Get the Facts About Oklahoma City Water Quality in 2024

Where Does Oklahoma City’s Tap Water Come From?

Oklahoma City’s tap water comes from several surface water sources outside of the city. To the northwest, rainwater is stored in the Canton Reservoir and flows along the North Canadian River before it’s treated at the Hefner Reservoir closer to the city.

To the southeast, it collects in the Atoka and McGee Creek Reservoirs before it’s carried along a 100-mile pipeline to the Stanley Draper Reservoir for treatment.

Since the water starts off as rain, it accumulates “naturally occurring minerals found in rocks and soil, plus pesticides or herbicides used in farming, and bacteria from human or animal activity,” according to the most recent Drinking Water Quality Report.

These contaminants need to be treated or removed to meet the U.S. Environmental Protection Agency (EPA)’s guidelines under the Safe Drinking Water Act.

How Is Oklahoma City’s Drinking Water Treated?

The Oklahoma City Water Utilities Trust maintains two treatment plants that process as many as 40 billion gallons of water per year. Like other American water systems, OKC uses a combination of filtration to remove microorganisms and other contaminants, as well as disinfection to kill any viruses or bacteria that remain.

According to the Consumer Confidence Report (CCR), OCWUT conducts tests at both plants and at 260 sites throughout the system. They provide the results each month to the Oklahoma Department of Environmental QUality (ODEQ).

Although OKC’s water supply meets the guidelines of the EPA and the DEQ, tests do show concerning levels of some contaminants, including disinfection byproducts.

Is Oklahoma City’s Drinking Water Fluoridated?

Yes, OCWUT adds fluoride to the drinking water as a public health measure. The U.S. Public Health Service recommends a maximum concentration of 0.7 milligrams per liter (mg/L) to prevent tooth decay. Oklahoma City tests fluoride levels every 12 hours, with average readings hovering just at or below the recommended levels.

What Contaminants Are Found in Oklahoma City’s Drinking Water?

Unwanted contaminants can affect the water supply in a number of ways. These include naturally occurring minerals found in source water supplies (freshwater or groundwater); wastewater discharge and stormwater runoff; and disinfection byproducts, or chemicals that remain when chlorine and ammonia is used in the water treatment process.

Here are five key contaminants of concern affecting Oklahoma City water quality, along with the potential health effects of each.

1. Total trihalomethanes (TTHMs)

Trihalomethanes are four byproducts of the disinfection process. These chemicals have been linked to skin cancer, bladder cancer, and harm to fetal growth.

Although the EPA’s legal limit for total trihalomethanes is 80 parts per billion (ppb), the Environmental Working Group (EWG) recommends a stricter limit of 0.15 ppb, which Oklahoma City’s tap water exceeds by 348 times:

• EPA maximum allowance: 80 ppb
• EWG recommended maximum: 0.15 ppb
• Oklahoma City maximum contaminant level: 52.2 ppb

2. Haloacetic acids (HAA5)

Haloacetic acids are another group of chemicals formed in the disinfection process that have been linked to cancer and harm to fetal growth. The EPA sets an upper limit of 60 ppb for five haloacetic acids (known as HAA5), but the EWG recommends a limit of 0.1 ppb, which OKC’s water quality exceeds by 297 times:

• EPA maximum allowance: 60 ppb
• EWG recommended maximum: 0.1 ppb
• Oklahoma City maximum contaminant level: 29.7 ppb

3. Haloacetic acids (HAA9)

HAA9 refers to a group of nine disinfection byproducts — HAA5, plus four more. When measured this way, there’s no legal limit for contamination levels, but these chemicals are linked to some of the same health effects as HAA5.

Texas and California have more utilities with HAA9 contamination than any other state, but Oklahoma has some of the highest levels of HAA9 contamination overall. OKC’s water system exceeds the EWG’s recommendation by 635 times:

• EPA maximum allowance: No legal limit
• EWG recommended maximum: 0.06 ppb
• Oklahoma City maximum contaminant level: 38.1 ppb

4. Chromium (hexavalent)

Hexavalent chromium, or chromium-6, is a chemical that can contaminate water from natural sources, or from industrial pollution. At high levels, it can have severe health effects — as evidenced by Erin Brokovich’s famous court battle in Hinkley, CA.

Since there’s no legal limit for hexavalent chromium set by the EPA, we can use the EWG’s recommendation as a guide to Oklahoma City water quality:

• EPA maximum allowance: No legal limit
• EWG recommended maximum: 0.02 ppb
• Oklahoma City maximum detected level: 0.115 ppb

5. Bromate

Bromate is another cancer-causing chemical that’s formed in the disinfection process. California has set a Public Health Goal for bromate levels in drinking water of 0.1 ppb, but the EPA’s maximum allowance is significantly higher, at 10 ppm. OKC’s bromate levels exceed the public health goal by 14 times:

• EPA maximum allowance: 10 ppb
• EWG recommended maximum: 0.1 ppb
• Oklahoma City maximum contaminant level: 1.37 ppb

Does OKC Tap Water Have Forever Chemicals?

Forever chemicals, or PFAS, are a category of man-made chemicals used in industrial settings, as well as at military bases and airports. Until recently, these chemicals haven’t been widely tested for or even regulated by the EPA, but a new rule called the National Primary Drinking Water Regulations (NPDWR) intends to change that.

The Oklahoma City Utilities Department has begun testing for PFAS in the water supply, and reports that “all sample results for the forever chemicals regulated in the NPDWR have been below 4 ppt.” However, according to “The Oklahoman,” at least four water systems in the area have detectable levels of one or more PFAS pollutants.

Should You Filter Oklahoma City Tap Water Before Drinking It?

As you can see, many of the contaminants affecting Oklahoma City water quality aren’t unique to Oklahoma’s water sources, but are the result of the water treatment process. Other contaminants found at lower levels include nitrates and nitrites — typically from fertilizer runoff — and arsenic, a heavy metal that can cause arsenic toxicity.

Levels of some contaminants are high compared to other American water systems, so you may be wondering whether to install a water filter or drink bottled water. Activated carbon filters and reverse osmosis filters can remove contaminants, but you’ll want to check the NSF rating of your filter to see what it’s designed for.

The advantage of under-sink water filters is that they’re easy to install, and you can simply change the filter when it’s time to replace it. Bottled water, on the other hand, may be no safer than tap water, and may still contain contaminants like PFAS.

Does Oklahoma City’s Drinking Water Contain Lead?

Lead pipes in homes are a hidden danger — not just in OKC, but in all American water systems. Although Oklahoma City’s drinking water doesn’t contain lead, it can pick up lead along the way as it moves through the distribution system.

According to OKC.gov, none of the city’s water mains contain lead, but some service lines and pipes could contain lead, especially in buildings built prior to 1945.

In 2023, the Oklahoma City Utilities Department inventoried 8,500 service lines and plans to continue checking and replacing city-owned service lines that contain lead. Homeowners are responsible for replacing privately owned service lines.

In the meantime, you can test your tap water for lead and use an NSF 53 filter that’s certified to remove lead from your drinking water.

What Is Oklahoma City Doing to Protect Its Water Quality?

Improving tap water quality starts with source water protection — that is, monitoring the watersheds where the water originates and protecting them from contamination.

The Urban Waters Learning Network explains how the Oklahoma City watershed is at risk of eutrophication, a lack of oxygen linked to algal blooms that’s usually caused by fertilizers, animal waste, and other pollutants entering the water system.

The Oklahoma Comprehensive Water Plan takes the long view, with a 50-year plan for monitoring water quality and increasing water resiliency in Oklahoma. Ultimately, the goal is to consume “no more fresh water in 2060 than was consumed in 2010.”

Is Oklahoma City’s Tap Water Safe to Drink?

Oklahoma City’s tap water is tested and treated before it’s distributed, and according to the latest Consumer Confidence Report, it meets the water quality requirements of the EPA and the Oklahoma DEQ. Residents can feel reasonably confident that it doesn’t contain unsafe levels of viruses or bacteria when it leaves the treatment plant.

However, not all contaminants are regulated by the EPA, and the treatment process itself can introduce chemical byproducts like haloacetic acids and THMs.

To reduce your exposure to PFAS, heavy metals, and other contaminants, use a home filtration system like the UPSTREAM™ 4-Stage Whole Home Water Filter, which uses red flint, KDF55, and catalytic carbon to remove unwanted contaminants.

Still not sure which filter is right for you? Enter your ZIP code to see your local water quality report and find out exactly what’s in your water.