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Orthophosphate in treated water

We care about the health and wellbeing of our customers, and we take our commitment to providing safe, reliable drinking water very seriously. While there is no measurable amount of lead in drinking water when it leaves our treatment plants, EPCOR adds orthophosphate to the water treatment process. This is part of our Enhanced Lead Mitigation Strategy​ to help protect Edmontonians from the harmful effects of lead that can get into water from household plumbing fixtures and lead water service lines. It also helps ensure drinking water meets Health Canada’s guidelines for lead in drinking water. ​​​​​

How orthophosphate is used for water treatment​

Orthophosphate is a safe, tasteless and odourless substance that is naturally present as phosphate in foods like bread, cheese, fruits and nuts. In fact, you’d have to drink 104 glasses of water to match the amount of phosphorus found in one banana.​ The phosphoric acid that is added to the treated drinking water to produce orthophosphate is certified to the NSF/ANSI/CAN 60 standard, Drinking Water Treatment Chemicals – Health Effects.​​​

Orthophosphate forms a protective coating inside water lines and household plumbing. It is a proven water treatment method and industry standard ​​to prevent corrosion and reduce the amount of lead in drinking water. Orthophosphate is used by many cities worldwide and throughout North America including Toronto, Hamilton, Winnipeg, Halifax, New York City and Washington, D.C.​ ​​

Enhancing our Lead Mitigation Strategy

EPCOR began managing lead levels in 2008 by removing household lead water service lines with high lead levels. We supplement this protection by adding orthophosphate to the water treatment process ​to mitigate other sources of lead, like lead solder in household plumbing or lead fixtures in taps. 

Edmonton City Council and City Administration approved the orthophosphate addition in March 2019, and EPCOR added it starting in March 2023.

Ortho​phosphate addition for commercial customers 

The addition of orthophosphate to 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.

We recommend businesses in the manufacturing, food processing, petrochemical production as well as commercial heating sectors review their process requirements to determine if their business may be impacted by the addition of orthophosphate.

EPCOR adds orthophosphate at approximately 3.1 mg/L (or 1.0 mg/L as P). EPCOR will monitor and, over time, optimize the orthophosphate dosing and concentration. 

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

Production and water treatment
Orthophosphate may affect reverse osmosis systems. EPCOR recommends contacting your process equipment consultants to see if you will need to make any required adjustments.
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. 
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.​
Other impacts
Other processes within your business may be impacted by the addition of orthophosphate. We recommend talking to a water process consultant or industry association to determine if there are any other impacts to your business or water processes.​

Orthophosphate in water

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Frequently asked questions for commercial customers​​
What areas of businesses might be impacted by the orthophosphate addition?
Areas of your business that may be impacted include: production and water treatment, cooling towers, boilers and other areas. Please see the information for commercial customers section above for more information or contact a process consultant for more details.​
Who should we contact if we have questions about how orthophosphate may impact our water processes?
We recommend contacting a process consultant, equipment consultant or your industry association before orthophosphate is added.
How much orthophosphate will be added to the water?
We will start by adding 1.0 mg/L as P (phosphorous) to our water treatment process in March 2023. Concentrations may change slightly throughout the first year as we adjust for optimization. After levels are optimized, levels should remain stable, with some slight seasonal adjustments as needed.​


Frequently asked questions for residents​

Why did EPCOR 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 of 5 ug/L.
How do people know if they have a lead service line?
If your home was built before 1960, there is a good chance you have lead water service lines for either your public, private or both portions of the lines. EPCOR also sends yearly notifications to Edmonton customers who had public water lines made of lead. While we don’t have records for private water service lines, if the public service line was made from lead, there’s a good chance the private portion of your line is, too. If you aren’t sure what material your water service line is made of, we have provided detailed instructions on how to test for lead pipes​. ​​
How much orthophosphate is added during the water treatment process?
Phosphates are found naturally in foods such as bread, cheese, fruit and nuts. The amount of orthophosphate added during the water treatment process is approximately 3.1 mg/L. In fact, you would have to drink 104 glasses of water to match the amount of phosphorous found 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.​
How does orthophosphate impact backyard water features and aquariums?
The impact on backyard water features and aquariums is minimal. Adding orthophosphate may slightly increase algae growth, meaning water and aquarium gravel and glass may need to be cleaned more frequently. Adding live plants to water features and aquariums may also help with nutrient uptake in aquariums.​
Will orthophosphate impact the environment?

​We are taking a number of steps to ensure we’re protecting the environment. Orthophosphate is effectively removed at our wastewater treatment plants during the treatment process. We’ve also consulted with our regional customers as well to ensure they are prepared to remove orthophosphate during their wastewater treatment processes as well.

We will continue to monitor our progress in removing orthophosphate at our wastewater treatment plants. ​

Will orthophosphate be removed from the water treatment process at some point?
No, once a lead inhibitor like orthophosphate is added to the water treatment process, it must be used continuously to ensure that lead pipes and fixtures do not release lead.​
Can orthophosphate be removed from drinking water?
Using a reverse osmosis system is an option for residents who wish to remove orthophosphate from drinking water.​​​​