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Document ID ca-gcdwqgtd-2014-08-27-2 Title Guidelines for Canadian Drinking Water Quality: Guideline Technical Document - Nitrate and Nitrite URL https://www.canada.ca/en/health-canada/services/publications/healthy-living/guidelines-canadian-drinking-water-quality-guideline-technical-document-nitrate-nitrite/page-3-guidelines-canadian-drinking-water-quality-guideline-technical-document-nitrate-nitrite.html Jurisdiction /ca Subdomain(s) Drinking water, Source water protection, Regulatory compliance Language en Status completed Analyzed at 2026-03-18 15:23:18.928857+00:00 Relevance Technical document supporting Canadian drinking water standards for nitrate.

35 Qualitative 10 Quantitative 34 Definitions

Q Qualitative Requirements (35)

Req ID	Category	Intent	Legal Status	Name	Subdomain(s)	Context	Conditions	Confidence
#Q001	monitoring	operational	recommended	Individual Nitrate/Nitrite Sample Preservation and Holding Time	drinking water	Samples to be analysed for nitrate or nitrite individually should be cooled to 4°C and analysed within 48 hours.	Analysis using EPA Method 300.0 or 300.1 for nitrate or nitrite individually	high
#Q002	monitoring	operational	recommended	Combined Nitrate and Nitrite Sample Preservation and Holding Time	drinking water	Samples for combined nitrate and nitrite analysis should be acidified using sulphuric acid to a pH less than 2 and analysed within 28 days (U.S. EPA, 1993).	Analysis using EPA Method 300.0 or 300.1 for combined nitrate and nitrite	high
#Q003	monitoring	reporting	mandatory	Nitrite Correction for EPA Method 353.2	drinking water	To use this method, a correction must be made for any nitrite present by analysing without the reduction step.	When using EPA Method 353.2 revision 2.1 (automated cadmium reduction with colorimetry)	high
#Q004	monitoring	operational	mandatory	EPA Method 353.2 Sample Preservation	drinking water	Samples must be preserved using sulphuric acid to a pH less than 2 and cooled to 4°C at the time of collection (U.S. EPA, 1993).	When using EPA Method 353.2 revision 2.1	high
#Q005	operational	treatment	recommended	Minimization of Nitrate Levels	drinking water	Treatment plants should strive to minimize nitrate levels in the treated water.		high
#Q006	operational	operational	mandatory	Ion Exchange Brine Disposal	drinking water	Regeneration results in a brine waste stream that contains high nitrate concentrations and must be disposed of appropriately.	When using conventional ion exchange process for nitrate removal	high
#Q007	treatment	operational	mandatory	Ion Exchange Post-Treatment Corrosion Control	drinking water	In some cases, post-treatment corrosion control measures must be taken to ensure that corrosion problems do not occur in the distribution system following treatment using ion exchange (Schock and Lytle, 2011).	When mineral imbalances increase the corrosive nature of treated water following ion exchange	high
#Q008	design	treatment	mandatory	Reverse Osmosis System Viability Requirements	drinking water	In general, when utilities are considering reverse osmosis systems primarily for nitrate removal, the systems must demonstrate high nitrate rejection, high water flux and a high recovery rate for the systems to be economically viable	When considering reverse osmosis primarily for nitrate removal	high
#Q009	operational	operational	mandatory	Reverse Osmosis Concentrate Disposal	drinking water	Reverse osmosis rejects a significant portion of the influent water as contaminant-rich brine (Taylor and Wiesner, 1999), and the concentrate discharge must be disposed of appropriately.	When using reverse osmosis	high
#Q010	treatment	operational	mandatory	Reverse Osmosis Post-Treatment Corrosion Control	drinking water	The removal of contaminants can cause mineral imbalances that could increase the corrosive nature of the treated water (Schock and Lytle, 2010). In most cases, post-treatment corrosion control measures need to be taken.	When using reverse osmosis	high
#Q011	operational	treatment	mandatory	Biological Denitrification Optimization	drinking water	As nitrite is an intermediate compound in the reduction of nitrate to nitrogen gas, utilities need to ensure that their systems are optimized so that the biological process is complete and nitrite is not present in the treated water.	When using biological denitrification processes	high
#Q012	monitoring	health	recommended	Distribution System Nitrification Monitoring	drinking water	Utilities that are chloraminating should monitor for nitrite and nitrate in the distribution system in addition to ammonia, total chlorine residual, HPC and other nitrification indicators.	For utilities that are chloraminating	high
#Q013	administrative	operational	recommended	Nitrification Monitoring Program Alert/Action Levels	drinking water	The program should identify system-specific alert and action levels, which can be used to determine the appropriate level of action to address nitrification.	When establishing a nitrification monitoring program	high
#Q014	monitoring	operational	recommended	Triggered Monitoring for Free Ammonia	drinking water	Changes in the trend of priority nitrification parameters (such as total chlorine residual, nitrite and nitrate) in the distribution system should trigger more frequent monitoring of other parameters such as free ammonia.	When trends in priority nitrification parameters change	high
#Q015	operational	health	mandatory	Chlorite Addition Control Strategy Limits	drinking water	Utilities wishing to use chlorite addition as a control strategy should ensure that Health Canada's guidelines for chlorite and chlorate are not exceeded (Health Canada, 2008).	When using chlorite addition to control nitrification	high
#Q016	operational	operational	recommended	Nitrification Prevention Strategy Selection	drinking water	For these reasons, comprehensive strategies aimed at the prevention of nitrification episodes are recommended over strategies aimed at controlling nitrification as they occur.		medium
#Q017	monitoring	health	recommended	Residential Source Water Testing Prior to Device Installation	drinking water	Before a treatment device is installed, the water should be tested to determine general water chemistry and verify the presence and concentrations of nitrate and nitrite in the source water.	Before installing a residential treatment device	high
#Q018	monitoring	health	recommended	Residential Treatment Device Efficacy Testing	drinking water	Periodic testing by an accredited laboratory should be conducted on both the water entering the treatment device and the finished water to verify that the treatment device is effective.	For residential treatment devices	high
#Q019	operational	operational	recommended	Verification of Residential Component Longevity	drinking water	Consumers should verify the expected longevity of the components in their treatment device as per the manufacturer's recommendations.	For residential treatment devices	high
#Q020	design	health	recommended	Residential Treatment Device Certification Requirement	drinking water	Health Canada does not recommend specific brands of drinking water treatment devices, but it strongly recommends that consumers use devices that have been certified by an accredited certification body as meeting the appropriate NSF International (NSF)/American National Standards Institute (ANSI) drinking water treatment unit standards.	When selecting residential treatment devices	high
#Q021	design	health	recommended	Point-of-Use Installation for Distillation Systems	drinking water	Distillation systems should only be installed at the point of use as the water they have treated may be corrosive to internal plumbing components.	When installing residential distillation systems	high
#Q022	design	health	recommended	Point-of-Use Installation for Reverse Osmosis Systems	drinking water	Reverse osmosis systems should only be installed at the point of use as the water they have treated may be corrosive to internal plumbing components.	When installing residential reverse osmosis systems	high
#Q023	design	health	recommended	Certification of Ion Exchange Systems Construction Materials	drinking water	Health Canada strongly recommends that homeowners ensure that these systems are constructed using materials certified to NSF/ANSI Standard 61 (NSF/ANSI, 2009d).	For residential ion exchange systems	high
#Q024	treatment	health	recommended	Alternative Treatment for Source Water with Sulphate	drinking water	If a nitrate-selective resin is not available, homeowners whose source water contains sulphate should consider the use of an alternative treatment.	When nitrate-selective resin is not available and source water contains sulphate	high
#Q025	monitoring	operational	guidance	Residential Ion Exchange Routine Monitoring	drinking water	It is important to routinely monitor the nitrate concentration in the water treated by ion exchange to ensure that the system is effectively removing nitrate and that chromatographic peaking is not occurring.	When using residential ion exchange treatment	high
#Q026	operational	treatment	mandatory	Ion Exchange Resin Regeneration	drinking water	Once the resin has reached its capacity (i.e., when the nitrate ion begins to appear in significant concentration in the column effluent) the resin must be regenerated using a sodium chloride (salt) solution to reverse the process.	When the ion exchange resin has reached capacity	high
#Q027	design	operational	mandatory	Ion Exchange Operational Considerations	drinking water	Utilities need to give careful consideration to the level of nitrate breakthrough, the percentage of raw water that bypasses ion exchange treatment and the use of partial regeneration when determining the lowest achievable nitrate concentration using ion exchange treatment.	When determining achievable nitrate concentrations for ion exchange systems	high
#Q028	operational	operational	mandatory	Electrodialysis Operational Requirements	drinking water	The main considerations for systems using electrodialysis and electrodialysis reversal for nitrate removal are the operational complexity of the system, disposal of the reject water and the need for pH adjustment of the treated water.	When using electrodialysis or electrodialysis reversal	high
#Q029	operational	treatment	guidance	Residential RO Influent Pre-treatment	drinking water	A consumer may need to pre-treat the influent water to reduce fouling and extend the service life of the membrane.	When using residential reverse osmosis systems to extend service life	high
#Q030	monitoring	operational	mandatory	Nitrification Monitoring Program Site-Specific Evaluation	drinking water	A site-specific evaluation is generally necessary to establish a nitrification monitoring program.	When establishing a nitrification monitoring program for chloraminated systems	high
#Q031	operational	health	recommended	Nitrification Strategy Guideline Compliance	drinking water	Any strategy should also ensure that other Guidelines for Canadian Drinking Water Quality are not exceeded.	When implementing preventive or control measures for nitrification	high
#Q032	design	treatment	mandatory	Reverse Osmosis Pretreatment Requirements	drinking water	Reverse osmosis treatment systems typically require prefiltration for particle removal and often include other pretreatment steps, such as the addition of anti-scaling agents, prechlorination/dechlorination and softening.	When designing municipal scale reverse osmosis systems	high
#Q033	design	treatment	mandatory	Biological Denitrification Post-Treatment Requirement	drinking water	In general, biological denitrification treatment systems require post-treatment to remove biomass and biodegradable organic materials that are present in the reactor effluent.	When using biological denitrification for potable water treatment	high
#Q034	design	treatment	recommended	Nanofiltration Membrane Performance Testing	drinking water	Therefore, testing of the nanofiltration membrane selected for nitrate removal will be an important step for utilities considering this treatment process.	For utilities considering nanofiltration for nitrate removal	high
#Q035	design	operational	recommended	Ion Exchange Resin Selection Considerations	drinking water	The ion exchange capacity and the selectivity of the resin are important considerations when selecting a resin.	When selecting strong base anion or nitrate-selective resins	high

P Quantitative Requirements (10)

Req ID	Category	Intent	Legal Status	Name	Subdomain(s)	Limit Type	Limit Value	Context	Conditions	Confidence
#P001	chemical	health	mandatory	Nitrite and nitrate	other	requirement	<= 200 mg/kg	Health Canada has limited the amount of nitrite and nitrate that can be added to meat products	Added to meat products as preservatives	high
#P002	chemical	health	guideline	Nitrite	drinking water	unknown	1.0 mg NO2-N/L	the increase in nitrite due to nitrification may lead to a concentration that exceeds the guideline value of 1.0 mg NO2-N/L	Distribution systems experiencing nitrification	high
#P003	chemical	health	guideline	Nitrite	drinking water	unknown	3 mg NO2¯/L	guideline value of 1.0 mg NO2-N/L (equivalent to 3 mg NO2¯/L)	Distribution systems experiencing nitrification	high
#P004	chemical	operational	guidance	Nitrite	drinking water	OG	0.05 mg NO2-N/L	a nitrite level of 0.05 mg NO2-N/L (equivalent to 0.16 mg NO2¯/L) may be used as a critical threshold indicator in nitrification	Critical threshold indicator in nitrification	medium
#P005	chemical	operational	guidance	Nitrite	drinking water	OG	0.015 mg NO2-N/L	Smith (2006) further suggested that a nitrite concentration of 0.015 mg NO2-N/L (equivalent to 0.048 mg NO2¯/L) should be used as an action level for utilities to address nitrification	Action level to address nitrification in the distribution system	medium
#P006	chemical	treatment	mandatory	Nitrogen	drinking water	requirement	10 mg-N/L	The NSF/ANSI standards for nitrate and nitrite removal currently require testing of a device for the reduction of 30 mg-N/L as nitrogen (27 mg NO3-N/L plus 3 mg NO2-N/L) to 10 mg-N/L of nitrogen	NSF/ANSI device testing requirement	high
#P007	chemical	treatment	mandatory	Nitrite-nitrogen	drinking water	requirement	<= 1 mg/L	in which no more than 1 mg/L can be in the form of nitrite-nitrogen	NSF/ANSI device testing requirement for nitrogen reduction	high
#P008	chemical	health	guideline	Nitrate	drinking water	MAC	10 mg NO3-N/L	Control options for addressing nitrate concentrations above 10 mg NO3-N/L (equivalent to 45 mg NO3¯/L) in source water used for drinking		high
#P009	chemical	health	guideline	Nitrate	drinking water	MAC	45 mg NO3¯/L	Control options for addressing nitrate concentrations above 10 mg NO3-N/L (equivalent to 45 mg NO3¯/L) in source water used for drinking		high
#P010	chemical	reporting	mandatory	Nitrate and Nitrite Practical Quantitation Limit	drinking water	requirement	0.4 mg N/L	The current U.S. EPA practical quantitation limit (PQL), based on the capability of laboratories to measure the concentrations within reasonable limits of precision and accuracy, is 0.4 mg N/L.	Based on the capability of laboratories to measure concentrations within reasonable limits of precision and accuracy	high

D Definitions (34)

Req ID	Name	Context	Confidence
#D001	AOB	ammonia-oxidizing bacteria	high
#D002	NOB	nitrite-oxidizing bacteria	high
#D003	RSN	residual soil nitrogen	high
#D004	EPA	U.S. Environmental Protection Agency	high
#D005	MDLs	method detection limits	high
#D006	PQL	practical quantitation limit	high
#D007	MIEX	magnetic ion exchange	high
#D008	ISEP	continuous ion exchange separation	high
#D009	ULPRO	ultra low pressure reverse osmosis	high
#D010	NDMA	N-nitrosodimethylamine	high
#D011	DMA	dimethylamine	high
#D012	RO	reverse osmosis	high
#D013	NSF	NSF International	high
#D014	ANSI	American National Standards Institute	high
#D015	SCC	Standards Council of Canada	high
#D016	NOS	nitric oxide synthase	high
#D017	NIS	sodium/iodide symporter	high
#D018	Nitrification	a two-step process during which ammonia is oxidized to nitrite, which further is oxidized to nitrate by ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB), respectively	high
#D019	Denitrification	the denitrification process further reduces nitrite to nitrogen gas	high
#D020	Ion exchange	a physicochemical process in which there is an exchange of ions in the raw water with ions within the solid phase of a resin	high
#D021	Nitrate breakthrough	when the nitrate ion begins to appear in significant concentration in the column effluent	high
#D022	Chromatographic peaking	causing the effluent nitrate concentration to be greater than the influent nitrate concentration due to sulphate ions displacing nitrate ions on the resin	high
#D023	Bypass blending	diverting a portion of the influent flow around the treatment vessel and blending the diverted water with the treated effluent water	high
#D024	Partial regeneration	removal of only 50-60% of the exchanged nitrate on the resin	high
#D025	Electrodialysis	a membrane process that uses an electric potential for removing charged species from water	high
#D026	Heterotrophic denitrification	uses organic compounds, such as ethanol or acetic acid, as both the electron donor and carbon source	high
#D027	Autotrophic denitrification	uses an inorganic compound such as hydrogen or sulphur as the electron donor and inorganic carbon such as carbon dioxide as the carbon source	high
#D028	SM	Standard Methods for Water and Wastewater	high
#D029	Biological denitrification	treatment processes are based on the removal of nitrate in source water through the biological reduction of nitrate to nitrogen gas (denitrification) in an anoxic environment	high
#D030	Electrodialysis reversal	based on reversing the polarity of the electrodes several times every hour of operation to alter the direction of ion movement, which greatly helps to reduce membrane scaling	high
#D031	CARIX process	uses a mixed bed with a weakly acidic and a strongly basic exchanger material for the removal of a variety inorganic minerals including calcium, magnesium, sulphate and nitrate	high
#D032	Nitrifiers	nitrifying bacteria	high
#D033	Chemical denitrification	chemical reduction of nitrate to other nitrogen species	high
#D034	Catalytic denitrification	chemical denitrification of nitrate in the presence of catalyst	high