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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 home 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. This is being done as part of the Lead Reduction Program, which was approved by state and federal health officials.

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. Increasing the pH of the water is proven technique used by many water utilities to protect customers from the likelihood of lead or other metals getting into drinking water.

In Colorado, state health officials say that among water systems 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.

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.”
  • The San Francisco Public Utilities Commission, which serves 2.7 million residential, industrial and commercial customers in the city and 27 suburban agencies, adjusts the pH of the water throughout the year in a range from 7.8 to 9.9, with an average of 9.4, as the sources of the city’s water supply change.

Officials with the Colorado Department of Public Health and Environment say there are no health concerns about drinking water with pH levels at 8.8, Denver Water’s target on the pH scale as of March 2020.

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 water pitchers and filters certified to remove lead from drinking water. This is being done at no direct cost to the customer.

When will the increase in pH happen?

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

Since the mid-1990s, Denver Water has adjusted the pH of the water it delivers to customers to reduce the risk of lead and other metals from getting into drinking water. Prior to March 2020, the pH ranged between 7.5 and 8.5, with a target of 7.8. After the change takes place, during the first week of March 2020, the pH range will 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 lead-containing customer-owned water service lines that connect homes to Denver Water’s main delivery pipe in the street (lead service lines are more likely if the home was built prior to 1951), the solder that connects sections of pipe in their home (if installed prior to 1987) and faucet parts (if made prior to 2014).

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 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?

The Lead Reduction Program, including the pH increase, was approved by both the EPA and CDPHE after thorough study of how the change would impact the Denver’s water system and the quality of the water. Raising the pH of the drinking water won’t affect its taste or odor. You may notice that the water feels more “slippery.”

Will my lawn, plants and landscape be OK?

Denver Water has been and continues to work with irrigation and landscape experts locally and nationwide to learn more about any potential impacts from the pH increase.

The feedback we’re hearing so far, from scientists and experts in other cities where the water has a higher pH level, is that in general there should not be any major impacts on plants and landscapes. Specific plants and circumstances may call for best management practices to be used.

During irrigation, such as using sprinklers, pH levels in the water drop when it is exposed to the CO2 (carbon dioxide) in the air. We’re also hearing from soil scientists that the higher pH should be no problem due to the natural buffering capacity of the soil that helps prevent major impacts on plants.

Denver Water is continuing to work with experts and other cities who have plants and parks in this pH range to learn more so we can appropriately communicate any best management practices that may be necessary to help mitigate any anticipated issues.

What about my pets, especially my fish?

You should consult with your veterinarian or local fish or aquarium store for guidance. But experts at Colorado State University indicate there hasn’t been a lot of research on pH levels in water impacting pets.

For fish, different kinds of fish prefer different ranges of pH. For instance, freshwater fish, in general, prefer a lower pH than saltwater fish.

Experts at Colorado State University say it’s a good practice to regularly test the pH of the water in the fish tank and also to test and adjust the water if needed prior to adding it to the tank.

Fish store operators in the Denver area indicate there are steps that can be taken to lower the pH of the water, if needed, such as introducing a piece of driftwood, adding peat moss to a filtration system or adding a chemical to reduce the pH.

I brew beer at home, or have a distillery or brewery in Denver Water’s service area, what should I do?

Raising the pH of the water used in brewing operations can affect the process of crafting beer or spirits. Homebrewers should ask their local homebrew shop for suggestions on appropriate products to reduce pH.

Breweries and distilleries typically have their own procedures for testing and adjusting water used in their operations and should continue to follow those procedures. The Colorado Brewers Guild recommends that Denver brewers acquire an independent water analysis of their brewing water to evaluate the specific impact.

Denver Water’s website has additional information useful to brewers and distillers available. This information will be updated following the change in pH.

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

This change in pH in general will increase the amount of “scaling” on equipment — the white mineral deposits that can be seen after water has dried. The pH increase also will increase the alkalinity of the water. The water Denver Water delivers is typically at or above 40mg/L as CaCO3.

This increase 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.

Regarding dialysis equipment, Denver Water contacted DaVita, which as of December 2019 provided dialysis services to more than 235,000 patients in the U.S. and 10 other countries. DaVita said the pH change for Denver Water’s service area poses no risk to dialysis patients and will not affect in-center or home dialysis treatment operations. More information on water quality in dialysis is available on the DaVita’s website.

Will the higher pH change the hardness of the water or cause more scale to form? Should I get a water softener?

Denver Water’s new, higher pH target of 8.8 will not change the hardness of the water. You may notice a small amount of additional scale develop over time where hot water is in contact with fixtures and appliances, such as hot water heaters, dishwashers and showerheads. Follow the manufacturers’ directions for care and maintenance of these appliances.

Adding a water softener to your home should be approached with caution because softeners add sodium to the environment, which can affect the health of plants, animals and people who live downstream of us. It also can undo protective benefits of the higher pH level has on household plumbing that may contain lead. Learn more about sources of lead.