2. serves more than five private residences/dwelling units, with a communal subsurface sewage system; or
  3. serves more than five private residences/dwelling units with adjacent individual sub-surface sewage systems and which will be located in a municipality or an area of a municipality designated by the Part VII Director, and/or the Regional Director of the Ministry of the Environment; or
  4. serves any institution, industrial or commercial establishment;

    but does not include a sub-surface sewage system that:

    1. serves an institutional, industrial or commercial establishment with an average daily flow less than 4500 L/d whose waste water consists solely of sewage of domestic origin, which is human body waste, toilet or other bathroom waste, and liquid or water-borne culinary sink waste.

Clause c) above permits either the Part VII Director or the MOE Regional Director to designate a municipality or an area of a municipality as subject to Policy 15-08. In such designated areas, any subdivision of more than five private residences/dwelling units with adjacent individual sub-surface sewage systems will be subject to Policy 15-08. Prior to the designation of a municipality or an area of a municipality under Clause c) the respective Directors or their staff should consult with each other in order to establish/clarify the reasons for the designation and to ensure there is no misunderstanding or confusion.

The purpose of this Notice is to provide all Part VII Directors with guidelines respecting the implementation of Ministry Policy15-08. The suggested implementation procedures are as follows:

  1. In the "Manual of Policies, Procedures and Guidelines for Private Sewage Disposal Systems" it is recommended that applicants proposing large systems undertake to have a preconsultation meeting with the Part VII Director in order to establish fundamental design criteria etc. for the proposed works. When such meetings are held, Policy 15-08 and its appended document should be brought to the attention of the applicant and the applicant should be requested to address the concerns of the policy and document. As a first step the applicant should confirm the applicability of the policy with the appropriate MOE Regional Office. The decision of the MOE Regional Office and any subsequent assessment of ground water contamination etc. should be included in the applicant’s submission to the Part VII Director.
  2. Where the MOE Regional Office has determined that Policy 15-08applies to a specific application, the report and assessment proposed by the applicant’s consultant should be submitted to the MOE Regional Office by the Part VII Director for review and comment back to the Part VII Director.
  3. When a Part VII Director receives an application for which no pre-consultation meeting has been held or the proponent has not been advised of Policy 15-08, it is recommended that the application be forwarded to the MOE Regional Director for a determination as to the applicability of the policy. Where the MOE Regional Office determines that the policy is applicable, the Part VII Director should so advise the applicant in order that the required assessment may be prepared. This assessment should be forwarded to the MOE Regional Office by the Part VII Director for review, comment and acceptance/rejection.
  4. When an MOE Regional Office cannot support the assessment of the applicant’s consultant regarding the impact of the proposed undertaking the applicant should be so advised by the Part VII Director. Should the applicant choose to appeal the decision MOE Regional staff will act as expert witnesses on behalf of the Part VII Director at the Environmental Appeal Board Hearing.

Should you have any questions respecting the preceding or the attached we would request that you contact either the Technical Support Manager of the MOE Regional Office or, Mr. Brian J. Cooper, On-Site Sewage Systems, (416) 323-4503.

The original Notice 3/87 document was signed by:
W.R. Balfour Director Environmental Approvals and Land Use Planning Branch
C.E. McIntyre Executive Director Approvals and Engineering

1 Please note that this hydrogeologic study is not the assessment described in the MOEE "Manual of Policy, Procedures and Guidelines for On-Site Sewage Systems."That assessment determines the hydraulic capability of the soil to disperse effluent from a leaching bed on a continuous basis, and does not take into account the potential for contamination of the groundwater. However, it is recommended that this impact prediction not be conducted in isolation from the requirements of this and other related guidelines.

2 Suitability of the lot for a sewage disposal system is also dependent on approval from the Director under Part VIII of the Environmental Protection Act. See the MOEE "Manual of Policy, Procedures and Guidelines for On-site Sewage Systems."

3 This is based on expected actual flows of 1000 L/day and a minimum value of 40 mg/L nitrate-nitrogen in the discharge from a Class 4 or Class 6 system (see O. Reg. 358) treating domestic/household sewage.

4 This was derived by simplifying the equation (40 mg/L × Flow) ÷ (Flow + Infiltration) = 10 mg/L - Background

5 MOE Policy No. 15-08 is now known as MOEE Guideline No. B-7.