Norman Water Quality: Information of Interest

Lead and Copper

What is it?

Lead and Copper are naturally occurring metals commonly used in plumbing materials prior to 1986 that have the potential to leach out into drinking water.

Why do we care?

While copper is an essential nutrient required for a healthy diet in small amounts, it can have negative health effects, such as gastrointestinal distress, before any excess can be secreted from the body.

Lead, on the other hand, is dangerous at all levels if ingested, and can accumulate in bones. This is especially concerning for growing infants and children, as it can affect their IQ, contribute to learning disabilities, impair growth, and damage the brain and kidneys.

The Lead and Copper Rule was developed in 1991 to protect the public from ingesting these compounds.

What are the limits of Lead and Copper in drinking water?

The current limits under the 1991 rule requires less than or equal to a 90th percentile of 1.3 mg/L for Copper and 15 ug/L for Lead.

A new rule (the Lead and Copper Rule Revisions) is on its way and is set to take effect in October 2024. This rule will require the same action limits mentioned above, but will also include additional trigger levels for lead between 10-15 ug/L that will require additional action from the water system if found. In addition to a trigger level, this rule will require sampling in schools and day care facilities, as well as a public inventory of all known service lines and their material. This page will be updated when addition information required by the new rule is made available.

How do I know if lead and copper has been found in my drinking water?

Lead and Copper sampling is required from homes within the distribution system. In order to be on the City’s list for Lead and Copper sampling, your address must be a location built before 1991 (before the lead ban was adopted) with plumbing that has not been updated since development. In addition, your home/individual faucets cannot have a treatment system such as a filter or RO system.

You, the homeowner/tenant, must be willing to collect the sample by following written sampling instructions, and providing the sample to the City within one week after collection.

The City is required to obtain 55 samples per monitoring period and submit these samples to the Oklahoma Department of Environmental Quality. Compliance lead and copper sample results can be found here. Since the start of lead and copper monitoring following the establishment of the 1991 rule, the City of Norman has not had any lead and/or copper exceedances, indicating operations at the treatment plants are working properly.  

How can I prevent lead and copper exposure?

The best way to prevent lead exposure is to find and replace all lead service lines in the city.  Therefore, the City is actively working on replacing all known locations of lead service lines on the public side when funding and time allows.

In addition, Corrosion Control Treatment processes conducted at the Water Treatment Plant involve the addition of chemicals that coat the inside of waterlines, acting as barrier so lead stays attached to the waterline and doesn’t dissolve into your water. Further, the Water Treatment Plant adjusts the pH of the water to ensure that the stability of the water does not become corrosive.

If disturbances to a known public lead service line are made by the City due to line replacements, staff will provide your home with a pitcher, with enough filters to last 6 months. This is because, unlike contaminants like bacteria, metals cannot be removed by boiling. Any water used for consumption must be ran through a filter designed to remove lead.

Where can I learn more about Lead and Copper?

Additional information regarding lead and copper can be find on the EPA's website.


What is it?

Arsenic is a naturally occurring metal found in soil and groundwater across the globe. While arsenic can be generated by manufacturing processes, the Arsenic found in the Garber-Wellington Aquifer in Norman, OK is naturally occurring in existing bedrock formations.

Arsenic enters groundwater through the natural percolation of water into aquifers. Aquifers can have differing levels of naturally occurring arsenic based on location.

Why do we care?

Long-term exposure to high levels of arsenic can increase the risk to certain types of cancer, heart disease, and diabetes.

What is the limit for Arsenic in drinking water?

In 2006, the EPA established an arsenic limit in drinking water at 10 ug/L (ppb). Before this date, the limit was 50 ppb. Many groundwater wells being utilized in Norman at that time were then required to be treated to remove the arsenic, or inactivated (not used) by the City.

The City of Norman has one well currently being treated for Arsenic by using Bayoxide, an adsorptive filter media. This system was established in 2009 after a pilot was conducted on the well to determine its feasibility. It has been running annually since and water entering the distribution system from this well has continued to meet the 10 ug/L MCL required by the EPA and DEQ. Various articles have been published in scientific journals that detail the pilot process conducted on this well and it has been used widely as an example of effective, full-scale arsenic treatment for other utilities.

How can I find out if there is Arsenic in my drinking water?

The City of Norman public water system meets or exceeds all federal and state regulations regarding arsenic and conducts routine arsenic testing on all groundwater wells owned by the City. This information can be found on our latest Consumer Confidence Report.

Where can I learn more about Arsenic?

Additional information regarding arsenic can be find on the EPA's website.


What is it?

Chromium is a naturally occurring element found in the environment. While chromium in drinking water can come from manufacturing processes, all of the Chromium found in the Garber-Wellington Aquifer in Norman, OK is naturally occurring in existing bedrock formations.

Chromium enters groundwater through the natural percolation of water into aquifers. Aquifers can have differing levels of naturally occurring Chromium based on location.

Why do we care?

Most chromium in its trivalent form is harmless, and is even an essential element in humans, however, hexavalent chromium in large amounts could have the potential to harm the kidney and liver, cause certain types of cancers, and irritate the eyes, skin, and respiratory system.

It should be noted that the body has the ability to detoxify some amounts of hexavalent chromium by converting it to its nontoxic, trivalent state, making regulation for this constituent tricky.

What is the limit for Chromium in drinking water?

The EPA has a total chromium maximum contaminant level of 100 ug/L (ppb). There is no individual limit for trivalent chromium or hexavalent chromium at this time. Total chromium has been argued as being more conservative by combining the levels of both trivalent chromium and hexavalent chromium.

The EPA is currently conducting studies to determine whether or not a separate hexavalent chromium limit should be established, or whether or not the existing total chromium limit needs to be lowered.

The City has been proactive by conducting numerous pilot projects aimed at treating chromium in drinking water using varying methods over the last 10 years. Articles based on the success of these pilots have been published in various scientific journals, such as American Water Works Association (AWWA) Water Science.

The data from these pilots will be used by the City to establish the most economical and efficient treatment for our groundwater if the limit is lowered, or a new hexavalent chromium limit is established. 

How can I find out if there is Chromium in my drinking water?

The City of Norman public water system meets or exceeds all current federal and state regulations regarding chromium and conducts routine total chromium testing on all active groundwater wells. This information can be found on our latest Consumer Confidence Report.

Where can I learn more about Chromium?

Additional information regarding chromium can be find on the EPA's website.


What is it?

PFAS stands for Per- and Poly-Fluorinated Alkyl Substances. Common forms are PFOS and PFOA.

Theses compounds are known as “forever chemicals” due to their ability to last very long periods in the environment before being broken down.

They have been used widely in manufacturing since the 1960s and can be found in many items, such as non-stick pans, food wrappers, stain-resistant clothing, fire-fighting foams, cleaners, and other materials that are designed to resist water, oil, grease, and heat.  Because of their widespread use and persistence in the environment, many PFAS are found in the blood of people and animals all over the world and are present at low levels in a variety of products and the environment.

Why do we care?

Exposure to some PFAS in the environment may be linked to harmful health effects in humans and animals such as high blood pressure, high cholesterol, and liver damage.

There are thousands of PFAS chemicals, and many more being developed by manufacturers every day, making it challenging to slow down their persistence in the environment and study their effects on human health and environmental risks.

What are the limits of PFAS in drinking water?

The EPA is working on a final Maximum Contaminant Level (MCL) for both PFOA and PFOS. An MCL of 4.0 parts per trillion (ppt or ng/L) was proposed in March 2023.

Other compounds, known as GenX chemicals (PFNA, PFHxS, PFBS, and HFPO-DA), have a proposed Hazard Index of 1.0.

Has there been PFAS found in my drinking water?

Under the third Unregulated Contaminants Monitoring Rule (UCMR3) conducted in 2016, the City of Norman tested various locations for PFAS chemicals. All results indicated that PFAS were not detected in any of the samples taken at the reporting limit used at that time.

The City of Norman will start collecting samples for the fifth Unregulated Contaminants Monitoring Rule (UCMR5) in 2023. This study will involve testing for 29 PFAS compounds that will help EPA determine future regulations and other actions to protect public health under the Safe Drinking Water Act. Once these results are available, the data will be made public.

The City of Norman will be conducting additional testing if, and when, the EPA sets a final MCL for any PFAS compounds.

Where can I learn more about PFAS?

Additional information regarding PFAS can be find on the EPA's website.


For additional information regarding these compounds, contact the Water Treatment Plant at 405-321-2182.