One rule before you choose a filter: test your water first. Every media type in this guide targets specific contaminants. Buying a filter before knowing your water chemistry is like taking a prescription without a diagnosis. The right media match for a Nashville MWS customer (Cumberland River, 1.60 ppm chlorine avg, 5.88 GPG) is different from what a Leiper’s Fork well owner needs (iron, acidic pH, limestone hardness). Your city guide or a certified water test tells you which options below actually apply to your situation.

The Complete Filter & Media Guide

Search for a media type or filter by your primary concern. Click any card to expand the full specification, what it removes, what it misses, and how it fits Middle Tennessee water chemistry.

Removes / reduces
Chlorine, chloramines (partial), TTHMs, HAAs, VOCs, pesticides, herbicides (atrazine, 2,4-D), taste and odor compounds, some PFAS (with PFAS-specific media)
Does NOT remove
Hardness (Ca/Mg), iron, manganese, nitrate, heavy metals (lead, mercury, chromium-6), bacteria, fluoride, dissolved solids, TDS
3–7 yrs
Media lifespan
Backwashing
Maintenance
Adsorption
How it works
Middle Tennessee use: The workhorse for all surface water utility customers. Nashville MWS (1.60 ppm chlorine avg), Franklin WD (bromodichloromethane 100x EWG), Nolensville NCGUD (TTHMs 77.53 ppb LRAA) — a whole-house GAC backwashing tank is the foundation of any treatment system for Cumberland River, Harpeth River, or Duck River water.
ChlorineTTHMsHAAsVOCsIronNitrateChromium-6
Removes / reduces
Chlorine AND chloramines (much more effective than standard GAC), hydrogen sulfide (rotten egg), iron, some manganese, TTHMs, HAAs, VOCs, pesticides, taste and odor
Does NOT remove
Hardness, nitrate, fluoride, TDS, bacteria, heavy metals (chromium-6, lead), PFAS on its own (requires PFAS-specific media)
3–6 yrs
Media lifespan
Backwashing
Maintenance
Adsorption + Catalysis
How it works
Middle Tennessee use: The upgrade from standard GAC for any utility using chloramine rather than free chlorine for secondary disinfection. Nashville MWS uses chloramine in parts of the system. Catalytic carbon is also the preferred media for well water with both iron and hydrogen sulfide — a common combination in Dickson and Williamson County wells.
ChlorineChloraminesH&sub2;STTHMsHardnessNitrate
Removes / reduces
Up to 95–99% TDS, PFAS (with proper certification), nitrate, chromium-6, arsenic, fluoride, lead, barium, radium, strontium, TTHMs, HAAs, chlorine, nanoplastics, bacteria, viruses, most dissolved contaminants
Does NOT remove
Hydrogen sulfide, chlorine/chloramines (requires pre-filter to protect membrane), dissolved gases. Produces wastewater (3–5 gallons wasted per gallon produced for standard systems)
2–5 yrs
Membrane life
6–12 mo
Pre/post filter replacement
$600–$2,000
Installed cost
Middle Tennessee use: The most comprehensive point-of-use solution available. Essential for Spring Hill WD and Milcrofton UD customers with PFOA above EWG, any customer wanting nitrate removal, and the best bottled water replacement for all utilities. Nashville MWS customers: zero PFAS detected (2024 CCR) — RO is still valuable for chromium-6, TTHMs, and nanoplastic removal.
PFASNitrateChromium-6ArsenicNanoplasticsH&sub2;S (pre-treat first)
Removes / reduces
Calcium and magnesium (hardness) to near zero. Also reduces barium, radium, some iron (below 1 ppm), strontium, and certain heavy metals. Delivers measurably soft water: improved soap lather, softer skin and hair, scale-free fixtures.
Does NOT remove
Chlorine, TTHMs, HAAs, PFAS, nitrate, bacteria, iron above 1 ppm, sediment. Fouled by iron — must have iron filter before softener if iron exceeds 1 ppm (critical for well water).
5–10+ yrs
Resin lifespan
Salt regeneration
Maintenance
$2,500–$4,500
Installed cost
Middle Tennessee use: Hardness varies enormously — Nashville MWS 5.88 GPG (moderate), La Vergne estimated 10–12 GPG, Smyrna/Murfreesboro estimated 10–14 GPG, Williamson County rural wells 15–20+ GPG. A properly sized softener is the single most impactful quality-of-life investment for any household above 7 GPG. Size by actual GPG test — never by neighbor’s results.
Well water critical rule: Iron above 1 ppm fouls resin permanently. Always install an AIO iron filter BEFORE the softener. Never use a softener as your iron filter.
HardnessBariumRadiumIron (below 1 ppm only)TTHMsPFASNitrate
Removes / reduces
Chlorine, hydrogen sulfide, iron, lead, mercury, and some heavy metals via redox reactions. Inhibits growth of bacteria, algae, and fungi in filter housings — extends carbon media life when combined.
Does NOT remove
Hardness, nitrate, PFAS, organic chemicals (VOCs, pesticides), chromium-6, TTHMs/HAAs on its own. Not a standalone solution. Always used in combination with activated or catalytic carbon.
3–7 yrs
Media lifespan
Periodic backwash
Maintenance
Redox reaction
How it works
Middle Tennessee use: Commonly blended with carbon in whole-house filter tanks. Useful for well water with both chlorine (if shock-treated) and low-level iron. The bacteria-inhibiting property is valuable in filter tanks that can otherwise grow biofilm in humid Middle Tennessee conditions. Not a standalone treatment for iron at typical well water levels.
ChlorineH&sub2;SLead (partial)MercuryHardnessNitratePFAS
What it does
Converts dissolved calcium and magnesium into microscopic aragonite crystals that stay suspended in water and are less likely to adhere to pipe surfaces. Reduces scale formation in pipes and water heaters. No salt, no chemicals, no wastewater.
What it does NOT do
Does NOT remove calcium or magnesium from the water. GPG hardness reading is unchanged after treatment. Does not improve soap lathering, skin softness, hair texture, or laundry. Does not protect appliances from hardness-related damage the way a softener does.
3–5 yrs
Media lifespan
None required
Maintenance
No salt/chemicals
Operating cost
Middle Tennessee guidance: At 5–7 GPG (Nashville, Clarksville), SP3 can be a reasonable scale management supplement. At 10+ GPG (Murfreesboro, Smyrna, La Vergne, Williamson County wells), SP3 is not an adequate substitute for a properly sized salt-based softener. Always ask a vendor: “After installation, will my water test at a lower GPG reading?” The answer for SP3 is no.
SP3 is a scale conditioner, not a water softener. If a sales representative describes it as equivalent to a softener, that claim is inaccurate above moderate hardness levels.
Scale reduction (partial)Hardness removalSkin/hair benefitSoap lathering
Removes / reduces
Dissolved ferrous iron (clear-water iron) up to 10–15+ ppm by oxidizing it into solid ferric iron and filtering it out. Also reduces hydrogen sulfide (rotten egg smell) and manganese. Chemical-free oxidation via air injection.
Does NOT remove
Hardness, nitrate, bacteria, PFAS, organic chemicals. Cannot handle high sediment loads without pre-sediment filter. Requires pH above 6.8 — acidic water (common in Dickson County) requires acid neutralizer first.
5–8+ yrs
Media lifespan
Periodic backwash
Maintenance
No chemicals
Operating method
Middle Tennessee use: The essential first step for any well with iron above 1 ppm before water reaches the softener. Common across Williamson, Maury, Dickson, Robertson, and Cheatham County wells. Orange staining on toilets, laundry, and fixtures is the primary indicator. Must confirm pH is above 6.8 before installing — test first.
Ferrous ironH&sub2;SManganese (partial)HardnessBacteriaNitrate
Removes / reduces
Hydrogen sulfide (rotten egg odor/taste) as the primary target. Also reduces some iron and manganese. Air injection oxidizes dissolved H&sub2;S into elemental sulfur particles, which are then filtered by catalytic carbon or manganese dioxide media.
Does NOT remove
High iron without additional media, hardness, nitrate, bacteria, PFAS. If both high iron and sulfur are present, an AIO iron filter addressing both simultaneously is typically the better system choice.
4–7 yrs
Media lifespan
Periodic backwash
Maintenance
No chemicals
Operating method
Middle Tennessee use: The rotten egg smell is unmistakable in deeper wells across Williamson, Montgomery, and Dickson Counties. A dedicated sulfur filter or an AIO system with catalytic carbon media addresses both sulfur and iron when both are present. Test water to confirm H&sub2;S vs. sulfate-reducing bacteria — treatment differs.
H&sub2;S (rotten egg)Iron (partial)Manganese (partial)HardnessBacteria
What it does
Raises pH from acidic levels (often 5.5–6.5) to a neutral range (7.0–8.0) by slowly dissolving calcite (calcium carbonate) and/or corosex (magnesium oxide) media. Protects copper plumbing, water heaters, and other equipment from corrosion and pitting.
Does NOT remove
Does not remove contaminants. Adds a small amount of hardness minerals to the water as media dissolves. Does not address iron, bacteria, nitrate, or any chemical contaminant. Requires media replenishment once or twice per year.
Annual media top-up
Maintenance
No electricity
Operation
pH 5.5→7.0+
Typical correction
Middle Tennessee use: Critical pre-treatment step for Dickson County and Cheatham County well owners with acidic groundwater (pH below 6.5). Without correcting pH first, iron filters (Birm, AIO) cannot oxidize iron effectively — the most expensive mistake in well water treatment sequencing. Always test pH before purchasing any iron filter.
Raises pHStops pipe corrosionIron removalBacteriaContaminants
Removes / reduces
Kills bacteria (E. coli, coliform), viruses, and cysts (Cryptosporidium, Giardia) by damaging their DNA with UV-C light at 254 nm. Chemical-free. Does not change water chemistry or produce wastewater. Requires clear water — turbidity or iron shielding microorganisms from UV dose must be pre-treated.
Does NOT remove
Chemical contaminants of any kind: TTHMs, HAAs, PFAS, nitrate, hardness, iron, arsenic, chromium-6, lead, sediment. UV is a disinfection-only stage. Must come after all filtration to work correctly.
Annual lamp replacement
Critical maintenance
Quarterly
Quartz sleeve cleaning
Always last stage
Sequence position
Middle Tennessee use: Required for every private well in the region. Annual testing confirms no bacteria, but UV provides continuous protection between tests. Lamp must be replaced every 12 months even if still glowing — UV intensity drops below the required germicidal dose while the lamp still appears functional. The quartz sleeve must be cleaned quarterly to remove limestone scale — critical in high-hardness Middle Tennessee wells.
BacteriaE. coliVirusesCystsChemicalsIronHardness
Removes / reduces
Moderate iron and manganese by catalyzing oxidation of dissolved ferrous iron using dissolved oxygen naturally present in the water. Low-cost, chemical-free operation. No regenerant chemicals required.
Does NOT remove
High iron levels (above 5–8 ppm), sulfur, hardness, nitrate, bacteria. Requires pH above 6.8 and adequate dissolved oxygen in the water — not suitable for acidic well water without pH correction first.
4–6 yrs
Media lifespan
pH > 6.8 required
Water chemistry need
Periodic backwash
Maintenance
Middle Tennessee use: A cost-effective option for moderate-iron wells (under 5 ppm) with neutral to alkaline pH — common in Wilson County and parts of Williamson County. Not suitable for Dickson or Cheatham County acidic wells without pH correction first. For higher iron or combined iron-and-sulfur wells, Greensand Plus or an AIO system is more appropriate.
Iron (moderate)ManganeseHigh ironSulfurBacteria
Removes / reduces
Higher levels of iron, manganese, and hydrogen sulfide than Birm. More powerful oxidation via manganese dioxide coating. Handles a wider range of water conditions including lower dissolved oxygen and higher contaminant concentrations.
Does NOT remove
Hardness, nitrate, bacteria, organic chemicals. Requires chemical regeneration (potassium permanganate or chlorine) in most setups, adding to operating cost and maintenance. More complex than Birm.
5–8 yrs
Media lifespan
KMnO4 or Cl2 regen
Regenerant required
Periodic backwash
Maintenance
Middle Tennessee use: The step up from Birm for wells with higher iron concentrations (5–10+ ppm) or combined iron-manganese-sulfur problems. More common in deeper Rutherford County and Maury County wells. The chemical regeneration requirement is the main trade-off vs. a chemical-free AIO system.
Iron (high levels)ManganeseH&sub2;SHardnessBacteria
Removes / reduces
Strong performance on iron, hydrogen sulfide, and manganese at higher contaminant levels than Birm or standard catalytic carbon. Contains a high percentage of manganese dioxide for powerful oxidation. Works across a broader range of water conditions.
Does NOT remove
Hardness, nitrate, bacteria, organic chemicals. Very heavy media — requires higher backwash flow rates than other iron media. May need adequate dissolved oxygen or periodic chlorine injection depending on iron levels.
5–8 yrs
Media lifespan
Higher flow backwash
Maintenance note
MnO2 oxidation
How it works
Middle Tennessee use: Reserved for wells with higher iron levels (5–10+ ppm) where Birm has been insufficient. Also effective for manganese staining (black deposits on fixtures — distinct from iron’s orange). Wells in Rutherford and Wilson Counties often show combined iron and manganese.
Iron (high)H&sub2;SManganeseHardnessBacteria
Removes / reduces
Physical particles: dirt, sand, silt, rust, clay, and suspended particles. Available in 5, 10, 20, and 50 micron ratings. Protects downstream equipment (iron filters, softeners, RO membranes, UV lamps) from premature clogging and wear.
Does NOT remove
Dissolved contaminants of any kind: iron (dissolved ferrous), hardness, chlorine, chemicals, bacteria, PFAS. Only captures solid particles. Not a treatment system — a protection system for treatment systems.
3–12 months
Cartridge replacement
Always first stage
Sequence position
5–50 micron
Typical rating
Middle Tennessee use: Required as the first stage in every well water treatment system. Middle Tennessee’s spring and fall rains stir up silt in aquifers — pre-filter clogging increases after major rain events, especially in agricultural areas of Maury, Robertson, and Wilson Counties. A clogged pre-filter reduces house water pressure and shortens the life of everything downstream.
Sediment/siltSandRust particlesDissolved ironChemicalsBacteria
Removes / reduces
Arsenic III and Arsenic V via adsorption onto activated alumina, iron oxide, or proprietary media surfaces. Highly targeted. Often used in point-of-use or whole-house applications. Most effective at neutral to slightly acidic pH (6.5–7.5).
Does NOT remove
Iron, hardness, bacteria, nitrate, most other contaminants. Performance is affected by competing ions (phosphate, silica, fluoride at high levels). Requires pre-treatment if iron or turbidity is present — these compete for adsorption sites.
Highly variable
Media lifespan (by arsenic level)
pH 6.5–7.5
Optimal range
Monitoring required
Maintenance need
Middle Tennessee use: Relevant for private wells in areas with Cambrian or Ordovician bedrock formations where naturally occurring arsenic may be present. A baseline arsenic test is recommended for any deep bedrock well. RO also effectively removes arsenic — often the more practical choice for point-of-use protection.
Arsenic III & VIronHardnessBacteria
Removes / reduces
Nitrate via anion exchange — exchanges nitrate ions for chloride ions on the resin. Effectively targets agricultural nitrate contamination. Requires salt (sodium chloride) for regeneration. Targeted and effective for the specific problem of nitrate in drinking water.
Does NOT remove
Hardness (Ca/Mg), iron, bacteria, PFAS, or most other contaminants. Increases chloride levels in treated water. Does not soften water. Reverse osmosis is often a simpler solution providing broader contaminant coverage including nitrate.
5–8 yrs
Resin lifespan
Salt brine regen
Regenerant
Targeted
Best for
Middle Tennessee use: Relevant for agricultural-area wells in Robertson County (tobacco and row crops), Maury County (livestock and row crops), Wilson County, and Montgomery County where nitrate from fertilizer and septic effluent is a seasonal concern. For most households, RO provides nitrate reduction with broader coverage at the kitchen tap.
NitrateHardnessIronPFASBacteria
What these media do
Anthracite: Top layer in multi-media filters — low density, excellent dirt-holding, removes suspended solids and turbidity. Garnet: Bottom layer, high density, traps very fine particles. Zeolite: Moderate ion exchange — reduces ammonia, some heavy metals, good for turbidity. Together in layered filters: efficient mechanical filtration across a wide particle range.
What these media do NOT do
None remove dissolved contaminants, iron (dissolved), hardness, chlorine, bacteria, PFAS, or chemicals. These are strictly mechanical filtration media for physical particles. They do not address any water chemistry issue.
5–10+ yrs
Media lifespan (durable)
Periodic backwash
Maintenance
Pre-filtration
Primary role
Middle Tennessee use: Found in high-flow whole-house pre-filtration systems, particularly in commercial or farm applications with heavy turbidity loads. Zeolite’s ammonia reduction is relevant for agricultural-area wells in Robertson and Maury Counties. For most residential Middle Tennessee applications, a simple 5–20 micron cartridge sediment filter achieves equivalent pre-filtration goals at much lower cost.
TurbiditySuspended solidsAmmonia (zeolite)Dissolved contaminants
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Correct Treatment Sequences for Middle Tennessee

Filter order matters as much as filter choice. A wrong sequence can destroy equipment, reduce effectiveness, or void warranties. These are the five most common treatment configurations for Middle Tennessee homes.

Treatment Sequence Guide
Select your water source and situation
1
Sediment Pre-Filter
5–20 micron
→
2
Catalytic Carbon (Whole-House)
Chlorine, chloramine, TTHMs, HAAs
→
3
Water Softener
Optional — if GPG >7
→
4
Under-Sink RO
Optional — chromium-6, nitrate, PFAS, drinking water
Best for: Nashville, Franklin, Murfreesboro, Nolensville, Smyrna, Brentwood, La Vergne, Hendersonville, Gallatin, Clarksville, Lebanon, Mount Juliet, Springfield, Dickson city water. The whole-house catalytic carbon tank is the priority investment for all surface water utility customers.
1
Sediment Pre-Filter
5–20 micron spin-down
→
2
AIO Iron Filter
Ferrous iron, H&sub2;S, manganese
→
3
Water Softener
After iron is removed — hardness only
→
4
Carbon Filter
Taste, odor, post-chlorination cleanup
→
5
UV Sterilization
Final stage — kills bacteria
Critical rule: AIO iron filter ALWAYS before softener. Iron above 1 ppm fouls softener resin permanently. Best for: Williamson County rural wells, Maury County wells, Robertson County wells, Cheatham County wells.
1
Sediment Pre-Filter
Removes particles first
→
2
AIO System (Catalytic Carbon)
H&sub2;S aeration + catalytic carbon media removes sulfur and iron
→
3
Water Softener
Limestone hardness
→
4
UV Sterilization
Always last stage after all filtration
The rotten egg smell is unmistakable. Catalytic carbon in an AIO-type system handles both H&sub2;S and iron simultaneously. Best for: Williamson County deeper wells, Montgomery County wells, Dickson County wells with sulfur and iron.
1
Sediment Pre-Filter
Particles first
→
2
Acid Neutralizer
Raise pH to 7.0+ before iron filter
→
3
AIO Iron Filter
Now pH-corrected water allows proper iron oxidation
→
4
Water Softener
Hardness after iron removed
→
5
UV Sterilization
Bacteria — always last
pH correction is the most commonly skipped step that causes iron filter failures. Dickson County and Cheatham County chert/shale geology frequently produces acidic well water. Test pH before buying any iron filter.
1
Sediment Pre-Filter
Protects RO membrane
→
2
Carbon Pre-Filter
Remove chlorine before RO membrane
→
3
RO Membrane (NSF/ANSI 58)
PFAS, nitrate, chromium-6, all dissolved contaminants
→
4
Post-Carbon Polishing
Final taste and odor cleanup
→
5
Whole-House Carbon
Optional — for TTHMs at every shower and tap
Best for: Milcrofton UD and Spring Hill WD customers (PFOA above EWG). Also relevant as future insurance for all Middle Tennessee surface water customers. Always verify PFOA is specifically listed in NSF/ANSI 58 certification documentation.

Filter Effectiveness Quick Reference

Which media removes which contaminant. Use this alongside the detailed cards above for a fast overview.

Media / System Chlorine TTHMs / HAAs PFAS (PFOA, PFOS, PFBS, PFHxA, PFPeA) Iron H₂S Hardness Nitrate Chromium-6 Bacteria Arsenic Fluoride Barium Radium 226/228 Strontium Aluminum Atrazine Sediment
Activated Carbon (GAC) ✅ ✅ ✅ Partial ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ✅ ❌
Catalytic Carbon ✅ ✅ Partial Partial ✅ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ✅ ❌
Reverse Osmosis (RO) ✅ ✅ ✅ ✅ ❌ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅
Ion Exchange (Softener) ❌ ❌ ❌ Low level only ❌ ✅ ❌ ❌ ❌ ❌ ❌ ✅ ✅ ✅ ❌ ❌ ❌
KDF Media ✅ ❌ ❌ Partial ✅ ❌ ❌ Partial ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌
SP3 / NAC Conditioner ❌ ❌ ❌ ❌ ❌ Scale only ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌
AIO Iron Filter ❌ ❌ ❌ ✅ ✅ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌
UV Sterilization ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ✅ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌
Birm Media ❌ ❌ ❌ ✅ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌
Greensand Plus ❌ ❌ ❌ ✅ ✅ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌
Sediment Filter ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ✅
Nitrate Removal Resin ❌ ❌ ❌ ❌ ❌ ❌ ✅ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌
Arsenic Removal Media ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ✅ ❌ ❌ ❌ ❌ ❌ ❌ ❌
Acid Neutralizer ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌ ❌

Not Sure Where to Start?

The right filter sequence for your home starts with knowing what is actually in your water. Your utility’s Consumer Confidence Report and the Tennessee Water Authority city guide for your area are your starting point for city water. For well owners, a certified water test is the only reliable baseline.

1.
Find your city guide
Your utility’s guide shows exactly which contaminants are above EWG guidelines in your water. That list becomes your filter shopping checklist — the contaminants that need addressing drive your media selection.
2.
Well owners: test first, always
Before buying any well water treatment equipment, test for iron, pH, hardness (GPG), bacteria, and nitrate. These four results determine your entire treatment sequence. Testing costs $75–$150. Buying the wrong equipment costs $1,500–$5,000.
3.
Have a quote? Get a second opinion first
Tennessee Water Authority audits water treatment quotes for free. Upload your quote or water test and a local expert will confirm whether the system and price make sense for your specific water and zip code.

Know your water before you choose a filter.

Find your city guide or submit a quote for a free independent audit.

Get a free quote audit → Contaminants guide
Related guides
Certifications Guide → Contaminants Guide → Well Water Guide → Nashville Water Guide → Murfreesboro Water Guide → Bottled vs. Filtered Water → Free Quote Audit →