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Glossary of Source Water Terms

Agricultural Source Material

Agricultural source material is treated or untreated material that is capable of being applied to land as a nutrient. Farmers use manure on their farmland, but residential landowners can also apply manure as lawn fertilizer.

The definition from O. Reg. 267/03 includes the following additional categories:

  • Manure produced by farm animals, including bedding materials
  • Runoff from farm-animal yards and manure storages
  • Wash water that has not been mixed with human body waste (e.g. from the milking center)
  • Organic materials produced by intermediate operations that process the above materials (e.g. mushroom compost)
  • Anaerobic digestion output that does not include sewage bio-solids or human body waste (anaerobic digestion is a process used to decompose organic matter by bacteria in an oxygen-limited environment)
  • Regulated compost (which contains dead farm animals) ASM does not include compost that meets the Compost Guidelines, or a commercial fertilizer.


Animal Yard, Confinement Area

An animal confinement area is defined as an enclosure for livestock or game animals that has all of the following characteristics:

  • An unroofed area (with the exception of small wind or shade shelters that are under 20 m2/200 ft2);
  • A grazing or foraging area that accounts for less than 50 per cent of the animals' dry matter intake; or
  • Fences, pens, corrals or similar structures to confine the animals that are either permanent or temporary allowed access to a barn.



From the Latin for "water carrier", a geological formation (typically porous material, such as sand or gravel, or fractured rock) that stores and is capable of transmitting water in sufficient quantities to serve as a sustainable source of water supply.


Assessment Report

The Assessment Report is a technical document which contains information on threats to drinking water quality and quantity for municipal sources. The Assessment Report identifies vulnerable areas and the land-use activities that may pose a threat. This provides a scientific foundation for the Source Protection process. Assessment reports contain information on water budgets, ground and surface water flow, groundwater recharge areas, Intake Protection Zones, and Wellhead Protection Areas where contaminants may enter a drinking water source. The Assessment Report is a living document which will be amended and updated over time as new studies and reports are completed.



Circumstances specify details about what makes an activity a threat. The circumstances were developed because the risk to drinking water can vary depending on the specific details of the activity. Details may include the type of chemical being used, volume of storage and whether storage is above or below ground. For example, the volume of fuel storage which poses a threat is dependent on whether it is stored above or below grade (above ground or in a basement).


Clean Water Act, 2006

The Clean Water Act, 2006 lays out requirements for Source Protection committees to list activities that are or would be drinking water threats in vulnerable areas. Through regulations and technical rules, the Province has set out which activities, at a minimum, must be considered drinking water threats under specific circumstances. Specifically, Section 1.1 of Ontario Regulation 287/07 (General) lists activities that are prescribed as drinking water threats and the Tables of Drinking Water Threats in the Technical Rules specifies under what circumstances these activities are categorized as significant, moderate or low drinking water threats.


Conservation Authority

Conservation authorities (CAs) are local, community based agencies which work with municipalities to manage a watershed. CAs are directed to ensure the conservation, restoration, and responsible management of Ontario's water, land and natural habitats while considering human, environmental, and economic needs. Source Protection is carried out on a watershed scale; for this reason the CA forms the functional unit of the Source Protection Region.


Decommissioning (Septic System)

For the purpose of this Plan, decommissioning of a septic system refers to disconnecting it from the dwelling, pumping out the tank, and collapsing and backfilling the tank or removing the tank entirely. The disturbed area should be returned to grade.


Dense Non-Aqueous Phase Liquid

In general, a dense non-aqueous phase liquid (DNAPL) is defined as a heavier-than water organic liquid that is only slightly soluble in water. DNAPLs can flow through fractures or fissures in fractured rock and clay to sink vertically to the water table and then eventually settle below the water table.

The primary classes of DNAPLs include:

  • 1,4-Dioxane
  • Tetrachloroethylene (Perchloroethylene [PCE])
  • Trichloroethylene [TCE]
  • Vinyl Chloride [VC]
  • Polycyclic Aromatic Hydrocarbons [PAHs]

Any other DNAPL compound which can degrade into one of the above chemicals is also a significant threat.

DNAPL contaminated sites have proven to be complex to investigate and both challenging and costly to remediate. It may take many decades for natural groundwater dissolution or natural breakdown of the DNAPL to dissipate DNAPL sources. Many of these liquids are suspected or proven to be carcinogenic (cancer-causing). Examples of DNAPLs include, but not limited to, furniture stripper, nail polish, dry cleaning fluids, aerosols, coolants, polychlorinated biphenyls (PCBs), creosote and degreasers.


Environmental Compliance Approval

Environmental Compliance Approvals (ECAs) were formerly known as Certificates of Approval (C of A). C of A's were issued by the Ontario Ministry of the Environment (MOE) allowing the regulated discharge of contaminants into the natural environment under Section 9 of the Environmental Protection Act, 1990. The Open for Business Act, 2010 has since changed this process. As of October 31, 2011, the C of A has been replaced by the ECA and an Environmental Activity and Sector Registry (which does not require an approval). The ECAs are expected to be similar to the C of As, but can be used to address multiple activities at a site.


Intake Protection Zone

Intake Protection Zones (IPZs) are areas (land and water) near and upstream of a drinking water intake where human activities may need to be regulated to protect the quality and quantity of surface water that supplies the intake. Land-farming of Petroleum Refining Waste Land-farming is a treatment process that is performed in the upper soil zone or in biotreatment cells. Contaminated soils, sediments, or petroleum-based sludges are incorporated into the soil and periodically turned over (tilled) to aerate the mixture.


Non-Agricultural Source Material

Non-agricultural source material (NASM) means any of the following materials (other than compost that meets the Compost Guidelines or a commercial fertilizer) if the materials are intended to be applied to land as nutrients:

  • pulp and paper bio-solids
  • sewage bio-solids
  • anaerobic digestion output, if less than 50 %, by volume, of the total amount of anaerobic digestion materials that were treated in the mixed anaerobic digestion facility were on-farm anaerobic digestion materials
  • any other material that is not from an agricultural source and that is capable of being applied to land as a nutrient


Organic Solvents

Organic solvents are compounds which are able to dissolve solids, gases and liquids. This includes:

  • Carbon tetrachloride
  • Chloroform
  • Methylene chloride
  • Pentachlorophenol

Some organic solvents are flammable and pose a risk to human health.



A pathogen is a disease-causing organism such as virus, bacterium, prion, or fungus.



The pesticides which pose a significant threat to drinking water are:

  • Atrazine
  • Dicamba
  • Dichlorophenoxy Acetic Acid (D-2,4)
  • Dichloropropene-1,3, MCPB (4-(4-chloro-2-methylphenoxy)butanoic acid )
  • Glyphosate
  • MCPA (2-methyl-4-chlorophenoxyacetic acid)
  • MCPB (4-(4-chloro-2-methylphenoxy) butanoic acid )
  • Mecoprop
  • Metalaxyl
  • Metolachlor
  • s-Metolachlor
  • Pendimethalin


Polychlorinated Biphenyl

Polychlorinated biphenyls (PCB) are man-made substances which were widely used in transformers and capacitors. Due to the toxicity of PCBs, they are no longer used Ontario. PCBs which have not been destroyed are often stored at identified sites. The storage of these chemicals could be a significant threat to drinking water in certain areas.


Prescribed Instrument

A Prescribed Instrument is an instrument defined in Ontario Regulation 287/07 for which a decision to issue, create or amend must conform with significant threat policies set out in the Source Protection Plan.


Public Body

A public body is a municipality, local board or conservation authority, a ministry, board, commission, agency or official of the Government of Ontario, or a body prescribed by the regulations made under the Clean Water Act, 2006.


Risk Management Plan

A Risk Management Plan is a site-specific plan established under Section 58 of the Clean Water Act, 2006 to address significant drinking water threat activities, where the threat cannot be addressed through different means, such as a Prescribed Instrument. This tool cannot be used for waste disposal and sewage-related activities that require an Environmental Compliance Approval under the Environmental Protection Act, 1990 or the Ontario Water Resources Act, 1990, or a permit under the Ontario Building Code.


Secondary Containment (fuel storage)

Secondary containment, provides a barrier between the tank and the environment. The barrier holds any leaks between the tank and the barrier so that the leak is detected. The barrier is shaped so that a leak will be directed towards the interstitial monitor.

Barriers include:

  • Double-walled or jacketed tanks, in which an outer wall partially or completely surrounds the primary tank;
  • Internally fitted liners (bladders); and
  • Leak-proof excavation liners that partially or completely surround the tank. Clay and other earthen materials cannot be used as barriers.


Significant Drinking Water Threat

A drinking water threat that as identified in the Source Protection Plan and table of drinking water threats which poses or has the potential to pose a significant risk to drinking water.


Source Protection Area

A Source Protection Area is those lands and waters that have been defined under Ontario Regulation 284/07 as the 'study area' for an Assessment Report and a Source Protection Plan under the Clean Water Act, 2006.


Source Protection Authority

A Source Protection Authority is a conservation authority or other person or body that is required to exercise powers and duties under the Clean Water Act, 2006.


Source Protection Committee

A Source Protection Committee is a group of individuals who have been appointed under the Clean Water Act, 2006 by a Source Protection Authority to coordinate Source Protection activities for a Source Protection Area or Region.


Source Protection Plan

A Source Protection Plan is a document that is prepared by a Source Protection Committee under Section 22 of the Clean Water Act, 2006 to direct Source Protection activities in a Source Protection Area. Each Plan is approved by the Ontario Ministry of the Environment.


Source Protection Region

A Source Protection Region is two or more Source Protection areas that have been grouped together under Ontario Regulation 284/07.


Source Water

Source water is untreated water that is found in groundwater aquifers and surface water lakes and rivers that is used to supply a drinking water system.



Stormwater refers to any water runoff which makes its way into water bodies via the storm sewer system. For the purpose of this Plan the threat to drinking water is limited to stormwater discharge from management facilities. Stormwater management facilities are designed for the treatment, retention, infiltration and/or control of storm water. This definition also applies to the system of managing stormwater, including stormwater pipes that discharge directly into streams or water bodies.


Vulnerable Area

A vulnerable area is: (a) A significant groundwater recharge area, (b) a highly vulnerable aquifer, (c) an Intake Protection Zone, or (d) a Wellhead Protection Area.


Waste Disposal Sites

Waste disposal sites include:

  • Application of untreated septage to land (hauled sewage)
  • Storage, treatment and discharge of tailings from mines
  • Polychlorinated biphenyl (PCB) storage
  • Land-farming of petroleum refining waste (biodegradation of petroleum waste)
  • Liquid industrial waste injection into a well
  • Landfilling (hazardous, municipal, industrial, commercial waste)
  • Storage of hazardous waste at a disposal site
  • Storage of wastes described in clauses (p), (q), (r), (s), (t) or (u) of the definition of hazardous waste


Wellhead Protection Area

A Wellhead Protection Area (WHPA) is the area of land surrounding a well, where human activities may need to be regulated to protect the quality and quantity of ground water that supplies that well.