Town News

Town of Frisco Water Department to Install Corrosion Control System at Town Water Sources

On September 1, 2021, the Colorado Department of Health and Environment (CDPHE) issued a violation to the Town of Frisco for failure to install corrosion control treatment (CCT) systems at the Town’s water sources by the August 29, 2021 deadline. Testing of all four of Frisco’s water sources showed results below detectable levels, which indicated that elevated lead levels are not coming from Frisco’s water at the source. Instead, elevated lead levels are coming from the corrosion of older household plumbing materials and/or fixtures containing lead. The Town is currently in the process of installing the corrosion control systems at all each of the four water sources used by the Town, and Frisco’s water division anticipates complete installation of the CCT systems by the end of 2021.

Background and Timeline

In January 2019, during a routine six-month testing cycle for lead and copper, testing found that six homes out of the 40 tested had lead concentrations in exceedance of action levels (AL), the point at which treatment and other regulatory requirements are implemented. This includes installing corrosion control treatment (CCT), performing additional monitoring, replacing lead service lines (the Town of Frisco does not have any lead service or main water lines), and distributing public education materials to consumers about lead. As a result of the exceedances, the Town was required to study, recommend, and implement the CCT by August 29, 2021. By the end of January 2019, the Town of Frisco engaged with Plummer Engineering to perform a water study, and in June 2019, the Town received an optimal CCT recommendation based on this study.

In accordance with the Lead and Copper Rule, systems serving 50,000 or fewer people can discontinue the steps towards implementing a CCT whenever test results show levels are below action levels for two consecutive six-month monitoring periods. The June 2019 and January 2020 testing cycles showed results below action levels, but in July 2020, lead levels were found to have exceeded action levels, so the Town was required to recommence completion of the applicable corrosion control treatment steps from the point at which the process was paused.

There are several different chemical and mechanical methods a water system, such as the Town of Frisco, can use and each water system determines the best method available to reduce lead without causing the water system to violate any other part of the Colorado Primary Drinking Water Regulations. In January 2020, the Town consulted with stakeholders to determine the optimal CCT method and decided on chemical-based pH/Alkalinity adjustment.

  • On August 11, 2020, the Town signed an agreement with Plummer Engineering to design buildout of the CCT at all Town of Frisco water sources, and by January 2021, the Colorado Department of Health and the Environment (CDPHE) Engineering team reviewed and approved the design submission to bring the Town’s targeted operating pH range to 7.3-7.7 standard units (SU) based on the initial assessment study findings.
  • In March 2021, bid-ready documents were approved, and the water department engaged with the Town planning department to obtain permits for building modification. The Town of Frisco issued a request for proposals (RFP) on June 6, 2021, and in July 2021, the Town of Frisco awarded a bid to Velocity Plant Services.
  • During the latest round of testing (Summer 2021) for the Town of Frisco’s lead and copper monitoring, lead concentrations have again exceeded action levels in six homes/buildings out of 40 homes/buildings tested in Frisco.
  • Velocity Plant Services began ordering materials for this CCT project in August 2021; however, lead-times have been up to 12 weeks on critical items, including the chemical feed pumps and parts of the chemical feed system, static mixers, and valves. Velocity Plant Services will proceed with staging construction areas around the water treatment plant and valve houses so that they can start installation immediately once project materials arrive. The Town of Frisco water department anticipates that the CCT system will be in place by the end of 2021.

Currently, 156 systems in Colorado have pH adjustment in their treatment plants for various uses, not just for corrosion control. The corrosion control system that the Town of Frisco will install at each of Frisco’s four water sources will adjust the pH of the water by adding small, metered amounts of sodium hydroxide into the system. This puts the water into a more neutral to slightly alkaline state in order to prevent the lead and copper from dissolving into the water when in contact with fixtures and/or pipes in individual buildings.

About Sodium Hydroxide (NaOH)

Although sodium hydroxide is labeled a hazardous substance by the EPA due to its corrosivity, it is a highly versatile substance used in a variety of manufacturing processes for many products, including, medicines and pharmaceutical products, from common pain relievers like aspirin, to anticoagulants that can help to prevent blood clots, to cholesterol-reducing medications. Sodium hydroxide is also used in several food-processing applications, such as curing foods, removing skins from fruits and vegetables for canning, or as an ingredient in food preservatives that help prevent mold and bacteria from growing in food.

Municipal water treatment facilities, including Denver Water and Town of Dillon, commonly use sodium hydroxide to control water acidity and to help remove heavy metals, and the Town of Frisco already uses this substance for cleaning out water system filters.

How it Works

Potential hydrogen (pH) is an indicator of the acid or alkaline condition of water. The pH scale ranges from 0-14 with 7 indicating the neutral point. The normal pH range of drinking water is 6 – 8.5. The pH in any given water source is mostly a result of natural geological conditions at the site and the type of minerals found in the local rock. Water with a pH value less than 7 is acidic and tends to be corrosive.

Over time, acidic or even neutral water can leach toxic metals ions – predominantly lead – from pipes and solder that carry the water into and around buildings with old plumbing. Raising the pH of drinking water (making it more alkaline) makes the water less corrosive. This change also strengthens an existing protective coating on the interior of the pipes. The coating reduces the likelihood of lead getting into the water as it passes through household plumbing and faucets that contain lead.

Follow-up Monitoring

The EPA’s Lead and Copper Rule (LCR) requires systems to conduct two types of follow-up monitoring during the two consecutive, 6-month periods directly following installation of CCT:

Continuous lead and copper tap monitoring and water quality parameters monitoring. Water quality parameters are the specific ranges or minimums that represent the conditions under which the Town’s systems must operate their CCT to most effectively minimize the lead and copper concentrations at their users’ taps while not violating any other National Primary Drinking Water Regulations. The Town of Frisco water department will perform water quality checks for both source and mixed water every two weeks for the first six months the system is installed and compare them to results from samples collected prior to the system’s installation of CCT to determine if the system has properly installed and operated the CCT, and to set WQP. Currently, 45 systems in Colorado have pH optimal water quality parameters (OWQP) under the lead and copper rule.

Health Impacts of Lead

High levels of lead in drinking water can cause health effects if the lead in the water enters the bloodstream and causes an elevated blood lead level. Lead builds up in the body over time, so ongoing exposure, even at low levels, may eventually cause health effects. Infants and children are particularly susceptible to the health effects of lead because their bodies absorb lead at higher rates than the average adult does. Exposure to lead can result in:

  • Delays in children’s physical or mental development
  • Decreased IQ in children
  • Kidney problems
  • High blood pressure in adults
  • Lower birth weight infants

Strategies to Reduce Exposure to Lead in Water

While it is not recommended that water users seek alternative sources of water, there are steps that consumers can take to reduce exposure to lead in their water.

  • It is recommended that water users run their water to flush out lead. If the tap has not been used for several hours, cold water should be run until the temperature is noticeably colder. This flushes lead-containing water from the pipes. To conserve water, remember to catch the flushed tap water for plants or some other household use (e.g. cleaning).
  • Cold water only should be used for drinking, cooking and preparing baby formula.
  • Boiling water will not remove lead.
  • A faucet’s strainer/aerator should periodically be removed and cleaned, and while removed, water should remain running to remove debris.
  • Water users can test a home’s water for lead. The Town of Frisco will provide lead and copper test kits free of charge for Frisco residents in homes or buildings constructed in 1987 or earlier. A list of certified laboratories is provided at

More Information and action items for water customers

  • Please share this information with all the other people who drink this water, especially those who may not have received this notice directly (for example, people in apartments, nursing homes, schools, and businesses). You can do this by posting this notice in public places or by distributing copies by hand.
  • The Town continues to offer the Start at the Tap fixture rebate program, implemented in July 2019, to encourage homeowners to replace old fixtures in Frisco homes and buildings with WaterSense approved fixtures, which are more efficient and lead free.
  • Visit
  • Call or email Ryan Thompson, Water Supervisor- 970-668-9156 and
  • For more information on reducing lead exposure around your home/building and the health effects of lead, visit EPA’s website at


What is a corrosion control chemical?

A chemical that either alters the treated water chemistry or interacts with the surface of metallic materials in the water distribution system to inhibit corrosion and prevent the formation of soluble lead compounds.

Why is sodium hydroxide used in drinking water?

Sodium hydroxide is used as a pH adjusting chemical in the treatment of drinking water to control the corrosion of metals such as lead from pipes into the drinking water.

How does sodium hydroxide work?

Sodium hydroxide is used in the treatment of drinking water to raise the pH of the water to a level that minimizes the corrosion. Raising the pH remains one of the most effective methods for reducing lead corrosion and minimizing lead levels in drinking water.

Is it safe to drink my water if sodium hydroxide is added?

Yes. Sodium hydroxide use as a corrosion inhibitor is listed in NSF/ANSI Standard 60. These standards have been designed to safeguard drinking water by ensuring that additives meet minimum health effects requirements.

Why is sodium hydroxide the best choice as a corrosion inhibitor?

Sodium hydroxide was selected due to the chemistry and mineral makeup of the Town of Frisco’s raw source water and conditions in the distribution system (pipes). The water may leach minerals and contaminants from whatever material it comes into contact with. The addition of sodium hydroxide prior to transmission through distribution pipes will adjust the pH to a level that reduces this leaching capability of the water. As a corrosion inhibitor, sodium hydroxide is the best choice to treat our source water.

Will I be able to taste or smell sodium hydroxide in my tap water?

No. There will not be a difference in the taste or smell of your tap water.

Will the addition of sodium hydroxide in my drinking water have an adverse effect on the personal filter that I have installed?

No. However, for all privately-purchased water filtration systems it is recommended to always refer to the manufacturer’s instructions.

How will the addition of sodium hydroxide in our drinking water affect the treatment of waste water?

It is not expected that the addition of sodium hydroxide will affect the wastewater treatment process. The amount added will be small in relation to the many other substances found in raw sewage.