Disinfection method data from 2025 CCRs. All verified utilities confirmed as free chlorine. Updated July 2025.
Section 1
Which disinfectant does your Middle Tennessee utility use?
The short answer: every verified utility in Middle Tennessee uses free chlorine, not chloramines. This is good news for filtration — free chlorine is significantly easier to remove than chloramines. However, chlorine levels vary dramatically across the region, from Gallatin CSB’s verified 1.09 ppm to Dickson WADC’s verified 2.56 ppm.
Middle Tennessee bottom line: All 17+ verified utilities in this guide use free chlorine as their primary disinfectant. A standard NSF/ANSI 42-certified activated carbon filter removes free chlorine completely at the point of use. You do not need catalytic carbon or a specialized chloramine filter in Middle Tennessee — but you do need carbon, because the chlorine levels here are high enough to form disinfection byproducts that matter.
| Utility / City | Disinfection method | Chlorine residual | Data source | Filter needed |
|---|---|---|---|---|
| Nashville MWS Davidson County | Free chlorine | 1.60 ppm | 2025 CCR verified | Activated carbon (NSF/ANSI 42) |
| NCGUD (Brentwood/Nolensville) Williamson County | Free chlorine | 1.63 ppm | 2025 CCR verified | Activated carbon (NSF/ANSI 42) |
| Franklin Water Dept. Williamson County | Free chlorine | ~1.70 ppm est. | Estimated | Activated carbon (NSF/ANSI 42) |
| Spring Hill / Milcrofton UD Williamson County | Free chlorine | ~1.65 ppm est. | Estimated | Carbon + RO (PFOA detected) |
| Dickson WADC Dickson County | Free chlorine | 2.56 ppm | 2025 CCR verified | Activated carbon (NSF/ANSI 42) — highest in guide |
| Columbia / Maury Co. Maury County | Free chlorine | ~1.82 ppm est. | Estimated | Activated carbon (NSF/ANSI 42) |
| Murfreesboro Water Rutherford County | Free chlorine | ~1.60 ppm est. | Estimated | Activated carbon (NSF/ANSI 42) |
| Smyrna Water System Rutherford County | Free chlorine | 1.53 ppm | 2025 CCR verified | Activated carbon (NSF/ANSI 42) |
| La Vergne Water Rutherford County | Free chlorine | ~1.53 ppm est. | Estimated | Activated carbon (NSF/ANSI 42) |
| Gallatin CSB Sumner County | Free chlorine | 1.09 ppm | 2025 CCR verified | Activated carbon (NSF/ANSI 42) |
| Hendersonville UD Sumner County | Free chlorine | ~1.58 ppm est. | Estimated | Activated carbon (NSF/ANSI 42) |
| Lebanon WWAWC Wilson County | Free chlorine | 1.34 ppm | 2025 CCR verified | Activated carbon (NSF/ANSI 42) |
| Mount Juliet WD Wilson County | Free chlorine | ~1.60 ppm est. | Estimated | Activated carbon (NSF/ANSI 42) |
| Springfield / Robertson Co. Robertson County | Free chlorine | ~1.58 ppm est. | Estimated | Activated carbon (NSF/ANSI 42) |
| Private Well Rural Middle Tennessee | No disinfection | N/A | N/A | Iron filter + UV + softener (well-specific) |
Section 2
Chlorine vs chloramines: what the difference actually means
Both are disinfectants added to municipal water to kill bacteria and pathogens. They behave very differently once they reach your tap — and they require different filters to remove.
Free chlorine — used in all Middle TN utilities
Chlorine (Cl²)
Reacts with organic matter to form TTHMs and HAAs — the primary health concern in Middle Tennessee water
Produces noticeable pool smell — especially in summer when residuals are boosted
Dissipates when left in open container overnight
Removed completely by standard activated carbon (NSF/ANSI 42)
Middle Tennessee range: 1.09 ppm (Gallatin) to 2.56 ppm (Dickson)
Chloramines — not used in Middle Tennessee
Chloramines (NH²Cl)
More stable than free chlorine — lasts longer in distribution systems, preferred by large urban utilities
Produces less TTHM formation but creates different byproducts (HANs, nitrosamines)
Does not dissipate from standing water
Requires catalytic carbon or ascorbic acid to remove — standard carbon is insufficient
Harsher on fish, reptiles, and dialysis patients than free chlorine
Why this matters for your filter purchase: Salespeople sometimes recommend catalytic carbon or specialty “chloramine filters” to Middle Tennessee homeowners. In any verified Middle Tennessee utility, this is unnecessary upselling — and adds $200–$600 to the system cost. Standard activated carbon (NSF/ANSI 42 certified) removes free chlorine completely. If a company tells you that you need catalytic carbon for Nashville, Franklin, Murfreesboro, or any other Middle Tennessee city water, ask them to show you the CCR that justifies it.
Section 3
Why Middle Tennessee’s chlorine levels matter even though they’re all free chlorine
The fact that Middle Tennessee uses free chlorine rather than chloramines is good news for filtration. But the chlorine levels themselves are significant — and vary enough across the region that the right system for a Dickson County home is not the same as the right system for a Gallatin home.
Dickson County
Free Chlorine
2.56 ppm verified — highest in guide. Whole-home carbon strongly recommended. TTHMs + PFOA above EWG.
Columbia / Maury Co.
Free Chlorine
~1.82 ppm est. — Duck River organic loading drives elevated TTHMs and HAAs. Carbon filter strongly recommended.
Franklin
Free Chlorine
~1.70 ppm est. — BrCHM 100x EWG, chlorate 2.8x EWG. Carbon + RO for comprehensive protection.
Brentwood / Nolensville
Free Chlorine
1.63 ppm verified — TTHMs 77.53 ppb, highest in guide. Carbon minimum, RO strongly recommended.
Nashville MWS
Free Chlorine
1.60 ppm verified — 7 above EWG guidelines. Standard whole-home or under-sink carbon addresses chlorine and TTHMs.
Spring Hill / Milcrofton
Free Chlorine
~1.65 ppm est. — PFOA above EWG. Carbon removes chlorine but RO required for PFAS removal.
Lebanon WWAWC
Free Chlorine
1.34 ppm verified — 8 contaminants above EWG. TTHMs 49 ppb. Carbon minimum.
Smyrna
Free Chlorine
1.53 ppm verified — BrCHM 108x EWG. Carbon + consider RO for byproducts.
Gallatin CSB
Free Chlorine
1.09 ppm verified — lowest in guide. Basic activated carbon is sufficient for chlorine removal.
Section 4
Which filter removes chlorine in Middle Tennessee
Since all Middle Tennessee utilities use free chlorine, the filter decision is straightforward — but the right size and configuration depends on your specific city’s chlorine level and contaminant profile.
Works for all Middle TN cities
Activated carbon (GAC)
NSF/ANSI 42 certified. Removes free chlorine completely at the point of use — whether whole-home or under-sink. Also reduces TTHMs and HAAs significantly. The baseline solution for every Middle Tennessee utility on this list.
Works — not required for chlorine alone
Catalytic carbon
Removes both free chlorine and chloramines. Not necessary for any Middle Tennessee utility (all use free chlorine) but does no harm if already installed. If a salesperson recommends this specifically for chloramine removal in Middle Tennessee, ask for the CCR that justifies it.
Works — required for Spring Hill / Milcrofton PFAS
Reverse osmosis (NSF/ANSI 58)
Removes chlorine, TTHMs, PFAS, lead, chromium-6, microplastics, and virtually everything else. Required for Spring Hill / Milcrofton UD customers where PFOA has been detected above EWG guidelines. Optional (but comprehensive) for all other Middle Tennessee cities.
Not sufficient alone for high-byproduct cities
Pitcher filter (basic)
NSF/ANSI 42 certified pitchers remove chlorine taste and odor at the point of use. Sufficient for drinking water in lower-chlorine cities like Gallatin. Not sufficient as a whole-home solution, and doesn’t help with shower chlorine or appliances.
Does not remove chlorine
Water softener (ion exchange)
Removes calcium and magnesium hardness through ion exchange but does not remove chlorine, TTHMs, or disinfection byproducts. In Middle Tennessee, a softener should be paired with a carbon filter — not used as a substitute for one.
Does not remove chlorine
Sediment filter
Removes particulate matter and turbidity only. Has no effect on dissolved chlorine, TTHMs, PFAS, or other chemical contaminants. Often sold as a pre-filter add-on — on treated Middle Tennessee municipal water, a sediment pre-filter is rarely necessary and typically an upsell.
Section 5
Health effects specific to Middle Tennessee chlorine levels
At the residual levels common across Middle Tennessee — 1.09 to 2.56 ppm — free chlorine affects daily life in ways that go beyond taste and smell.
Most significant concerns
Disinfection byproducts (TTHMs & HAAs)
Chlorine + organic matter = TTHMs and haloacetic acids. Long-term exposure linked to bladder cancer, liver effects, and reproductive concerns in multiple EPA studies.
Middle Tennessee rivers and lakes (Duck River, Cumberland River, Percy Priest Lake) have high natural organic content, driving elevated TTHM formation.
Dickson (2.56 ppm) and Brentwood/Nolensville (TTHMs 77.53 ppb) are the highest-concern utilities in the guide.
Removed by activated carbon and RO. Not removed by softeners or sediment filters.
Daily quality-of-life effects
Skin, hair, and household effects
Dry skin and irritated scalp — consistently reported by new Middle Tennessee residents, particularly those from states with softer or lower-chlorine water.
Pool smell in hot showers — chlorine off-gasses in steam. At Dickson’s 2.56 ppm, this is particularly noticeable.
Laundry fading — chlorine bleaches fabrics over time, particularly at higher residual levels.
Pets and plants — chlorine affects gut bacteria in pets and is absorbed by plant roots. Carbon-filtered water is preferable for both.
Frequently Asked Questions
Common questions
Nashville Metro Water Services uses free chlorine, verified in the 2025 CCR at 1.60 ppm average. Nashville does not use chloramines. A standard NSF/ANSI 42-certified activated carbon filter removes Nashville’s chlorine completely at the point of use.
No verified Middle Tennessee utility in this guide uses chloramines as their primary disinfectant. All 14 utilities with available 2025 CCR or estimated data use free chlorine. If you are outside of a listed utility’s service area, check your annual CCR (water bill or utility website) and look for “chloramine” or “combined chlorine” in the disinfection residual section.
No — catalytic carbon is designed to remove chloramines, which are not used by any verified Middle Tennessee utility. Standard activated carbon (NSF/ANSI 42 certified) removes free chlorine completely. If a salesperson recommends catalytic carbon for your Middle Tennessee municipal water, ask them to show you CCR documentation confirming your utility uses chloramines before agreeing to the upgrade. In almost all Middle Tennessee installs, it is unnecessary.
Free chlorine at Middle Tennessee’s typical residual levels (1.09–2.56 ppm) produces a noticeable chlorine odor — particularly in hot showers where the chlorine off-gasses in steam, and in summer when utilities boost residuals to maintain disinfection across longer distribution routes. An activated carbon whole-home filter eliminates the smell at every tap and shower.
For most residential purposes: it depends on context. Chloramines form fewer TTHMs than free chlorine but produce different byproducts (HANs, nitrosamines) that also have health implications. Chloramines are significantly harder on fish, reptiles, and dialysis patients — these groups require catalytic carbon or ascorbic acid neutralization. For Middle Tennessee residents, this is not a pressing concern since no local utility uses chloramines — but it is important to understand if you move to a utility that does.
Find the right filter for your specific city
Every Middle Tennessee city has a different chlorine level and contaminant profile. Find your city’s verified CCR data and specific filter recommendation.
See filter recommendations by city → Nashville water guide