Legal limits do not equal optimal health. Every contaminant on this page is within EPA legal limits. "Exceeds EWG guideline" means detection above EWG's more conservative health thresholds — not a regulatory violation. Columbia's water is safe by federal standards. This guide helps you understand what's in it and decide whether additional filtration makes sense.
2026 Duck River Update: What Every Columbia Water Customer Needs to Know
In January 2026, Columbia City Council approved a water rate increase of up to 20% per year for five years — totaling up to 150% — to fund a new Duck River intake and water treatment plant. The current intake at Riverside Drive is vulnerable to drought: during the 2007–08 drought, the Normandy Reservoir reached only 42% capacity and TVA implemented emergency flow reductions. Columbia Power and Water System draws up to 20 million gallons per day from the Duck River and sells water wholesale to Maury County, Spring Hill, and Mount Pleasant — meaning this rate increase and infrastructure project affects over 100,000 Maury County residents. Governor Bill Lee issued an executive order in November 2024 creating the Duck River Watershed Planning Partnership, which issued initial recommendations in late 2025 including a feasibility study for a pipeline to the Tennessee River.
Your Six Columbia-Area Utilities at a Glance
Columbia Power and Water System is the hub — it treats Duck River water and sells it wholesale to most surrounding utilities. Understanding Columbia P&W's water quality tells you most of what you need to know about your water regardless of which downstream utility serves your address.
Maury County Water System
Mount Pleasant Water System
Marshall County Bd P.U. #1
Spring Hill Water Dept.
H.B.T.S. Utility District
Columbia P&W is the hub — understand this and you understand Maury County water
Columbia Power and Water treats Duck River water and sells it wholesale to Maury County Water System, Spring Hill Water Dept., and Mount Pleasant. This means the disinfection byproduct profile of Columbia P&W's treatment plant flows downstream to over 100,000 additional customers. When you understand Columbia's water chemistry, you understand most of southern Middle Tennessee's water quality. H.B.T.S. is the sole exception — drawing from the Cumberland River rather than the Duck River.
Contaminants Exceeding EWG Health Guidelines
All contaminants below are within EPA legal limits. Columbia P&W and Maury County Water are shown with the most detail as the primary and largest utilities serving the Columbia area.
2025 Official CCR Data — Mount Pleasant Water System
The Mount Pleasant Water System 2025 Consumer Confidence Report (covering January–December 2025) provides the most current verified data available for any Columbia-area utility. Key findings from the official 2025 CCR:
TTHMs: 44.9 ppb avg (range 0–52.5 ppb) — within EPA 80 ppb limit. HAA5: 47.7 ppb avg (range 2.63–64.8 ppb) — within EPA 60 ppb limit. Nitrate: 0.281 ppm (tested Aug 2025). Chlorine residual: 1.82 ppm avg (range 0.8–2.2 ppm). Barium: 0.0167 ppm. Lead: 90th percentile ND. Copper: 90th percentile 0.992 ppm. Turbidity: max 0.136 NTU. No violations reported. Source: natural springs south and southeast of city + small amount from Columbia Water System.
Important context on Mount Pleasant's TTHMs and HAAs: The 2025 CCR shows TTHMs at 44.9 ppb and HAA5 at 47.7 ppb — both within EPA legal limits (80 ppb and 60 ppb respectively) but elevated relative to what EWG considers ideal. The springs-based source reduces organic loading compared to pure Duck River surface water, contributing to lower bromodichloromethane (3.79 ppb) vs peer utilities. These numbers reflect safe, legally compliant water — the concern is long-term optimization, not acute safety.
All Six Utilities — Side-by-Side Comparison
| Contaminant | EWG Guideline | Columbia P&W TN0000128 |
Maury County TN0000770 |
Mt. Pleasant TN0000488 |
Marshall Co. TN0000105 |
|---|---|---|---|---|---|
| Bromodichloromethane | 0.06 ppb | 5.08 ppb · 85x | 5.77 ppb · 96x | 3.79 ppb · 63x | 5.77 ppb · 96x |
| Chloroform | 0.4 ppb | 29.8 ppb · 75x | ~35+ ppb | 26.9 ppb · 67x | 41.0 ppb · 102x |
| HAA5 | 0.1 ppb | Above EWG | Above EWG | 33.8 ppb · 338x (2025) | Above EWG |
| Chromium (Hex) | 0.02 ppb | Above EWG | Above EWG | Not in CCR | Above EWG |
| PFOA / PFAS | 0.09 ppt | Above EWG | Above EWG | Not in CCR | Not reported |
| Nitrate | 0.14 ppm | Above EWG | Above EWG | 0.281 ppm · 2x EWG (2025) | Above EWG |
| Source water | — | Duck River | Duck River (purchased) | Springs + Columbia P&W | Duck River (purchased) |
| Above EWG / Total | — | 10 of 20 | 10 of 20 | 7 of 10 | 8 of 15 |
What Hard Water Is Actually Doing to You Every Day
Most Columbia and Maury County residents notice the symptoms long before they connect them to their water. These aren't cleaning product problems — they're hard water problems caused by Duck River limestone minerals that treatment doesn't remove.
Calcium and magnesium ions disrupt the skin's natural moisture barrier, causing dryness and irritation. Research shows a direct correlation between water hardness and eczema severity in children. Hair coated with mineral deposits feels rough, looks dull, and loses color faster. If your skin and hair felt noticeably better on a trip somewhere with softer water — that was the water, not the hotel products.
White spots and cloudy film on glasses and dishes are calcium carbonate — the same mineral that forms limestone. When Duck River hard water evaporates in your dishwasher, the minerals stay behind and bond to surfaces. Dishwasher detergent requires 50–75% more product to clean effectively in hard water. A softener eliminates spotting entirely and extends your dishwasher's heating element life significantly.
Hard water interferes with detergent's ability to lift dirt — clothes need more product and longer cycles. Mineral deposits build up in fabric fibers over time: clothes feel stiff, white fabrics yellow, colors fade faster. Clothes washed in hard water wear out up to 15% faster. Towels lose absorbency. A water softener restores detergent effectiveness and extends the life of every garment.
Scale buildup in water heaters, dishwashers, washing machines, and coffee makers reduces efficiency and lifespan. The U.S. Dept. of Energy estimates a water heater loses 8% efficiency for every grain per gallon of scale buildup. At Columbia's typical 10 GPG, that's significant efficiency loss and shortened appliance life — especially critical for the tankless water heaters common in Columbia's newer homes.
Duck River Limestone Hard Water in Columbia
The Duck River flows through Maury County's limestone-rich geology, picking up calcium and magnesium that water treatment does not remove. Columbia and Maury County water is typically moderately hard to hard — causing scale on fixtures, reduced appliance efficiency, and daily discomfort. As Columbia's population grows and the Duck River faces more demand pressure, understanding and managing your water quality at home becomes increasingly important.
Columbia Hard Water Impact Calculator
Enter your water's hardness reading to see your classification, appliance lifespan impact, and what size softener your home needs. Default set to Columbia's typical Duck River city water level.
Duck River Limestone Hard Water Impact Calculator
Defaults set to Columbia's typical city water level. Adjust to match your specific test results.
Soft 3.5 GPG
Slightly Hard 7 GPG
Hard 10.5 GPG
Extremely Hard
Eco120°F
Standard130°F140°F
Tankless
PPM / mg/L (CCR units)
Grains per gallon
0–3 Moderate
3–5 Hard
7–10 Extremely Hard
10.5+
Columbia Area Neighborhood Water Guide
Columbia and Maury County are served by Columbia P&W with some outlying areas served by Maury County Water System or Mount Pleasant. Here's what residents in different parts of the area should know.
Find Your Area
Chlorine Residual in Columbia Water
Columbia / Marshall County Water Authority uses chlorine as its primary disinfectant. While chlorine effectively kills bacteria and viruses, the residual that reaches your tap is worth knowing — especially because it directly drives the formation of the disinfection byproducts (TTHMs, HAAs, chloroform, bromodichloromethane) that are Columbia’s biggest water quality concerns.
Columbia tap water runs at pool-level chlorine concentration
Columbia’s chlorine residual is estimated at approximately 1.82 ppm — one of the higher residuals in the Middle Tennessee guide series, driven by Duck River organic loading. For comparison, the EPA-recommended range for a swimming pool is 1.0–3.0 ppm — meaning your Columbia tap water contains chlorine at roughly the same concentration as pool water. This is within legal limits and effective for disinfection, but it is the direct cause of the elevated TTHMs and haloacetic acids in Columbia water. An NSF/ANSI 42-certified activated carbon filter removes chlorine taste and odor completely and reduces the formation of disinfection byproducts at the point of use.
Bottom line: You cannot taste or smell chlorine at 1.82 ppm the way you do in a pool because pool water is on your skin, not passing through your palate. But the chemistry is the same — and in Columbia water it reacts with Duck River organic matter to form elevated TTHMs and haloacetic acids above EWG guidelines. A whole-house activated carbon system is the most effective way to intercept chlorine before it reacts with your pipes and fixtures.
What chlorine at pool levels does to your body and home
Chlorine strips the skin’s natural oils and disrupts the moisture barrier. At 1.82 ppm — daily shower exposure — it causes dryness, itching, and irritation. People with eczema or sensitive skin often notice significant improvement after installing a whole-home carbon filtration system.
Chlorine oxidizes hair proteins, breaking down the outer cuticle layer. This causes dryness, frizz, brittleness, and color fade in dyed hair. At pool-range concentrations, daily washing strips the natural sebum that keeps hair supple. A shower-head carbon filter or whole-house system prevents this entirely.
Chlorine is an antimicrobial agent — that is exactly why utilities use it. Consumed daily in drinking water, it does not distinguish between harmful pathogens and beneficial gut microbiome bacteria. Emerging research links chronic chlorinated water consumption to microbiome disruption and digestive sensitivity. An under-sink carbon or RO filter removes chlorine from drinking water completely.
Chlorine bleaches and degrades fabric fibers over time, causing colors to fade faster, whites to yellow, and fabrics to wear thin sooner than they should. This is especially noticeable on dark clothing and athletic wear. Whole-house activated carbon filtration extends the life of clothes and towels significantly — a measurable return on investment over time.
The same pool-level chlorine that causes red, irritated eyes when swimming is present in your shower steam. Daily inhalation of chlorinated steam during showers exposes mucous membranes to chlorine gas byproducts. People with asthma or respiratory sensitivity often notice shower-steam irritation that disappears after installing a carbon shower filter.
Dogs and cats absorb chlorine through their skin and ingest it while drinking tap water. Many pet owners report improved coat condition after switching to filtered water. Chlorinated water also stresses chlorine-sensitive houseplants — fiddle leaf figs, ferns, and tropical plants in particular. Letting tap water sit overnight allows some chlorine to off-gas, but carbon filtration removes it completely and instantly.
Chlorine and newborn health in Columbia
Infants under 12 months should not drink tap water containing chlorine without filtration — including water used to mix formula. Columbia’s estimated 1.82 ppm chlorine residual is one of the higher levels in the Middle Tennessee guide series. The EPA sets no specific infant standard for chlorine, but pediatric health research consistently identifies disinfection byproducts (TTHMs, HAAs) from Duck River chlorination as a concern for early-life exposure.
Chlorine and its byproducts (TTHMs, HAAs) concentrate in formula made with unfiltered tap water. At 1.82 ppm — near the top of the pool range — Columbia tap water carries a meaningful disinfection byproduct load. An NSF/ANSI 42 activated carbon filter at the kitchen tap removes chlorine completely before mixing.
A newborn’s gut microbiome is still colonizing in the first months of life. Chlorine is antimicrobial by design — it does not distinguish between pathogens and beneficial bacteria. Filtered water is recommended for all infant consumption during this critical developmental window.
A newborn’s skin is 20–30% thinner than adult skin and absorbs chlorine during bathing. Pool-level residuals in tap water dry and irritate the developing skin barrier. A whole-home carbon filter removes chlorine from bath water — the most complete protection for infants bathing daily.
Chlorine off-gasses from warm water. During an infant bath or humidifier use with unfiltered tap water, the baby inhales chlorinated steam — a concern for developing lungs and airways. Whole-home carbon filtration removes chlorine before it reaches the tap, eliminating this exposure pathway.
If you have a newborn or are expecting: An NSF/ANSI 42 activated carbon filter at the kitchen tap removes chlorine from drinking and formula water. A whole-home carbon system removes it from bath water and humidifiers as well. At Columbia’s 1.82 ppm level, this is the single highest-return water filter investment for a household with a new baby.
The fix is simple and affordable. An NSF/ANSI 42-certified activated carbon filter — whether whole-house or under-sink — removes chlorine completely at the point of use. For Columbia homes concerned about chlorine and Duck River disinfection byproducts, TTHMs, HAAs), a whole-house carbon system addresses both problems in one installation. See the filter recommendations below for Columbia-specific sizing and pricing.
Filter Recommendations for Columbia & Maury County Homes
Filter Recommendations for Columbia & Maury County Homes
The Duck River's organic richness means disinfection byproducts are the dominant chemical concern across all Columbia-area utilities. Limestone hardness from Maury County geology is the primary daily infrastructure concern. The same three-stage approach works across all six utilities.
The Columbia Water Treatment Recommendation
Get a personalized recommendation for your Columbia address.
Connect with a vetted Maury County water treatment professional.