Get the Facts About Louisville, KY Water Quality Data

Where Does Louisville, KY’s Drinking Water Come From?

Louisville, KY’s tap water is provided by the Louisville Water Company, which was first formed in 1860 to serve a total of 512 customers. Over the next century, it refined its process to develop its own trademarked tap water called Louisville Pure Tap®.

According to the Louisville Water Company’s Annual Water Quality Report, the tap water in Louisville comes primarily from the Ohio River. It processes the water at the Crescent Hill Water Treatment Plant and delivers it to residents of the Louisville metro area and several nearby counties — reaching as many as one million people.

It has another treatment plant in Jefferson County — the B.E. Payne Water Treatment Plant — which collects and processes groundwater instead. The Louisville Aquifer is estimated to contain as much as 7 billion gallons of water deep underground.

How Clean Is Louisville, Kentucky’s Water Supply?

Both of Louisville’s water sources are treated to meet the water quality standards of the U.S. Environmental Protection Agency (EPA). But how clean is it to begin with?

Historically, the Ohio River has had major problems with pollution, with some reports calling it the most polluted river in the country. According to WOSU, this is due to a combination of “legacy stormwater systems and heavy agricultural use.”

These days, thanks to efforts to reduce wastewater and agricultural runoff, the Ohio River is significantly less polluted than it used to be. The Louisville Water Company maintains a Source Water Area Protection Plan (SWAPP) and Wellhead Protection Plan, and the Kentucky Energy and Environment Cabinet oversees source water protection throughout the state.

Water utilities are required to issue a Consumer Confidence Report so residents know what’s in their water — although this can be hard to interpret. We’ll take a look at the latest news and Louisville, KY water quality data to help you make sense of it.

You can also get a free water quality report that’s specific to your ZIP code.

How Is Louisville’s Drinking Water Treated?

Louisville, KY, uses a different treatment method for each of its two water sources. The Crescent Hill Water Treatment Plant on the Ohio River uses the following four steps:

• Coagulation: This step uses chemicals to cause small particles such as clay and silt to clump together for easy removal.
• Sedimentation: In this step, the larger clumps of particles settle to the bottom of the tank and are filtered out of the water.
• Disinfection: Louisville Water adds chlorine and ammonia to kill microorganisms that cause waterborne diseases, such as cryptosporidium.
• Filtration: Finally, they use anthracite coal and sand filters to get rid of additional particles that made it through the other stages of treatment.

The B.E. Payne Water Treatment Plant uses a different water treatment process called riverbank filtration. This plant has a 1.5-mile-long underground tunnel that uses gravity to naturally filter groundwater from the aquifer through layers of gravel and sand.

How Is Louisville, KY’s Water Quality Tested?

Louisville Water conducts 200 water tests per day to identify any water quality concerns and address any risks to public health. Louisville, KY water quality has a pH level of 8.7 and a hardness level of 7.9 grains per gallon, considered moderately hard water.

It also has 228 parts per million (ppm) of total dissolved solids (TDS), which can include minerals, salts, and organic matter. This TDS level is considered relatively low.

As of 2023, Louisville began adding chlorine dioxide as an additional disinfectant, which could impact people on dialysis and customers with fish tanks.

Which Contaminants Are Found in Louisville’s Tap Water?

When it leaves the treatment plants, Louisvilliains can feel confident that their drinking water isn’t contaminated with germs, bacteria, or viruses. But it may still contain other contaminants that are formed in the treatment process or found in the source water. Here are five potential contaminants of concern found in Louisville tap water.

Chromium-6 (hexavalent)

Chromium-6 is a cancer-causing chemical made famous by Erin Brockovich in Hinkley, California. Although the EPA has a legal limit for total chromium levels, it doesn’t have any specific limit for chromium-6, which is present in some American water systems.
The Environmental Working Group (EWG), a nonprofit, recommends an upper limit of 0.02 parts per billion (ppb), which Louisville Water exceeds by 4 times:

• EPA maximum allowance: No legal limit
• EWG recommended maximum: 0.02 ppb
• Louisville maximum contaminant level: 0.0806 ppb

Haloacetic acids (HAA9)

Haloacetic acids are a group of disinfection byproducts that arise during the disinfection process. The more disinfectants are added, the more haloacetic acids are formed.

These acids are measured in two groups (HAA5 and HAA9), both of which are found in Louisville drinking water. Although the EPA hasn’t set a legal limit for HAA9, Louisville’s tap water exceeds the EWG’s recommendation by 459 times:

• EPA maximum allowance: No legal limit
• EWG recommended maximum: 0.06 ppb
• Louisville maximum contaminant level: 27.5 ppb

Nitrate and nitrite

Nitrate and nitrite are chemicals that cause cancer and harm to fetuses when ingested in large quantities. They get into the water supply from agricultural and urban sources, such as fertilizer runoff and sewage discharge.

Nitrate and nitrite levels in Louisville water are below the EPA’s legal limit, but 5.1 times higher the EWG’s public health recommendation:

• EPA maximum allowance: 10 parts per million (ppm)
• EWG recommended maximum: 0.14 ppm
• Louisville maximum contaminant level: 0.714 ppm

Perfluorooctanoic acid (PFOA)

Perfluorooctanoic acid (PFOA) is a forever chemical that the EPA is just beginning to regulate, along with PFOS and other types of PFAS. These chemicals are found in consumer goods like non-stick cookware, and can have long-term health effects.

The EPA has set a proposed limit of 4 parts per trillion (ppt), but the EWG recommends a more cautious limit of 0.007 ppt. Louisville tap water exceeds it by 672 times:

• EPA maximum allowance: 4 ppt (proposed limit)
• EWG recommended maximum: 0.007 ppt
• Louisville maximum contaminant level: 4.71 ppt

Total trihalomethanes (TTHMs)

Trihalomethanes form another category of disinfection byproducts that’s measured as a group (total trihalomethanes, or TTHMs). Over time, consuming TTHMs in drinking water can increase the risk of cancer and other health conditions.

Louisville’s TTHM levels are below the legal limit, but 146 times higher than what the EWG recommends as a safe threshold:

• EPA maximum allowance: 80 ppb
• EWG recommended maximum: 0.15 ppb
• Louisville maximum contaminant level: 21.9 ppb

Can Water Filters Improve Louisville, KY’s Water Quality?

Louisville’s drinking water is filtered and disinfected before it comes out of your tap — but does that mean it’s safe to drink as-is or should you filter it further? A home water filter can help you remove some additional contaminants from your water supply.

Activated carbon filters are a good choice if you want to remove disinfection byproducts and improve the taste of your tap water. Reverse osmosis filters are more effective at removing PFOA and other forever chemicals, although they can be expensive.

At the budget end of the spectrum, you can install an under-counter filter below the tap you use most, such as your kitchen sink. For more extensive filtration, install a whole home water filter that covers everything, including your shower and refrigerator.

Does Louisville’s Tap Water Contain Lead?

Like many American cities, the city of Louisville is trying to raise awareness about lead, but the issue isn’t with the tap water — it’s with lead pipes and service lines. Louisville’s drinking water is lead-free when it leaves the treatment plant, but it can pick up lead along the way if it passes through lead service lines or plumbing fixtures.

According to Louisville Public Media, up to “800 of the city’s older homes still have private lead service lines.” While many cities place the burden on homeowners to replace private service lines, Louisville Water will replace them for free.

If your home was built before 1950 and you suspect it has a lead service line, you can use the Private Service Line Lookup tool to find out. Homes built after 1950 but before 2014 could still have lead pipes or plumbing fixtures, so consider testing your tap water for lead. Louisville Water will send you a free mail-in lead test kit upon request.

Is Louisville, KY’s Tap Water Safe to Drink?

Louisville, Kentucky’s tap water is considered safe to drink according to the standards of the EPA. In fact, the city’s water system ranks highly compared to other American cities. However, Louisville’s water treatment process results in high concentrations of disinfection byproducts, and the source water may contain high levels of PFOA and other forever chemicals that are known to have adverse health effects.

A home water filter can go a long way toward removing unwanted contaminants and improving the taste and quality of Louisville tap water.

With the HomeWater EZChange filter system, it’s easy to install an under-counter water filter and ensure you’re always drinking high-quality water. In fact, subscribers get 15% off with a filter subscription. Shop under-counter water filters at HomeWater today!