Fluoride in Union City’s water: fluoridated since 1953, running below target
Union City is one of Tennessee’s longest-running fluoridation towns — and its current level sits noticeably under the national target. Here is the record, the number, and what the gap means for your family’s routine.
Union City has fluoridated its water since May 1953, according to the CDC’s Fluoridation Census — and its own 2025 water quality report measures fluoride at 0.42 mg/L (range 0.29–0.57). That is real fluoride in the water, but it is below the CDC’s recommended 0.7 mg/L.
Water quality in Union City
Curious about your tap water? Tennessee Water Authority has the full Union City water quality guide — contaminant data, utility details, and filter recommendations.
How to read this page: the fluoridation status rests on the CDC census record (adjusted fluoridation since 1953) plus the utility’s own measured levels — the 2025 report’s “water additive” line is standard wording printed in water reports everywhere, and we do not treat it by itself as proof of current adjustment. Every figure below is cited to its source at the bottom of the page.
Union City’s fluoride facts
The system, the source, the history, and the measured level — each from a named record.
- Utility
- Union City Water Department (printed as Union City Water System in its own reports)State system ID TN0000720 — the same ID in the Tennessee Water Authority guide, the CDC Fluoridation Census, and EPA’s SDWIS database.
- Source water
- Memphis Sand Aquifer groundwaterWells drawing from the same deep sand aquifer that supplies much of West Tennessee.
- People served
- About 16,180
- Fluoridated since
- May 1953 — adjusted fluoridation, sodium fluorosilicatePer the CDC Fluoridation Census. “Adjusted” means the utility adds fluoride to reach a target, as opposed to relying on whatever occurs naturally.
- Measured level
- 0.42 mg/L, range 0.29–0.57 (2025)From the Union City Water System Water Quality Report for 2025. The prior year ran the same pattern: 0.32 mg/L, range 0.25–0.46 (2024 report). Both years sit below the CDC’s 0.7 mg/L recommendation.
- Purchased-water areas
- Reelfoot Water Association buys Union City waterThe census lists Reelfoot as a consecutive (purchased-water) system under Union City, so Reelfoot customers receive Union City’s supply — and its fluoride situation follows Union City’s. We publish no separate Reelfoot figure.
A word on the debate, since it comes up in every Tennessee town: reasonable people disagree about whether governments should fluoridate water at all, and this page takes no side in that argument. What we can do is keep the numbers straight. Union City’s measured level is well under every federal safety limit — and also under the level public-health agencies consider optimal for cavity prevention. Both of those facts matter, and the practical advice below follows from the second one.
For the full picture — how fluoride works, the recent studies, and the arguments on both sides, with every claim cited — see our complete fluoride guide.
The level: 0.42 mg/L against the benchmarks
Three national numbers frame every fluoride conversation, and they are constantly confused with each other — a recommended target, a cosmetic-effects guideline, and a legal ceiling are three different things. Here they are, kept separate, with Union City’s verified level on top.
| Level | Value | What it means |
|---|---|---|
| Union City Water System — measured levelUnion City Water System Water Quality Report for 2025 | 0.42 mg/Lrange 0.29–0.57 | The utility’s own 2025 measurement. Below the CDC’s recommended level — some background protection, less than the intended dose. |
| CDC recommended levelU.S. Public Health Service / CDC, since 2015 | 0.7 mg/L | The target for water systems that choose to fluoridate — judged to prevent cavities while keeping fluorosis risk low. A recommendation, not a law. |
| EPA secondary standard (SMCL)EPA, not federally enforceable | 2.0 mg/L | A guideline aimed at preventing tooth discoloration. Systems above it must notify the public; it is a cosmetic-effects standard, not a health-based limit. |
| EPA maximum contaminant level (MCL)EPA, enforceable | 4.0 mg/L | The legal ceiling for fluoride in public drinking water, set to protect against bone and severe tooth damage. Applies whether fluoride is added or naturally occurring. |
mg/L and ppm are the same number for water. Read it plainly: Union City’s 0.42 mg/L is about 60% of the CDC’s recommended target, roughly one-fifth of the EPA’s secondary guideline, and about one-tenth of the legal maximum. The full report is the utility’s Water Quality Report for 2025 (PDF).
Do you still need fluoride toothpaste? Yes — here’s why
Fluoridated water is one layer of protection: a steady, low-dose background exposure every time you drink. It was never the whole routine, and in Union City — where the tap runs at 0.42 instead of 0.7 — the other layers carry more weight than they would in a town at target.
01 Toothpaste is the main event
Water fluoride works in the background; brushing twice a day with fluoride toothpaste delivers the concentrated dose that does the heavy lifting, right on the enamel. The two exposures are designed to work together. Living in a fluoridated city is not a reason to switch to fluoride-free toothpaste — and in a below-target city like Union City, giving up toothpaste fluoride means giving up the stronger half of your protection.
02 Kids’ amounts still matter
Per the ADA and the American Academy of Pediatric Dentistry: a smear the size of a grain of rice from the first tooth until age 3, then a pea-size amount from age 3 on. Teach kids to spit, don’t swallow, and supervise while they’re young. The small amounts are deliberate — enough to protect forming teeth without overdoing the total.
03 Varnish helps close the gap
Fluoride varnish — the concentrated coating painted on at a cleaning — is worth a real conversation at every checkup in Union City, because it helps make up the difference between 0.42 mg/L and the 0.7 target. That goes double for children and for higher-risk adults: people with frequent cavities, dry mouth, braces, or gum recession exposing softer root surfaces. If it’s offered, ask what risk it’s treating — here, the answer is usually a straightforward one.
04 Supplements: ask first
Fluoride tablets and drops exist for children whose water provides too little, and a below-target supply is exactly the situation where a dentist or pediatrician might consider them. They are also dose-sensitive: too much while teeth are forming risks fluorosis, too little does nothing. Never self-prescribe them. Bring your water situation up at your child’s next checkup and let a professional weigh age, diet, and toothpaste use.
The Union City routine, in one place
- Brush twice a day with fluoride toothpaste — rice-grain smear under 3, pea-size from 3 on.
- Spit, don’t swallow; rinse lightly or not at all after brushing.
- Ask about fluoride varnish at cleanings — for kids, and for adults with cavities, dry mouth, braces, or recession.
- Supplements only if a dentist or doctor recommends them for your child.
On a private well? Test first
Well water is a separate question entirely
Private wells around Obion County draw on the same Memphis Sand Aquifer, but no utility fluoridates, tests, or reports on them — that’s on you. The natural fluoride level in well water varies: some wells have very little, some sit near the recommended level, and a few naturally run high. That cuts in both directions.
Have your water tested by a certified laboratory first (your county health department can point you to one). Then take the result to your child’s dentist or pediatrician before starting any supplement. Testing is also the only way to catch the opposite problem — a natural level high enough to risk fluorosis in young kids.
How to confirm Union City’s level yourself
Don’t take any website’s word for it — including ours. Three direct routes:
- Read the utility’s own 2025 report. The Union City Water System Water Quality Report for 2025 is posted on the city’s website and lists fluoride at 0.42 mg/L, range 0.29–0.57. It is the utility’s own current statement of what is in the water it delivers.
- Check the CDC’s My Water’s Fluoride. The CDC’s database at nccd.cdc.gov/DOH_MWF lets you look up your water system and its fluoridation status from state-reported data. States report voluntarily and the data is not real-time, so if it ever disagrees with a current water quality report, trust the report.
- Call the utility. The contact named in the Union City report itself is Jason Moss, (731) 885-9622 — the person the utility lists for questions about its water.
Questions Union City families actually ask
Yes, by the record we can verify. The CDC’s Fluoridation Census lists Union City as an adjusted (fluoridated) system since May 1953, using sodium fluorosilicate. The utility’s own 2025 water quality report measures fluoride at 0.42 mg/L (range 0.29–0.57), which fits a fluoridating system — though the level is below the CDC’s recommended 0.7 mg/L. One honesty note: the report’s fluoride line uses standard wording and does not by itself prove the utility is still adjusting today; the status rests on the census record plus the measured levels.
It helps, but it is below the level the CDC considers optimal. The CDC recommends 0.7 mg/L for systems that fluoridate; Union City measured 0.42 mg/L in 2025 and 0.32 mg/L in 2024. You are getting some background protection from the tap — just not the full intended dose — which makes fluoride toothpaste and, for higher-risk kids and adults, in-office varnish more important here than in a town sitting right at 0.7.
Yes. Fluoridated water is background exposure — a low level touching your teeth throughout the day. Toothpaste is the main event: a concentrated dose, twice a day, right on the enamel. The two are designed to work together, and that is doubly true in Union City, where the water level runs below the recommended target. Switching to fluoride-free toothpaste because “the water has it covered” gives up the stronger of the two protections.
Per the ADA and the American Academy of Pediatric Dentistry: a smear the size of a grain of rice from the first tooth until age 3, then a pea-size amount from age 3 on. Brush twice a day, teach kids to spit rather than swallow, and supervise brushing while they are young. The small amounts are deliberate — enough to protect forming teeth without overdoing the total while children are still swallowing some of it.
It is well worth asking about in Union City. Varnish is a concentrated fluoride coating painted on at a checkup, and it matters more where the water runs below target — it helps close the gap between 0.42 mg/L and the recommended 0.7. The U.S. Preventive Services Task Force recommends varnish for all children from the first tooth through age 5, and dentists often extend it to older kids and adults at higher cavity risk — frequent cavities, dry mouth, braces, or exposed roots from gum recession.
Read the utility’s own report: the Union City Water System Water Quality Report for 2025 is posted on the city’s website (unioncitytn.gov) and lists fluoride at 0.42 mg/L with a range of 0.29–0.57. You can also look the system up in the CDC’s My Water’s Fluoride database at nccd.cdc.gov/DOH_MWF. Still unsure? The contact named in the utility’s own report is Jason Moss, (731) 885-9622.
Sources & method
- Union City Water System Water Quality Report for 2025 — fluoride level found 0.42 ppm (mg/L), range of detections 0.29–0.57, sampled 2025; source water identified as Memphis Sand Aquifer groundwater; utility contact Jason Moss, (731) 885-9622. unioncitytn.gov (PDF). Its chlorine figure (1.74 ppm) matches the Tennessee Water Authority guide exactly, confirming this is the report behind the guide.
- Union City Water System Water Quality Report for 2024 — prior year: fluoride 0.32 ppm, range 0.25–0.46, unioncitytn.gov (PDF).
- CDC Fluoridation Census — Union City (system 0000720) listed as adjusted fluoridation (ADJ) using sodium fluorosilicate (NaSiF6), start date May 1953; Reelfoot Water Association (0000757) listed as a consecutive (purchased-water) system under Union City.
- CDC — community water fluoridation recommendation of 0.7 mg/L; My Water’s Fluoride lookup for system-level fluoridation status.
- U.S. EPA — fluoride maximum contaminant level (MCL) of 4.0 mg/L (enforceable) and secondary standard (SMCL) of 2.0 mg/L (guideline for tooth discoloration). System identity TN0000720 corroborated in EPA’s SDWIS database.
- American Dental Association & American Academy of Pediatric Dentistry — children’s fluoride toothpaste amounts: rice-grain smear to age 3, pea-size from age 3, twice daily.
- U.S. Preventive Services Task Force (2021) — B recommendation: fluoride varnish for all children from first-tooth eruption through age 5; oral fluoride supplementation from 6 months when the water supply is deficient in fluoride.
- Utility identification — Union City Water Department / Union City Water System, system ID TN0000720, Memphis Sand Aquifer groundwater, serving about 16,180 people.
Method in one line: Union City’s level comes from the utility’s own 2025 water quality report; its fluoridation history comes from the CDC Fluoridation Census; national benchmarks are cited to the CDC and EPA and are never presented as Union City measurements. The report’s generic “water additive” wording is not treated, by itself, as proof of current adjustment — this page says so openly rather than overstating the record.