Legal limits do not equal optimal health. All contaminants on this page are within EPA legal limits on an annual average basis. EWG exceedances reflect EWG’s more conservative health thresholds — not regulatory violations. Nolensville-area water is legally safe to drink.
NCGUD: TTHMs at 77.53 ppb LRAA — highest of any utility in this guide series
The Nolensville/College Grove Utility District’s 2024 CCR confirms total trihalomethanes at 77.53 ppb highest LRAA (range 37.20–81.80 ppb). The EPA’s limit is 80 ppb. The highest quarterly measurement of 81.80 ppb exceeded that limit. The official annual LRAA of 77.53 ppb remains within compliance and the utility reports no violation. NCGUD purchases from multiple sources — Metro Nashville and Town of Smyrna — and TTHMs continue building in the distribution system after treatment. A whole-house activated carbon filter is the single most impactful water quality investment available for Nolensville and College Grove residents.
2024 Official CCR Data — Nolensville/College Grove Utility District
NCGUD’s 2024 Water Quality Report is the most current verified data for Nolensville and College Grove residents. Water is purchased from Metro Nashville (surface water, Cumberland River) and Town of Smyrna (surface water, Rutherford County). TDEC SWAP: reasonably susceptible to potential contamination.
range 37.20–81.80 · EPA limit: 80 ppb
range 19.40–46.80 · EPA limit: 60 ppb
Lead 90th%: <2.00 ppb (2022)
10 contaminants detected, all safe
Sources: Town of Smyrna (surface water), Metro Nashville (surface water). TDEC SWAP: reasonably susceptible. TTHMs 2024: 77.53 ppb highest LRAA (37.20–81.80) — highest of any utility in this guide. HAA5: 36.55 ppb LRAA (19.40–46.80). Chlorine: 1.63 ppm avg (0.40–2.30). Nitrate (Metro): 0.180 ppm (0.126–0.249). Nitrate (Smyrna): 1.77 ppm (10/09/24). Fluoride (Metro): 0.68 ppm (0.61–0.75). Fluoride (Smyrna): 0.492 ppm avg (0.453–0.580). Sodium (Metro): 9.97 ppm (7.80–11.3). Sodium (Smyrna): 11.00 ppm. Lead (2022): 90th% <2.00 ppb, 0/30 exceeded AL (range <2.00–3.19 ppb). Copper (2022): 90th% 0.104 ppm, 0/30 exceeded AL (0.00874–0.231 ppm). Turbidity: Metro 99.5%, Smyrna 100%, below 0.3 NTU. Total Coliform: 0 positives. Zero violations 2024.
Source: Percy Priest Lake (surface water). TDEC SWAP: reasonably susceptible. Lead Service Line Inventory complete: no lead found anywhere in distribution system. 68 additional sampling stations added in 2024 by City of La Vergne Public Works. Lead testing: 0/30 exceeded AL. Turbidity: 100% of samples below monthly limit. TTHMs and bromodichloromethane detected above EWG guidelines per EWG historical database. Contact: Danny Campbell at Inframark, 615-793-6536 option 2. Security: 615-793-7744. lavergnetn.gov/251.
Five Utilities Serving the Nolensville Area
Nolensville, College Grove, La Vergne, and the broader southern Williamson and Rutherford County area are served by five utilities. Which utility serves your specific address depends on your location — confirm by checking your water bill.
Nolensville-College Grove Utility District
La Vergne Water System
Why does Nolensville’s water have such high TTHMs?
NCGUD purchases treated water from Metro Nashville and the Town of Smyrna. Each source delivers water with some TTHMs already formed from chlorination. TTHMs then continue forming in NCGUD’s own distribution pipes as residual chlorine reacts with natural organic matter. By the time water reaches taps, cumulative TTHMs have built to 77.53 ppb average LRAA, with a quarterly high of 81.80 ppb exceeding the EPA 80 ppb limit. This is a chemistry and infrastructure challenge, not a compliance failure — but it makes carbon filtration the most urgent water quality action for Nolensville residents.
Contaminants Exceeding EWG Health Guidelines
All contaminants below are within EPA legal limits on an annual average basis. NCGUD 2024 CCR and La Vergne 2025 CCR are the most current verified data. Milcrofton UD and other figures are from EWG’s historical database.
(37.20–81.80 range)
Percy Priest Lake source
EWG historical data
Key Utilities — Side-by-Side Comparison
| Contaminant | EWG / EPA Limit | NCGUD 2024 CCR |
La Vergne WS 2025 CCR |
Milcrofton UD TN0000247 |
|---|---|---|---|---|
| TTHMs (LRAA) | 0.15 ppb / 80 ppb | 77.53 ppb (37.20–81.80) | Above EWG (EWG hist.) | Above EWG |
| HAA5 (LRAA) | 0.1 ppb / 60 ppb | 36.55 ppb (19.40–46.80) | Above EWG | Above EWG |
| Bromodichloromethane | 0.06 ppb | 8.12 ppb · 135x (EWG hist.) | Above EWG | Above EWG |
| PFOA / PFOS | 0.09 ppt / 4 ppt | Not in 2024 CCR | Not reported | Above EWG (EWG data) |
| Chromium-6 | 0.02 ppb | Not in CCR | Not reported | Above EWG |
| Nitrate (highest) | 0.14 ppm / 10 ppm | 1.77 ppm (Smyrna src) · 12.6x EWG | Not in CCR | Above EWG |
| Lead (most recent) | 0 / AL 15 ppb | <2.00 ppb 90th% · 0/30 (2022) | 0/30 exceeded AL (2025) | EWG data |
| Lead in distribution | — | Not specified | No lead found (LSLI complete 2025) | Not verified |
| Violations 2024/25 | — | Zero (2024) | Zero (2025) | Not verified |
| Above EWG / Total | — | 9 of 15 | 8+ (EWG data) | 9 of 14 |
Protecting Children & Pregnant Women in Nolensville
Nolensville is one of Tennessee’s fastest-growing communities — with abundant new construction and young families. NCGUD’s 77.53 ppb TTHMs are the highest of any utility in this guide series and a meaningful concern for pregnant women and young children.
Disinfection byproducts have been linked in studies to pregnancy complications including low birth weight, preterm birth, and neural tube defects. NCGUD’s 77.53 ppb LRAA (quarterly highs 81.80 ppb) is the highest of any utility in this guide series. The first trimester is the highest-risk window. A whole-house carbon filter plus under-sink RO provides the most complete protection for pregnant women in Nolensville.
NCGUD 2022: 0/30 exceeded lead AL (<2.00 ppb 90th%). La Vergne 2025: 0/30 exceeded AL and no lead found in the entire distribution system (complete Lead Service Line Inventory). Good system-level results. Lead can still come from home plumbing in pre-1986 homes. Flush cold tap 30 seconds before use in older homes. Use NSF/ANSI 53 certified filter for drinking.
No source utility approaches the EPA 10 ppm acute nitrate limit. The Smyrna source in NCGUD’s blend shows 1.77 ppm — 12.6x EWG’s guideline but well within the EPA limit. For infants under 6 months, use RO-filtered water for all formula preparation. Never boil tap water for infant formula — boiling concentrates nitrate.
PFOA is detected above EWG guidelines in Milcrofton UD (Williamson County). NCGUD’s 2024 CCR does not report PFAS. Studies link PFAS to immune suppression, thyroid disruption, and developmental effects in children. Reverse osmosis provides the most complete household PFAS treatment and the best future insurance if NCGUD’s own monitoring confirms future detection.
Your Pets & Nolensville Water Quality
NCGUD’s 77.53 ppb TTHMs — the highest in this guide — mean proportionally higher exposure for small pets relative to body weight. The same contaminants affect your animals at doses scaled to their smaller size.
A 15-pound dog drinking the same TTHM-level water as a 160-pound adult receives roughly 10x the relative exposure per pound of body weight. At 77.53 ppb average — the highest of any utility in this guide — long-term TTHM exposure has been associated with elevated bladder cancer risk in some dog breeds. Fill your pet’s bowl from your RO-filtered tap.
Rabbits, guinea pigs, hamsters, and birds have tiny body masses — their relative contaminant exposure is far higher. At NCGUD’s elevated TTHM levels, chronic lifetime exposure warrants care. RO-filtered water is strongly recommended for all small caged animals and birds.
Chlorine in NCGUD tap water (1.63 ppm avg) is directly toxic to fish and aquarium invertebrates. Never add untreated tap water to a tank. Activated carbon removes free chlorine. RO is the gold standard for sensitive species, reef tanks, and shrimp. Never boil tap water for aquarium use.
Dogs and cats: RO-filtered tap water for their bowl. Whole-house carbon is a meaningful improvement. Small animals and birds: RO or filtered water strongly recommended. Fish: Always dechlorinate tap water before adding to tanks. Use RO for sensitive species.
What Hard Water Is Doing to Your Nolensville Home Every Day
Williamson County sits on limestone geology. Surface water sources pick up calcium and magnesium that treatment does not remove. Nolensville’s rapid growth — lots of new construction with tankless water heaters — makes hard water scale a real and costly problem.
Calcium and magnesium ions disrupt the skin’s moisture barrier after showering — dryness, irritation, and increased eczema risk for children. Hard water mineral deposits coat hair, making it feel rough and dull. Color-treated hair fades faster. A softener or KDF showerhead filter addresses this directly.
White spots and cloudy film are calcium carbonate — limestone in liquid form. When hard Williamson County water evaporates in your dishwasher, minerals bond to glassware. Dishwasher detergent needs 50–75% more product in hard water. A softener eliminates spotting entirely.
Mineral deposits build up in fabric fibers — clothes feel stiff, whites yellow, colors fade, towels lose absorbency. Clothes washed in hard water wear out up to 15% faster. A softener restores detergent effectiveness and extends garment life significantly.
Scale reduces water heater efficiency 8% per GPG (U.S. Dept. of Energy). Williamson County limestone-derived hardness typically runs 7–9 GPG in the Hard zone. Nolensville’s abundant new construction with Navien and Rinnai tankless water heaters is especially sensitive — heat exchangers fail significantly faster on untreated hard water.
Williamson County Limestone Hard Water in Nolensville
Williamson County water is typically in the Hard zone, drawing from limestone-rich geology. Metro Nashville (one of NCGUD’s source utilities) confirms 5.88 GPG avg in its 2025 CCR. By the time water reaches Nolensville through additional distribution infrastructure, hardness is comparable. Private wells in Williamson County limestone aquifers can be significantly harder at 10–15+ GPG.
Nolensville Hard Water Impact Calculator
Williamson County Limestone Hard Water Impact Calculator
Default: 8 GPG — estimated typical Nolensville city water (Hard zone). Adjust to your specific test results.
Soft 3.5 GPG
Slightly Hard 7–10 GPG
Hard 10.5 GPG
Extremely Hard
Eco120°F
Standard130°F140°F
Tankless
PPM / mg/L
Grains per gallon
0–3Mod. Hard
3–5Hard
7–10Extremely Hard
10.5+
Nolensville, College Grove & Surrounding Area Guide
Which utility serves your address depends on your exact location in Williamson or Rutherford County. Check your water bill to confirm.
Find Your Area
Chlorine Residual in Nolensville Water
NCGUD and Milcrofton UD — the two utilities serving Nolensville — both use chlorine as their 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 Nolensville’s biggest water quality concerns.
Nolensville tap water runs at pool-level chlorine concentration
NCGUD’s chlorine residual is approximately 1.63 ppm at the tap. For comparison, the EPA-recommended range for a swimming pool is 1.0–3.0 ppm — meaning your Nolensville 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 Nolensville 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 1.63 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 Nolensville water it reacts with source water organic matter to produce TTHMs at 77.53 ppb (NCGUD) and PFOA above EWG guidelines (Milcrofton UD customers). 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 1.63 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.
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 Nolensville homes on NCGUD concerned about chlorine and TTHMs 77.53 ppb, or on Milcrofton UD concerned about PFOA above EWG, TTHMs, HAAs), a whole-house carbon system addresses both problems in one installation. See the filter recommendations below for Nolensville-specific sizing and pricing.
Filter Recommendations for Nolensville Homes
NCGUD’s 77.53 ppb TTHMs make whole-house carbon filtration the most urgent investment of any city in this guide. Williamson County hard water makes a softener important for appliance protection, especially in new construction with tankless heaters.
The Nolensville Water Treatment Recommendation
Get a personalized recommendation for your Nolensville address.
Connect with a vetted Williamson County water treatment professional.