Iron and Hydrogen Sulfide in South Florida Well Water: How to Fix It

If your private well west of Florida's Turnpike smells like rotten eggs or stains your sinks and laundry orange, you are dealing with two of the most common water quality problems in South Florida: hydrogen sulfide and iron. Wells in western Palm Beach County, western Broward County, and Martin County tap the Floridan Aquifer, which naturally carries dissolved hydrogen sulfide gas and ferrous iron at levels that make untreated water unpleasant and damaging to fixtures. The smell is not a safety emergency, but it is a signal that your water needs treatment before it reaches your taps, water heater, and appliances. This guide explains where the contamination comes from, how a properly sequenced treatment system removes it, what lab tests to run before sizing any equipment, and what installed treatment costs in South Florida look like today. Verify all cost figures with a licensed installer before purchasing.

Why Does South Florida Well Water Smell Like Rotten Eggs?

The rotten egg odor in South Florida well water is hydrogen sulfide gas (H2S), produced by sulfur-reducing bacteria living in the aquifer or your well casing, and by dissolved sulfur compounds naturally present in the Floridan Aquifer formation. Both sources are common west of the Turnpike.

The Floridan Aquifer underlies most of Florida and much of the Southeast. In western Palm Beach County, western Broward County, and Martin County, the upper Floridan is the primary drinking water source for private wells. That aquifer sits in limestone and dolomite formations that are rich in naturally occurring sulfate minerals. As groundwater moves through those formations over centuries, sulfate-reducing bacteria convert dissolved sulfates into hydrogen sulfide gas. The result is water that smells like rotten eggs even before it reaches your plumbing.

There are two distinct sources to understand. The first is dissolved H2S in the aquifer itself, which arrives at your wellhead already carrying the odor. The second is a colony of sulfur-reducing bacteria that may have established itself inside your well casing or pressure tank. Both produce the same smell, but the treatment approach differs. A lab test that measures hydrogen sulfide at the wellhead (before any treatment) versus at the tap tells you which source is dominant. The Florida Department of Environmental Protection private well testing guidance recommends testing at both points when odor is present.

Sulfur odor is most noticeable when you run the hot water tap. Heating drives dissolved H2S gas out of solution faster than cold water does, which is why the smell in the shower is often much stronger than at the cold kitchen tap. If you notice the smell only from the hot side, your water heater anode rod may be reacting with low-level sulfur in the water to amplify the odor. That is a separate diagnostic step, but it is worth noting before sizing a whole-home system, since the solution is different (replace the magnesium anode with an aluminum-zinc rod).

In older agricultural areas of western Broward and the Redland region west of Homestead, historical fertilizer use has added nitrate loading to shallow wells on top of the natural sulfur chemistry. If your well draws from above the confining layer, ask your lab to run nitrate alongside the sulfur panel.

What Causes High Iron in South Florida Private Well Water?

South Florida well water contains iron in two forms: dissolved ferrous iron (Fe2+), which makes water look clear at the tap but leaves orange stains as it oxidizes, and particulate ferric iron (Fe3+), which gives water an orange or rust color immediately from the tap. Both come from the Floridan Aquifer's iron-rich limestone and are common in wells west of the Turnpike.

Ferrous iron is the more common and more misunderstood form. The water looks completely clear when it pours, so homeowners sometimes assume their water is fine. Within minutes of air exposure, dissolved ferrous iron oxidizes to ferric iron, which is insoluble and drops out of solution as reddish-brown particles. Those particles are what stain your toilet bowl, bathtub, laundry, and dishwasher racks orange. Some wells in western Palm Beach County and Martin County test above 5 mg/L of dissolved iron, which is well above the EPA's secondary maximum contaminant level of 0.3 mg/L for iron (a taste and staining guideline, not a health limit).

Particulate ferric iron arrives at the tap already orange. This is less common in the Floridan Aquifer but appears in shallow wells or wells with corrosion inside the casing. It is easier to see but responds to different treatment than dissolved iron.

Manganese (Mn) often travels alongside iron in the same aquifer formations. Manganese stains black or dark purple rather than orange and is regulated at a lower secondary MCL of 0.05 mg/L. Ask your lab to measure manganese on any iron panel because a system sized only for iron will not adequately remove manganese at higher concentrations. The USGS has documented iron and manganese co-occurrence in Florida aquifer studies available at the USGS Florida Water Quality program.

Colloidal iron is a third form to know about, though it is less common in private wells. Colloidal particles are too small to settle on their own and can pass through standard sediment filters. If your water tests for iron but your current filter does not seem to be removing it, a colloidal iron test helps clarify whether a different media type is needed.

How Do You Remove Iron and Hydrogen Sulfide From Well Water?

The proven treatment sequence for South Florida well water with iron and hydrogen sulfide is: sediment pre-filter, then an oxidizing filter (SoFlo installs the Kenai AirOxPro), then KDF and carbon media, then UV purification. Sequence matters because each stage prepares the water for the next and skipping steps causes downstream media to fail prematurely.

Step 1: Get a Lab Test Before Buying Anything

The most important step in treating iron and hydrogen sulfide is the one that happens before any equipment is purchased. A certified lab test tells you the exact concentrations you are dealing with, which determines which media types you need and what flow rate your system must handle. A system sized for 1 mg/L of iron will be overwhelmed by 8 mg/L of iron within a few months.

For iron and related metals, request EPA Method 200.8 analysis. This inductively coupled plasma mass spectrometry test accurately measures iron, manganese, arsenic, and a full metals panel simultaneously. For bacteria, request IDEXX Colilert, the standard quantitative test for total coliform and E. coli that provides a result in 24 hours. Both tests are available through state-certified Florida labs. Our water testing service can coordinate sample collection and overnight shipping to a certified lab and help you interpret the results before sizing a system.

Step 2: Sediment Pre-Filter

A 20 to 50-micron sediment cartridge filter installed at the wellhead protects the oxidizing stage from sand, grit, and large suspended particles. This is especially important in Martin County wells and wells near agricultural areas in western Palm Beach County, where aquifer disturbance from irrigation pumping can introduce higher-than-normal sediment loads. Replace the cartridge on the schedule your water quality dictates, not the one printed on the box.

Step 3: The Kenai AirOxPro Oxidizing Filter

SoFlo Water Pros installs the Kenai AirOxPro as the primary iron and hydrogen sulfide removal stage. The AirOxPro is an air-injection oxidizing filter that works by introducing a pocket of air at the top of the tank before each service cycle. As water flows through that air pocket, dissolved ferrous iron and hydrogen sulfide gas are oxidized on contact. Ferrous iron converts to insoluble ferric particles that are then trapped in the greensand or catalytic media bed below. Hydrogen sulfide gas is driven off in the air pocket and vented rather than passing through your plumbing.

The AirOxPro uses no chemical injection (no potassium permanganate, no chlorine) for most iron and sulfur concentrations found in South Florida wells, which means no chemical storage or handling at the wellhead. For very high iron levels above 10 mg/L or heavy hydrogen sulfide above 2 mg/L, the system can be paired with a low-dose chlorination stage upstream for pre-oxidation. The Kenai control head allows the backwash and air recharge cycle to run automatically overnight, typically every three to five days depending on well output and iron concentration.

The AirOxPro is sized in cubic feet of media to match the iron load and daily water demand of the household. A well producing 2 mg/L of iron for a family of four needs a smaller vessel than a Martin County irrigation well at 6 mg/L. Proper sizing comes directly from the lab test result. Read more on the iron and sulfur removal service page for system configurations SoFlo runs in the field.

Step 4: KDF and Carbon Media Stage

After the oxidizing stage, water passes through a KDF (kinetic degradation fluxion) and catalytic carbon media tank. KDF media uses a copper-zinc redox reaction to reduce residual chlorine (if a pre-chlorination stage was used), remove trace heavy metals, and suppress bacterial regrowth in the media bed. Carbon removes taste, odor, volatile organic compounds, and any residual hydrogen sulfide gas that passed through the oxidizing stage. Together, these two media produce clear, odor-free water headed to the UV stage.

Step 5: Kenai UVPro Ultraviolet Purification

UV purification is the final stage and is covered in more detail in the section below. The Kenai UVPro is installed after all filtration stages so the water passing the UV lamp is already clear and particle-free. Particles in the water shield bacteria from UV exposure, so running UV on unfiltered well water dramatically reduces its effectiveness.

After installation, the full sequence delivers water that passes iron staining tests, is free of rotten egg odor, and has a bacteria count that meets drinking water standards. Check the well water overview page for a comparison of what untreated Floridan Aquifer water looks like before and after this treatment sequence.

Do South Florida Wells Need UV Purification?

Yes. South Florida private wells routinely test positive for total coliform bacteria and occasionally for E. coli. UV purification with the Kenai UVPro is the most reliable point-of-entry disinfection method for well water that does not involve adding chemicals to your drinking water supply.

Unlike city water, private well water receives no ongoing disinfection between the aquifer and your tap. Sulfur-reducing bacteria and other organisms that produce the rotten egg smell are one indicator that biological activity is occurring in your well system. Those bacteria are typically not pathogenic, but their presence is a reliable sign that the well casing, piping, or aquifer is supporting bacterial growth. A well that passes a bacteria test today may fail after the next heavy rain, after a nearby irrigation pump is disturbed, or after any disturbance to the well casing.

The Kenai UVPro operates at a 254-nanometer ultraviolet wavelength, which is the germicidal band that disrupts bacterial DNA and prevents reproduction. At a properly engineered flow rate, the UVPro delivers a dose of 40 mJ/cm2 or higher, which meets NSF Standard 55 Class A requirements for disinfection of untreated water supplies. The lamp sleeve must be cleaned annually and the lamp replaced every 9,000 hours of operation (roughly one year of continuous use) to maintain rated output. SoFlo includes a lamp replacement reminder with every UVPro installation.

UV does not remove iron, manganese, hydrogen sulfide, or any dissolved minerals. It only addresses biological contamination. That is why position in the treatment sequence matters: the UVPro goes last, after the water is clear and particle-free. A UV lamp shining through orange-tinted iron-laden water has a fraction of the disinfection effectiveness it has on clear water. If you have an existing UV system installed before an iron filter, the iron filter must come first in the line for the UV to work correctly. See the UV purification service page for sizing tables and lamp specifications.

For wells that test positive for E. coli specifically, UV alone may not be sufficient if contamination is ongoing. A positive E. coli result means fecal contamination has entered the well, which can point to a failing casing seal, surface drainage infiltration, or a nearby septic system. In that case, shock chlorination of the well casing plus a UV system is the correct response, and we recommend re-testing 30 days after shock chlorination to confirm the source of contamination has been addressed. Run a water checker lookup by address to see whether DEP has flagged any known well contamination events in your zone.

How Much Does Well Water Treatment Cost in South Florida?

A complete iron and hydrogen sulfide treatment system for a South Florida private well typically costs $3,000 to $8,000 installed, depending on iron concentration, daily water demand, number of treatment stages, and site access conditions. Verify current pricing with a licensed installer before budgeting; material costs fluctuate and these ranges reflect field estimates as of mid-2026.

The wide range reflects real differences in what South Florida wells produce. A well at 1 to 2 mg/L of iron with mild hydrogen sulfide and a clean bacteria test may need only a properly sized AirOxPro and a Kenai UVPro. A well at 6 to 10 mg/L of iron with strong H2S and a positive coliform test needs a sediment pre-filter, a larger-vessel AirOxPro, a KDF/carbon polishing stage, and a high-output UVPro. The equipment and labor cost difference between those two scenarios is real and significant.

Here is how the cost typically breaks down across the stages a South Florida well treatment system requires.

Annual operating costs after installation are modest. The AirOxPro media bed typically needs replacement every 5 to 10 years depending on iron load. Carbon media in the polishing tank lasts 3 to 5 years. The UV lamp needs annual replacement at roughly $80 to $150 per lamp. Sediment cartridges at the pre-filter stage may need changing every 1 to 6 months depending on how much sand your well produces.

Financing is available through SoFlo Water Pros for qualified homeowners. See the water testing page to start with the lab test, or go directly to the contact page to schedule a no-cost on-site assessment. Our technicians carry a field iron test kit and can give you a ballpark at the visit before the lab results come back.

For homeowners weighing a whole-home approach that also addresses hardness and chloramine from a supplemental city water backup connection, the South Florida whole-home water filtration guide covers the combined system architecture. The well water page has a service-area map showing which South Florida zones SoFlo covers.

Frequently Asked Questions

Is hydrogen sulfide in well water dangerous to drink?

At the concentrations typically found in South Florida private wells, hydrogen sulfide is primarily an aesthetic problem (odor and taste) rather than an acute health hazard. The EPA does not set a health-based maximum contaminant level for hydrogen sulfide in drinking water. That said, high H2S levels are corrosive to copper plumbing and water heater components and indicate the presence of sulfur-reducing bacteria that should be addressed. Treat it, but do not panic.

Why does my water smell fine from the cold tap but awful from the hot?

Heat drives dissolved hydrogen sulfide gas out of solution faster than cold water does, making the odor much more noticeable at the showerhead or hot sink. Additionally, a magnesium anode rod inside your water heater can react with even low levels of sulfur to produce amplified odor downstream. Replacing the magnesium anode with an aluminum-zinc anode often reduces or eliminates hot-side odor even before full treatment is installed.

Can I just shock-chlorinate my well instead of installing a system?

Shock chlorination kills bacteria inside the well casing and is the correct first step when a bacteria test comes back positive. It does not remove dissolved iron, dissolved hydrogen sulfide gas, or ongoing contamination from the aquifer itself. Shock chlorination is a one-time disinfection procedure, not an ongoing treatment. For wells with iron above 0.3 mg/L or persistent H2S odor, a permanent treatment system is the correct long-term answer.

How long does a Kenai AirOxPro installation take?

A single-day installation is standard for most South Florida residential wells. The crew arrives with the full system pre-assembled, connects the vessels to the existing supply line, sets the Kenai control head to your water chemistry parameters, and commissions the system with a post-installation water run. You have treated water the same day. Allow two days if the site requires new bypass valving, an electrical upgrade for the UVPro ballast, or significant wellhead plumbing reconfiguration.

Will iron treatment also fix my water's hard water scaling?

Not directly. The Kenai AirOxPro treats dissolved and particulate iron and hydrogen sulfide. It does not soften water or remove calcium and magnesium that cause scale. Many South Florida wells are moderately hard in addition to having iron issues. If your lab test shows hardness above 7 grains per gallon (about 120 mg/L) and you are seeing scale on fixtures or in the water heater, a salt-based softener or a salt-free conditioner installed downstream of the AirOxPro addresses the hardness side of the problem separately.

How do I know if my Martin County well needs UV in addition to iron treatment?

An IDEXX Colilert test is the definitive answer. If your well tests positive for total coliform bacteria (even without E. coli), a UV system is warranted. In Martin County and older agricultural areas of western Palm Beach County, where shallow wells and older casings are common, we recommend UV as a standard component of any new iron treatment system rather than waiting for a positive bacteria test. The cost of the UVPro stage relative to the total system is low, and the protection is continuous once installed.

Related reading

Related: Iron and sulfur removal service · UV purification · Water testing · Well water overview · South Florida whole-home filtration guide · Water checker by address · Contact and free assessment · Service area · FAQ · About SoFlo Water Pros