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Adding orthophosphate for corrosion control and lead prevention

We care about the health and wellbeing of our customers, and we take our commitment to providing safe, reliable drinking water very seriously. We are protecting our customers from water pipe corrosion and lead in drinking water by adding anti corrosion additives for water including orthophosphate for corrosion control to our water treatment process.

What is orthophosphate used for in water treatment? 

Orthophosphate is a safe, tasteless, odorless substance, naturally present in foods as phosphate that forms a protective coating inside our city’s water infrastructure and inside household plumbing systems. Orthophosphate is a corrosion inhibitor for water service lines, and a proven water treatment method to prevent corrosion and reduce the amount of lead in drinking water

As part of EPCOR’s enhanced Lead Mitigation Program, EPCOR will be adding orthophosphate to our water treatment process in December 2022. Phosphate is a safe additive found naturally in foods such as bread, cheese, fruit and nuts. In fact, you’d have to drink 104 glasses of water with orthophosphate added to match the same amount of phosphorus found in one banana.

 EPCOR has been managing lead levels since 2008 by removing household lead water service that showed high levels of lead; now we are supplementing this with orthophosphate due to other sources of lead that homeowners may not be aware of, like lead solder in the household plumbing or lead fixtures in taps. We expect that the addition of orthophosphate will aid in the prevention of water line corrosion, lower lead levels, and achieve compliance with Health Canada’s lead concentration recommendations.

​The addition of Orthophosphate in drinking water as a lead inhibitor was approved by City Council and City Administration in March 2019, and is the industry standard for reducing lead in water systems used by many municipalities throughout North America including Toronto, Hamilton, Winnipeg, Halifax, New York City and Washington D.C.​

Frequently asked questions about orthophosphate

Why do we need to add a lead inhibitor if only a few homes in Edmonton have lead pipes and service lines​​? 

Lead pipes and service lines are not the only source of lead; our sampling research has shown that lead present in in-home plumbing, old solder and brass fixtures also have the potential to exceed Health Canada’s proposed guideline.

Are there any health effects related to orthophosphate?

Adding a lead inhibitor (orthophosphate) has no negative effects on health. It is commonly used by water utilities across North America and the United Kingdom to prevent lead from entering into drinking water. Phosphate is naturally present in food and is a common additive to beverages. In fact, you would have to drink 104 glasses of tap water to match the phosphorus in one banana.

Is there a difference between orthophosphate and phosphate?

Orthophosphate is a member of the phosphate family. Orthophosphates are small molecules, formed from the smallest and most basic form of phosphorus and are added to processed foods and naturally present in many foods.

Do I need to do anything after orthophosphate is added?

No, residential customers can continue to use the water as they normally would. There is no action necessary once orthophosphate is added. The water will remain safe to drink. Commercial customers that use Edmonton’s water for manufacturing or petrochemical production may need to make adjustments to their water processes.


Ortho​phosphate addition for commercial customers 

The addition of Orthophosphate concentration in the water supply may require businesses that rely on Edmonton’s water for manufacturing, food processing, petrochemical production as well as commercial heating and cooling to make adjustments to their own water processes.

Orthophosphate will be added to Edmonton’s water at the water treatment plants beginning in December 2022. During implementation, the concentration of orthophosphate will begin at 0.9 mg/L. EPCOR will monitor and, over time, optimize the orthophosphate dosing and concentration. We expect the implementation process to take approximately one year where orthophosphate concentrations may fluctuate. We recommend businesses in the manufacturing, food processing, petrochemical production as well as commercial heating sectors review your ​process requirements to determine if your business may be impacted by the addition of orthophosphate. 

Areas where your business may be impacted could include:​​​​

Production and water treatment
Orthophosphate may affect reverse osmosis systems. EPCOR recommends that you contact your process equipment consultants to complete an assessment in advance of December 2022 to determine if you will need to make any required adjustments prior to orthophosphate implementation.

Cooling towers
Orthophosphate in the water may change the type and amount of precipitate that deposits on commercial heat exchangers. Companies may need to adjust their chemical treatment to account for the change in phosphate levels. It is recommended that companies contact their heating and cooling supplier, water treatment chemical provider or water process consultant to discuss the need for adjustment to your heating and cooling system.
The impact of orthophosphate on boilers is expected to be minimal. Many customers already add phosphate to precipitate calcium or as a tracer in their boiler system. For this reason, companies already adding phosphate may benefit from the addition of orthophosphate. Companies that already add phosphate may need to adjust their dosage levels accordingly or apply for an overstrength permit for discharge of their wastewater.

There may be other processes within your business that we have not identified that may be impacted by the addition of orthophosphate. We recommend that you discuss these changes with a water process consultant or industry association to determine if there is an impact to your water process.​​

Looking for more information: 

You can also reach out to our Orthophosphate Program Representative if you have any questions regarding the orthophosphate treatment process:​