Terre Haute, Indiana, sits on the east bank of the Wabash River in the western part of the state. Home to about 60,000 people, Indiana State University, and a history tied to coal, manufacturing, and transportation, Terre Haute has the kind of industrial background that makes water quality a legitimate concern.
The city draws its drinking water from the Wabash River — Indiana’s longest river and one that collects agricultural runoff, industrial discharge, and treated wastewater from communities along its 500-mile journey from northeastern Indiana to its confluence with the Ohio River.
The Wabash River’s Water Quality
The Wabash River has been identified as one of Indiana’s most impaired waterways. Multiple segments appear on the state’s 303(d) list of impaired waters under the Clean Water Act. Key issues include:
- Nutrient loading — Nitrogen and phosphorus from agricultural runoff (fertilizers, animal operations) drive algal growth and oxygen depletion. Indiana is one of the top agricultural states, and the Wabash watershed is heavily farmed.
- E. coli and pathogens — Bacterial contamination from agricultural runoff, combined sewer overflows, and failing septic systems.
- Sediment — Erosion from agricultural fields contributes high sediment loads that affect water clarity and carry attached contaminants.
- Pesticides and herbicides — Atrazine, metolachlor, and other agricultural chemicals are regularly detected in the Wabash and its tributaries. USGS monitoring has shown seasonal spikes correlated with spring planting and application.
For a city drinking from this river, the treatment plant works hard.
Coal Ash: A Regional Contamination Source
Indiana generates a significant portion of its electricity from coal-fired power plants, and coal ash — the waste left after burning coal — is a major environmental issue in the region.
Coal ash contains heavy metals including arsenic, selenium, boron, molybdenum, mercury, cadmium, and chromium. When stored in unlined ponds or landfills (which was standard practice for decades), these metals can leach into groundwater and surface water.
In the Terre Haute area, the Wabash Valley Power Association and Duke Energy have operated coal-fired plants with associated ash disposal facilities. Across Indiana, the EPA and environmental groups have documented groundwater contamination at numerous coal ash disposal sites.
The EPA’s 2015 Coal Combustion Residuals (CCR) Rule required utilities to monitor groundwater near coal ash impoundments and take corrective action if contamination is found. Data from these monitoring programs has revealed widespread groundwater exceedances for arsenic, lithium, molybdenum, and other metals at Indiana coal ash sites.
While these groundwater contamination plumes don’t necessarily reach Terre Haute’s drinking water intake directly, they contribute to the broader degradation of water resources in the Wabash Valley.
Current Drinking Water Quality
The Terre Haute Water Works draws from the Wabash River and operates a conventional treatment plant with coagulation, flocculation, sedimentation, filtration, and chlorine disinfection.
Recent water quality data shows:
- The system meets EPA primary drinking water standards for regulated contaminants.
- Atrazine — This common herbicide has been detected in treated water, though at levels below the EPA MCL of 3 ppb. Seasonal spikes during spring planting season are typical for Midwest river systems.
- Disinfection byproducts — Trihalomethanes and haloacetic acids are present at detectable levels. The high organic content of the Wabash River (from agricultural runoff) makes DBP management a constant challenge for the treatment plant.
- Nitrate — Agricultural nitrogen loading in the watershed means nitrate is a concern, though levels in treated water have remained below the EPA MCL of 10 ppm.
- Lead and copper — The system monitors under the Lead and Copper Rule. Older homes in Terre Haute may have lead service lines or lead solder, and lead at the tap can exceed safe levels in these homes even when the treated water leaving the plant contains essentially no lead.
PFAS: What’s Coming
Indiana has been conducting PFAS sampling across the state’s public water systems. The federal PFAS standards finalized in 2024 (4 ppt for PFOA, 4 ppt for PFOS) will require all community water systems to test and report.
Potential PFAS sources in the Terre Haute area include:
- Terre Haute Air National Guard Base — Military facilities nationwide have been identified as PFAS contamination sources due to AFFF firefighting foam use.
- Industrial facilities — Manufacturing operations that used PFAS-containing materials.
- Wastewater treatment plants — Upstream WWTPs that receive PFAS from residential and commercial sources and pass it through to the river.
The results of PFAS testing will be important for Terre Haute residents. The city’s reliance on the Wabash River as its sole drinking water source means any contamination in the river directly challenges the treatment system.
Aging Infrastructure
Like many Midwest cities, Terre Haute faces infrastructure challenges:
- Water mains — Some date to the early 1900s. Aging mains can break, allowing contamination to enter the distribution system, and can develop biofilm that harbors bacteria.
- Lead service lines — The city has been conducting its required lead service line inventory. Homes built before 1950 — which describes a large portion of Terre Haute’s housing stock — are most likely to have lead connections.
- Combined sewer overflows (CSOs) — During heavy rain, Terre Haute’s combined sewer system can overflow, discharging untreated sewage into the Wabash River upstream of the drinking water intake. This is a recognized problem that the city has been working to address through a long-term control plan.
What Residents Can Do
- Test for lead at the tap. Contact Indiana American Water (if they’re your provider) or the Terre Haute Water Works for information on testing programs. Homes built before 1950 should be priorities.
- Flush your tap before drinking if water has been sitting in pipes for several hours. Run cold water for 30 seconds to two minutes.
- Consider a point-of-use filter. A filter certified to NSF/ANSI 53 can reduce lead, atrazine, and some disinfection byproducts. For broader protection including PFAS, reverse osmosis (NSF/ANSI 58) is the best option.
- Use cold water for cooking. Lead dissolves more readily in hot water.
- Review the annual water quality report. Look at the actual numbers, especially for atrazine, DBPs, and nitrate. These are the contaminants most likely to be elevated in a Midwest river system.
- Private well owners: If you’re outside the city water system, test annually for nitrate, bacteria, atrazine, and metals. Consider adding PFAS to your testing panel.
The Bottom Line
Terre Haute’s water meets federal standards, but the city faces a challenging combination: an agriculturally and industrially impacted source river, aging distribution infrastructure, and emerging contaminants like PFAS on the horizon.
The Wabash River carries what Indiana puts into it — fertilizers, pesticides, treated wastewater, and whatever leaches from coal ash sites and industrial properties along its banks. The treatment plant is the last line of defense, and it works. But residents benefit from understanding what’s in the source water and taking steps to protect themselves at the tap.
If you’re concerned about your water quality, a certified water treatment professional can test your water and advise on solutions tailored to your specific situation.
Sources: Indiana DEP 303(d) Impaired Waters List, EPA Coal Combustion Residuals Rule monitoring data, Terre Haute Water Works Consumer Confidence Reports, USGS National Water-Quality Assessment (NAWQA) Program Wabash River studies, EPA PFAS National Primary Drinking Water Regulation (2024).