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Adjusting the pH in Drinking Water

The water Denver Water delivers to customers is lead-free. And for decades, Denver Water has protected its customers from the effects of customer-owned lead-containing water service lines and household plumbing in a variety of ways, including adjusting the pH of the water it delivers to customers.

In March 2020, Denver Water will be increasing the pH level of the water it delivers to customers as part of its Lead Reduction Program. The program was approved by the Environmental Protection Agency and the Colorado Department of Public Health and Environment in December 2019.

The pH level of drinking water reflects how acidic or basic it is. PH is measured on a scale of 0 to 14, with 7 considered neutral, meaning there’s a balance between the water’s acidity and basicity.

For years, the water Denver Water delivers to customers has had a pH that ranged between 7.5 to 8.5, with a target of 7.8. During the first week of March, Denver Water will be increasing the pH range to be between 8.5 and 9.2, with a target of 8.8.

This change is being done to reduce the corrosivity of the water, which will help protect customers who have plumbing in their homes that contains lead, such as customer-owned water service lines that connect their home to the Denver Water’s main delivery pipe in the street, solder that connects sections of pipe in their home and faucet parts.

If you live outside the city of Denver and are unsure if you receive water from Denver Water, please visit our Service Area webpage.

FAQs

What is pH and why is Denver Water adjusting it?

The pH level of drinking water reflects how acidic it is. PH is measured on a scale of 0 to 14, with 7 considered neutral, meaning there’s a balance between the water’s acidity and basicity.

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pH scale, which runs from 0 to 14. Right now Denver Water has a target of 7.8. The goal target is 8.8.

In 1994, Denver Water and state health officials determined that raising the pH of tap water could reduce its corrosive power, thereby reducing the likelihood of lead getting into water as it passes through customer-owned water service lines, household plumbing and faucets that contain lead.

For years, the water Denver Water delivers to customers has had a pH that ranges between 7.5 to 8.5, with a target of 7.8. During the first week of March 2020, Denver Water will be increasing the pH range to be between 8.5 and 9.2, with a target of 8.8.

The pH level of drinking water varies based on a variety of factors, including the source of the water and the treatment steps that are needed. State health officials say that among water systems in Colorado that serve more than 50,000 people, the City of Westminster, under the guidance of the Colorado Department of Public Health and Environment, has maintained a pH of about 8.5 to 8.6 in their drinking water for the last six years.

CDPHE officials also say there are no health concerns about drinking water with pH levels at 8.8.

Other cities that adjust the pH of their water to levels above 8 on the pH scale include:

  • The Massachusetts Water Resources Authority, which serves 3.1 million people in 61 communities including Boston, adjusts its water to a pH of about 9.0 to 9.5. The authority says the adjustment “helps to reduce the potential that water will leach metal that might be in your household plumbing.”
  • The city of Ottawa, Canada, which serves about 900,000 residential, commercial and industrial customers, adjusts its water to a pH that is between 9.2 and 9.4 “to minimize the amount of lead and other metals that can dissolve into tap water.”

Some bottled water has a higher pH and is marketed as alkaline water, which proponents say has health benefits. But the Mayo Clinic says more research is needed to verify these claims.

How will Denver Water raise the pH level?

Denver Water has been and will continue using sodium hydroxide, also known as lye or caustic soda, to raise the pH of the water. This inorganic compound also is used to make soap and paper.

Why is Denver Water doing this?

Increasing the pH is part of Denver Water’s Lead Reduction Program, approved by health officials at the Colorado Department of Public Health and Environment and the Environmental Protection Agency in December 2019. The program also includes replacing an estimated 64,000 to 84,000 customer-owned lead service lines with copper lines and providing customers with filters certified to remove lead from drinking water.

When will this happen?

Denver Water will raise the pH of the drinking water to the new target range in early March 2020.

In the past, the water Denver Water delivers to customers had a pH that ranged between 7.5 to 8.5, with a target of 7.8. The new pH range is between 8.5 and 9.2, with a target of 8.8.

How does raising the pH of the water protect me from lead getting into drinking water?

The water Denver Water delivers to customers is lead-free, but lead can get into the water as it passes through customer-owned water service lines that connect homes to Denver Water’s main delivery pipe in the street, the solder that connects sections of pipe in their home and faucet parts that contain lead.

Learn more about the sources of lead in drinking water.

Raising the pH of drinking water will make the water less corrosive. This change also strengthens an existing protective coating on the interior of the pipe. The coating reduces the likelihood of lead getting into the water as it passes through customer-owned water service lines, household plumbing and faucets that contain lead.

How can I find out if I have a water service line or household plumbing that contains lead?

Denver Water has a lot of information on the sources of lead in drinking water as well as its Lead Reduction Program that will protect our customers and future generations from the risk of lead in drinking water.

Will I notice a change in the water?

State health officials have no concerns about the health impacts of raising the pH of drinking water. Raising the pH of the drinking water won’t affect its taste or odor. You may notice that the water feels more “slippery.”

What about my pets, especially my fish?

You should consult with your veterinarian or local fish or aquarium store for guidance. Different kinds of fish prefer different ranges of pH. For instance, freshwater fish, in general, prefer a lower pH than saltwater fish.

Fish experts say testing the water in the fish tank is a good regular practice, and there are steps you can take to lower the pH of the water if needed, such as introducing a piece of driftwood or adding a chemical to reduce the pH.

I have equipment and machines that may be affected, what should I do?

This change in pH may affect the operations and/or maintenance procedures of your business or equipment. You should consult the manufacturer or operator of the equipment.