Fluoride in Brentwood, TN
Four utilities serve Brentwood addresses, and they do not all deliver the same water. The Metro share runs at the CDC target; the Harpeth Valley water behind Mallory Valley — and much of the Nolensville-College Grove blend — runs below it.
Brentwood’s water is fluoridated — at three verified levels. Nashville Metro water runs 0.67 mg/L, essentially at the CDC 0.7 mg/L target. Mallory Valley and much Nolensville-College Grove water runs 0.53 mg/L, below the CDC recommended level, and Smyrna-sourced water averaged 0.492 mg/L. All are far below EPA limits.
How this page works: the levels below come from the treating utilities’ own published water quality reports, presented per utility and per source — not from a marketing claim or a guess. Where a figure could not be verified (Gateway Utility), this page says so instead of filling the gap. New to the topic? Start with our full fluoride guide.
Water quality in Brentwood
Curious about your tap water? Tennessee Water Authority has the full Brentwood water quality guide — contaminant data, utility details, and filter recommendations.
Brentwood’s fluoride, by utility
Everything on this page traces back to these facts, from each utility’s own published water quality report.
LEVEL Metro Water Services (N. Brentwood)
0.67 mg/L
Range 0.56–0.75 mg/L, 2025 Water Quality Report. Essentially at the CDC 0.7 mg/L target.
LEVEL Mallory Valley UD (central Brentwood)
0.53 mg/L average
Range 0.25–0.65 mg/L. Mallory Valley purchases Harpeth Valley UD–treated water; the figure is HVUD‘s treated level, reported in NCGUD‘s 2025 report. Below the CDC recommended 0.7 mg/L — stated plainly.
LEVEL Nolensville-College Grove UD, by source
0.492–0.67 mg/L
The district blends three purchased sources and reports each one: Metro 0.67 mg/L and Mallory Valley water 0.53 mg/L avg (2025 report); Smyrna water 0.492 mg/L avg (2024 report). Two of the three sources run below the CDC target.
STATUS Fluoridated — adjusted
Every treating system adds fluoride. The CCR source language is “Water additive which promotes strong teeth.” Gateway Utility (1,070 served, south Williamson County) is the exception on this page: no fluoride figure could be verified for it, so we publish none.
UTILITY Four utilities serve Brentwood
Metro Water Services (TN0000494, ~755,890 served) · Mallory Valley UD (TN0000428, ~27,656) · Nolensville-College Grove UD (TN0000511, ~32,335) · Gateway Utility (TN0008271, ~1,070).
SOURCE Cumberland River, via suppliers
Metro treats Cumberland River water at its own plants. Mallory Valley buys Harpeth Valley UD water (also Cumberland River). NCGUD buys from Metro, Smyrna, and Mallory Valley.
How Brentwood’s levels compare
Brentwood has three verified levels, not one — so the table carries all three, next to the benchmarks that matter, each labeled for exactly what it is.
| Benchmark | Level | How this compares |
|---|---|---|
| Metro Water Services, 2025 | 0.67 mg/L | Range 0.56–0.75 mg/L. Essentially at the CDC target. |
| Mallory Valley UD (HVUD water), 2025 | 0.53 mg/L avg | Range 0.25–0.65 mg/L. Below the CDC recommended level — we won’t round it up to the target. |
| NCGUD — Smyrna source water, 2024 | 0.492 mg/L avg | The lowest of NCGUD’s three sources — about seven-tenths of the CDC target. |
| CDC recommended level | 0.7 mg/L | The level the CDC recommends community systems target. |
| EPA secondary (non-enforceable) standard | 2.0 mg/L | A guideline aimed at preventing cosmetic effects like tooth discoloration. |
| EPA enforceable maximum contaminant level (MCL) | 4.0 mg/L | The legal limit — a safety ceiling, not a target. |
Gateway Utility, the smallest Brentwood-area system (1,070 served), has no row in this table: no fluoride figure for it could be verified from a published report, so this page publishes none rather than borrow a neighbor’s number.
Brentwood is not one water system
Which level is yours depends on your utility: Metro Water Services in northern Brentwood (0.67 mg/L), Mallory Valley UD in central Brentwood (0.53 mg/L average), Nolensville-College Grove UD to the southeast (a blend of 0.492–0.67 mg/L sources), or Gateway Utility in south Williamson County (unverified). Check your water bill for your utility’s name before assuming any number on this page is your number.
Do you still need fluoride toothpaste?
Yes — and this is the point people most often get backwards.
Fluoridated drinking water is background exposure. Every glass of water bathes your teeth in a low level of fluoride, and that steady, low-level contact genuinely helps enamel resist acid. But it is a base layer, not the main event. Fluoride toothpaste delivers a much more concentrated dose directly onto the enamel, twice a day, right where decay starts.
That holds on every Brentwood system — at Metro’s 0.67 mg/L and at Mallory Valley’s below-target 0.53 mg/L alike: brush twice daily with fluoride toothpaste. If you have been skipping fluoride toothpaste because “it’s in the water anyway,” the water was never carrying that load on its own.
Fluoride and kids: the amounts matter
Young children swallow toothpaste, so the ADA's guidance is about using the right small amount — not about avoiding fluoride toothpaste.
UNDER 3 A rice-grain smear
For children under age 3, use a smear of fluoride toothpaste about the size of a grain of rice. That tiny amount is deliberate — it protects the teeth while keeping what gets swallowed to a minimum.
AGES 3+ A pea-size amount
From age 3 up, a pea-size amount is enough. A ribbon of paste running the length of the brush is several times more than a child needs.
- Supervise brushing. An adult should be watching (and helping) until a child can reliably spit and rinse on their own.
- Teach spitting, not swallowing. Spit the toothpaste out when done; swallowing it as a habit is what the small amounts are designed to guard against.
- Don’t load the brush. More paste does not mean cleaner teeth — it mostly means more swallowed.
What about fluoride varnish at the dentist?
An in-office fluoride treatment or varnish is a much stronger, targeted dose than anything in tap water or toothpaste.
At Mallory Valley’s 0.53 mg/L average — and on the below-target shares of the Nolensville-College Grove blend — varnish remains worthwhile for kids and for adults at higher cavity risk: people with recent cavities, dry mouth, braces, or exposed tooth roots. The water gives you a partial base layer, and varnish tops it up exactly where a clinician can see it’s needed.
If your cavity risk is low, it’s also reasonable to ask your dentist to walk you through your risk before a treatment — in either direction, the decision should be explained, not automatic.
On a private well? None of this applies automatically
Well water is not fluoridated by any utility
Nobody adjusts the fluoride in a private well — or tests it, unless you do. Well water may carry naturally occurring fluoride, almost none, or more than you'd expect, and taste won't tell you. If your home is on a well in Williamson County, have the water tested before assuming anything about its fluoride level, and tell your dentist you're on well water so your fluoride plan is built on your actual water, not the city's.
How to confirm Brentwood’s level yourself
Don’t take our word for it — the primary sources are public.
- Read your own utility’s current water quality report. The Nolensville-College Grove UD Water Quality Report for 2025 (PDF) lists fluoride for each of its purchased sources — Metro 0.67 mg/L, Mallory Valley water 0.53 mg/L average. Metro Water Services publishes its own annual report for its direct customers.
- Check CDC’s My Water’s Fluoride. The CDC’s system-by-system tracker at nccd.cdc.gov/DOH_MWF lists fluoridation status and levels for community water systems, including Metro (TN0000494), Mallory Valley (TN0000428), and NCGUD (TN0000511).
- Check whose name is on your bill. If your bill names a purchasing district, its supplier’s report governs your tap — Mallory Valley’s water is Harpeth Valley water, and NCGUD’s is a blend of its three sources.
For the bigger picture — how fluoridation works, the arguments on both sides, and how to think about filters — see our full fluoride guide.
Questions people actually ask
Asked the way people actually ask them — answered from the sources cited below.
Yes — on every Brentwood system with verified data. Nashville Metro Water Services reported 0.67 mg/L in its 2025 water quality report. Mallory Valley Utility District delivers Harpeth Valley–treated water averaging 0.53 mg/L. Nolensville-College Grove UD blends three purchased sources — Metro at 0.67 mg/L, Mallory Valley water at 0.53 mg/L, and Smyrna water at 0.492 mg/L (2024 report). For Gateway Utility, the smallest of the four systems, we could not verify a fluoride figure.
It depends on your utility. Metro Water Services customers get about 0.67 mg/L, essentially at the CDC recommended 0.7 mg/L. Mallory Valley customers get an average of 0.53 mg/L (range 0.25–0.65). Nolensville-College Grove customers get a blend of its three sources, which ranged from 0.492 to 0.67 mg/L in the district's reports. Check your water bill for your utility's name — that utility's report governs your tap.
It is below the CDC recommended level of 0.7 mg/L — about three-quarters of it — and this page states that plainly rather than rounding it up. It is still far below both EPA standards: the secondary (non-enforceable) standard is 2.0 mg/L and the enforceable maximum contaminant level (MCL) is 4.0 mg/L. Brushing twice daily with fluoride toothpaste covers the rest of what your teeth need.
Work from the name on your bill. Mallory Valley Utility District serves much of central Brentwood and delivers water averaging 0.53 mg/L. Nolensville-College Grove UD serves the Nolensville corridor southeast of Brentwood and blends Metro (0.67 mg/L), Mallory Valley (0.53 mg/L), and Smyrna (0.492 mg/L) water. Gateway Utility serves a small part of south Williamson County; we could not verify its fluoride figure, so ask the utility directly.
Yes. Fluoridated drinking water is background exposure — it bathes your teeth in a low level of fluoride through the day, which helps, but it does not replace the concentrated fluoride that toothpaste delivers directly to the enamel while you brush. Brush twice a day with fluoride toothpaste, and treat the water as a helpful base layer, not the whole defense.
The ADA's guidance: for children under age 3, use a smear of fluoride toothpaste about the size of a grain of rice. For ages 3 and up, a pea-size amount is enough. Supervise brushing, teach your child to spit the toothpaste out rather than swallow it, and remember that more paste on the brush does not mean cleaner teeth — the small amounts are deliberate, because young kids swallow some no matter what.
For many people, yes — especially if your water comes from Mallory Valley or a below-target Nolensville-College Grove source at about 0.53 mg/L or less. An in-office fluoride treatment or varnish puts a much stronger dose directly on the teeth, and it remains worthwhile for kids and for adults at higher cavity risk — people with recent cavities, dry mouth, braces, or exposed roots. If your cavity risk is low, ask your dentist to explain your risk either way rather than accepting or skipping it on autopilot.
No utility fluoridates private well water — nobody adjusts it at all. Well water can contain some naturally occurring fluoride, a lot, or almost none, and you cannot tell by taste. If your home is on a well in Williamson County, have the water tested before assuming anything about its fluoride level, and tell your dentist you are on well water so your fluoride plan reflects it.
Start with your own utility's current water quality report — Metro Water Services' 2025 report and the Nolensville-College Grove UD 2025 report are linked in the sources below, and each lists fluoride by source with its level and range. You can also check CDC's My Water's Fluoride, which tracks fluoridation status and levels by water system. If your bill names a purchasing district, its supplier's report is the one that governs your tap.
Sources & method
- Metro Water Services, Water Quality Report 2025 — fluoride 0.67 mg/L, range 0.56–0.75 mg/L; system TN0000494 (as also reported in NCGUD’s 2025 report, below).
- Nolensville-College Grove Utility District, Water Quality Report for 2025 — fluoride (Metro) 0.67 mg/L (0.56–0.75); fluoride (MVUD) 0.53 mg/L avg (0.25–0.65); source language “water additive which promotes strong teeth”; ncgud.com/wp-content/uploads/2026/04/CCR-2025.pdf.
- Nolensville-College Grove UD, 2024 CCR (via the Tennessee Water Authority Brentwood guide’s verified-CCR transcription) — fluoride by source: Metro 0.68 ppm, Smyrna 0.492 ppm avg, Mallory Valley 0.56 ppm.
- Tennessee Water Authority, Brentwood water quality guide — four-utility structure, PWSIDs, and populations; tennesseewaterauthority.com/brentwood-tn-water-quality-guide.
- CDC — recommended fluoride level of 0.7 mg/L for community water systems; fluoridation status and levels are also tracked in CDC’s My Water’s Fluoride.
- EPA — enforceable maximum contaminant level (MCL) of 4.0 mg/L and secondary (non-enforceable) standard of 2.0 mg/L for fluoride in drinking water.
- American Dental Association (ADA) — children’s toothpaste amounts: a rice-grain smear under age 3, a pea-size amount at ages 3 and up, with supervised brushing.
Method in one line: Brentwood’s levels come from the treating utilities’ own published reports — Metro’s and NCGUD’s — presented per utility and per purchased source. Gateway Utility’s figure could not be verified, so none is published. We never name, rank, or recommend private dental practices.