How Often Should You Really Change Your Water Filters? A South Florida Guide
By Jared Beviano | Water Wizards Filtration
I replaced a whole-house carbon filter last week in a home in Delray Beach. The homeowner—a guy named Rick who's lived in the house for about four years—asked me when the filter had last been changed.
I looked at the installation date written on the housing. March 2021.
That filter had been in there for almost four years. It was supposed to be changed annually.
When I pulled it out, the thing was basically a solid cylinder of compressed sediment and organic matter. The carbon inside—which should be loose granules that water flows through—had cemented into a dense mass. Water wasn't being filtered anymore. It was being forced through a clogged pipe.
"I had no idea," Rick said. "The water still tasted fine to me."
And that's the problem. By the time your water tastes bad, your filter hasn't just stopped working—it's been not working for months. Maybe longer. The taste change is the last symptom, not the first.
So let's talk about filter replacement schedules. Not the generic recommendations you see online, but what actually makes sense for South Florida specifically—because our water conditions are different from most of the country, and those differences matter.
Why South Florida Is Harder on Filters
Before I get into specific timelines, you need to understand why filters wear out faster here than the manufacturer estimates.
Most filter manufacturers base their replacement recommendations on average U.S. water conditions. They assume moderate chlorine levels, moderate sediment, moderate hardness, moderate everything.
South Florida doesn't do moderate.
We Have Aggressive Chlorination
Our year-round warm climate creates ideal conditions for bacterial growth in water distribution systems. To compensate, municipalities use aggressive chlorination—and most have switched from straight chlorine to chloramines, which are more persistent and harder to remove.
That carbon filter rated for "12 months" based on average chlorine levels? It's working twice as hard here. The carbon gets exhausted faster because there's more chlorine to absorb.
We Have High Sediment Loads
Between our sandy soil, aging infrastructure, and periodic water main repairs, South Florida water carries a lot of particulate matter. After a heavy rain, sediment levels spike. After utility work in your neighborhood, sediment levels spike. During dry season when water demand is highest, sediment levels spike.
Sediment filters that might last 6 months in other parts of the country can clog in 3 months here—sometimes faster if you're in an older neighborhood with aging pipes or near recent construction.
We Have Hard Water
Most of South Florida has moderately hard to very hard water, especially as you move west. Hard water doesn't directly affect filter life, but it does affect everything else in your system—and if you have a water softener upstream of your filters (which you should), the softener's demands affect overall system performance.
We Have Unique Contaminants
PFAS near airports. Agricultural chemicals in western areas. Sulfur and iron in well water. Saltwater intrusion near the coast. Each of these creates additional load on your filtration system that generic manufacturer timelines don't account for.
The Real Replacement Schedule: Filter by Filter
Alright, let's get specific. Here's what I actually recommend for South Florida homes, based on years of seeing what works and what fails.
Whole-House Sediment Filters
Manufacturer recommendation: 6-12 months
South Florida reality: 3-6 months
What I tell customers: Check it every 3 months, replace when visibly dirty or when you notice pressure drop.
Sediment filters are your first line of defense—they catch particles before they reach your other equipment. They're also the canary in the coal mine for your water quality.
A sediment filter that's clogging every 2 months tells you something about your water supply. Maybe there's construction in your area. Maybe your neighborhood has old pipes. Maybe the utility is doing work upstream. The filter is giving you information.
I've seen sediment filters in some Boca Raton homes last 6 months with no problem. I've seen sediment filters in certain parts of West Palm Beach need replacement every 8 weeks. Location matters enormously.
Cost: $15-40 per filter Signs it needs changing: Visible discoloration, pressure drop throughout house, filter feels heavy when removed
Whole-House Carbon Filters
Manufacturer recommendation: 12 months or 100,000-150,000 gallons
South Florida reality: 6-9 months for most households
What I tell customers: Change at 6 months if you have a larger family (4+ people) or high water usage. Change at 9 months for smaller households. Never go past 12 months regardless.
Carbon filters remove chlorine, chloramines, and a range of chemicals. They work through adsorption—contaminants stick to the carbon surface. Once that surface is saturated, the filter stops working. It doesn't give you a warning. It just stops.
The problem with waiting until your water "tastes like chlorine again" is that by then, you've been drinking inadequately filtered water for weeks or months. Chlorine taste is the last thing to return because it takes significant filter failure before enough chlorine gets through to be noticeable.
Here's something most people don't realize: an exhausted carbon filter can actually release contaminants back into your water. Once the carbon is saturated, the chemical bonds that hold contaminants to the surface can break down, dumping accumulated stuff back into the water flow. You end up with water that's worse than if you had no filter at all.
Cost: $80-200 depending on housing size and carbon type Signs it needs changing: Calendar says it's time (don't wait for symptoms), chlorine smell returning, TDS readings increasing
Catalytic Carbon Filters (for Chloramine Removal)
Manufacturer recommendation: 12 months
South Florida reality: 6-12 months depending on chloramine levels
What I tell customers: Test your water's chloramine level at 6 months. If it's creeping up, change the filter. If levels are still low, you can push to 9-12 months.
Catalytic carbon is specifically designed to handle chloramines, which standard carbon doesn't remove effectively. Since most South Florida utilities use chloramines, this distinction matters.
Catalytic carbon costs more than standard carbon, so there's a financial incentive to maximize filter life. But the testing approach gives you actual data rather than guessing.
Cost: $120-300 depending on system Signs it needs changing: Chloramine test shows breakthrough, reaching time limit
Under-Sink Carbon Filters
Manufacturer recommendation: 6-12 months
South Florida reality: 6 months for most households
What I tell customers: Set a calendar reminder and change at 6 months. Don't overthink it.
Under-sink filters process a lot less water than whole-house systems—you're only filtering what comes through one faucet. But that water is going directly into your body, so the stakes are higher.
At $30-60 per filter, the cost of changing every 6 months instead of pushing to 12 months is maybe $40-50 per year. That's trivial compared to the cost of drinking inadequately filtered water.
Cost: $30-60 per filter Signs it needs changing: Calendar says so, flow rate decreasing, taste changing
Reverse Osmosis Pre-Filters (Sediment and Carbon)
Manufacturer recommendation: 6-12 months
South Florida reality: 6 months, possibly more often
What I tell customers: Change both pre-filters every 6 months. They're protecting your expensive RO membrane.
RO systems typically have two or three pre-filters before the membrane: a sediment filter and one or two carbon filters. These pre-filters do the heavy lifting of removing particles and chlorine before water reaches the delicate RO membrane.
If you neglect the pre-filters, two bad things happen. First, contaminants reach the membrane that shouldn't, shortening its life. Second, the pre-filters clog and reduce flow, causing the system to work harder and produce less water.
Pre-filter replacement is the most important maintenance you can do for an RO system. It's also the cheapest—pre-filters run $15-40 each. The membrane they're protecting costs $80-150.
Cost: $15-40 per filter (usually 2-3 filters) Signs they need changing: Reduced water production, calendar reminder
RO Membrane
Manufacturer recommendation: 2-3 years
South Florida reality: 2-3 years IF you're changing pre-filters on schedule
What I tell customers: Test your TDS annually. If rejection rate drops below 90%, replace the membrane. Otherwise, replace at 3 years maximum.
The RO membrane is the heart of a reverse osmosis system—it's what actually removes dissolved contaminants. It's also the most expensive component to replace.
Membrane life is almost entirely determined by how well you maintain your pre-filters. I've seen membranes last 5 years in systems where pre-filters were changed religiously. I've seen membranes fail in 18 months where pre-filters were neglected.
The way to know if your membrane is still working is to test the water. Measure TDS (total dissolved solids) going into the system and coming out. A healthy membrane removes 90-99% of TDS. If you're seeing only 70-80% removal, the membrane is failing.
Cost: $80-150 Signs it needs changing: TDS rejection below 90%, water tastes different, membrane is past 3 years
RO Post-Filter (Polishing Filter)
Manufacturer recommendation: 12 months
South Florida reality: 12 months
What I tell customers: Change it when you change your pre-filters the second time each year, or annually at minimum.
The post-filter is the final stage—it polishes the taste of RO water after it leaves the storage tank. It's the least critical filter in the system because by the time water reaches it, most contaminants are already removed.
That said, an old post-filter can add taste and odor back into your water, undoing some of what the system accomplished. It's cheap enough ($20-40) that annual replacement makes sense.
Cost: $20-40 Signs it needs changing: Annual schedule, taste issues with RO water
UV Bulbs
Manufacturer recommendation: 12 months or 9,000 hours
South Florida reality: 12 months, no exceptions
What I tell customers: Replace annually even if the bulb is still glowing. UV output decreases before the bulb visibly fails.
UV systems kill bacteria and viruses by exposing water to ultraviolet light. The bulb's UV output—not its visible light output—is what matters. A bulb can glow for years while its UV effectiveness drops to near zero.
If you're on well water and relying on UV for bacterial safety, bulb replacement isn't optional. You can't see UV light, so you can't tell by looking whether your system is still protecting you. The only safe approach is time-based replacement.
Some UV systems have sensors that measure actual UV output and alarm when it drops too low. These are great—but even with a sensor, I recommend annual replacement because sensors can fail too.
Cost: $80-150 depending on system Signs it needs changing: Annual schedule, UV alarm (if equipped), lamp visibly dimming
UV Quartz Sleeve
Manufacturer recommendation: 2-3 years
South Florida reality: 2 years, possibly annually in hard water areas
What I tell customers: Inspect annually when you change the bulb. Replace if you see any cloudiness, film, or scaling.
The quartz sleeve is the glass tube that separates the UV bulb from the water. It needs to be crystal clear for UV light to penetrate effectively. Any film, mineral buildup, or cloudiness blocks UV transmission and reduces effectiveness.
In South Florida's hard water, mineral deposits on quartz sleeves are common. If you're in an area with particularly hard water and don't have a softener upstream of your UV system, you might need to clean or replace the sleeve annually.
Cost: $40-80 Signs it needs changing: Visible cloudiness or film, mineral deposits, approaching 2 years
Water Softener Resin
Manufacturer recommendation: 10-15 years
South Florida reality: 8-12 years, less if chlorine levels are high or if system runs dry
What I tell customers: If your softener is 10+ years old and you're noticing hard water breakthrough despite proper salt levels and regeneration, it's probably time for resin replacement.
Softener resin doesn't need regular replacement like filters—it regenerates during each cycle. But it does degrade over time, especially when exposed to chlorine (which attacks the resin beads) or when run without salt (which exhausts the resin without regenerating it).
I've seen resin last 15 years in well-maintained systems with good pre-filtration. I've seen resin fail at 6 years in systems that repeatedly ran out of salt or had high chlorine exposure.
Cost: $250-400 for professional resin replacement Signs it needs changing: Hard water despite adequate salt and regeneration, softener is 10+ years old, resin beads visible in plumbing
The Maintenance Schedule Nobody Follows (But Should)
Let me give you a realistic maintenance calendar based on what I've told you above. I'm assuming a typical South Florida home with a whole-house carbon filter, water softener, and under-sink RO system.
Monthly
Check water softener salt level (add if below half full)
Quick visual inspection of equipment for leaks
Every 3 Months
Check whole-house sediment filter (replace if visibly dirty)
Check water pressure (drop may indicate filter clogging)
Every 6 Months
Replace whole-house sediment filter (if not replaced at 3 months)
Replace under-sink carbon filter
Replace RO pre-filters (sediment and carbon)
Check whole-house carbon filter (consider replacement at high usage)
Annually
Replace whole-house carbon filter
Replace RO post-filter
Replace UV bulb (if applicable)
Inspect UV quartz sleeve (if applicable)
Test water quality (TDS, hardness, chlorine)
Professional system inspection (recommended)
Every 2-3 Years
Replace RO membrane (or when testing shows degradation)
Replace UV quartz sleeve
Every 8-12 Years
Evaluate water softener resin condition
Assess overall system age and consider upgrades
The Cost of NOT Changing Filters
I know filter replacement feels like an ongoing expense that's easy to defer. "It's probably fine for another month" is something I hear constantly. So let me explain what deferred filter maintenance actually costs you.
Scenario 1: Neglected Whole-House Carbon Filter
Filter cost: $150 Recommended replacement: Every 9 months Actual replacement: Every 2 years (common)
What happens: After 12-15 months, the carbon is exhausted. Chlorine passes through unimpeded. Your water heater, dishwasher, washing machine, and other appliances are now getting chlorinated water that accelerates rubber seal degradation. The anode rod in your water heater corrodes faster.
The real cost:
Water heater fails 2-3 years early: $1,200-2,000
Dishwasher seal failure: $150-300 repair
Washing machine issues: $100-400
Dry skin and hair requiring additional products: $200/year
Total cost of "saving" $150 by not changing filter: Easily $1,500-3,000 over the life of your appliances.
Scenario 2: Neglected RO Pre-Filters
Filter cost: $50-80 for the set Recommended replacement: Every 6 months Actual replacement: "When I remember" (often 12-18 months)
What happens: Pre-filters clog, reducing flow. More importantly, they allow chlorine and sediment to reach the RO membrane. Membrane life drops from 3 years to 18 months.
The real cost:
Extra membrane replacement: $100-150
Reduced water production during the decline period: Inconvenience
Potential contaminant breakthrough: Health risk
Total cost of "saving" $80: An extra $100-150 in membrane costs, plus the hassle of premature replacement. You actually spend more money, not less.
Scenario 3: Neglected UV Bulb
Bulb cost: $100 Recommended replacement: Annually Actual replacement: "It's still glowing, so it's fine" (often 2-3 years)
What happens: UV output drops below effective levels while the bulb still produces visible light. Bacteria pass through undetected. If you're on well water, you're drinking water with potential bacterial contamination.
The real cost:
Best case: Nothing happens, you got lucky
Worse case: Gastrointestinal illness for you or family members
Worst case: Serious infection in immunocompromised family member
This isn't a cost calculation—it's a risk calculation. Is saving $100/year worth the gamble with bacterial safety?
How to Actually Remember Filter Changes
Knowing when to change filters is one thing. Actually remembering to do it is another.
Option 1: Calendar Reminders
Set recurring reminders on your phone or calendar app. Every 6 months for RO pre-filters. Every 9 months for whole-house carbon. Annually for UV bulbs. Simple, free, and effective if you actually act on the reminders.
Option 2: Sticker System
Write the installation date and next-change date on a sticker attached to each filter housing. When you open the cabinet or look at the system, the information is right there. Low-tech but effective.
Option 3: Filter Subscription Service
Some companies (including us) offer automatic filter delivery on a schedule. Filters show up at your door when it's time to change them. You don't have to remember anything—the arrival of the box is your reminder.
Option 4: Maintenance Contract
A professional maintenance plan means we show up on schedule and handle everything. You don't think about filters at all. Most expensive option, but also most foolproof.
Option 5: Smart Monitoring
Some newer filtration systems have sensors that track water flow and estimate filter life. They send notifications to your phone when filters need changing. The technology is getting better, but it's still not perfect—I recommend using smart monitoring as a supplement to time-based schedules, not a replacement.
When to Change Filters Early
Everything I've told you so far is based on normal conditions. But sometimes you should change filters before the schedule says to.
After Major Weather Events
Hurricanes, tropical storms, and heavy flooding can contaminate water supplies and increase sediment loads dramatically. If your area experienced significant weather and your water looks, smells, or tastes different, change your filters—especially sediment filters—regardless of how recently you changed them.
After Utility Work
Water main repairs, hydrant flushing, and other utility work stirs up sediment in the distribution system. If you notice discolored water after utility work in your neighborhood, run your taps until the water clears, then check your sediment filter. It may have caught a significant load and need early replacement.
After Construction Nearby
New construction, especially anything involving excavation, can introduce sediment into the water system. If there's major building activity near your home, keep an eye on your sediment filter.
When You Notice Symptoms
Chlorine taste returning. Pressure dropping. Water looking cloudy. Any symptom that suggests filter failure means it's time to check and probably replace, regardless of the calendar.
When Testing Shows Problems
If you test your water and see that chlorine is getting through your carbon filter, or TDS rejection is dropping on your RO system, don't wait for the scheduled change—replace now.
The Bottom Line
Filter replacement isn't glamorous. It's not exciting. It's easy to ignore because the consequences of neglect aren't immediately obvious.
But proper filter maintenance is the difference between a water treatment system that actually protects you and one that's just taking up space in your garage.
Here's the short version:
Sediment filters: Every 3-6 months in South Florida
Whole-house carbon: Every 6-9 months
Under-sink carbon: Every 6 months
RO pre-filters: Every 6 months
RO membrane: Every 2-3 years (test annually)
RO post-filter: Annually
UV bulbs: Annually, no exceptions
The money you "save" by extending filter life beyond these intervals costs you more in the long run—through damaged equipment, shortened appliance life, and degraded water quality.
Change your filters. Your water, your appliances, and your body will thank you.
Need Help Staying on Schedule?
Water Wizards offers filter subscription services and maintenance plans throughout Palm Beach and Broward counties. We'll send you filters when it's time to change them, or we'll come out and handle everything for you.
Call 561-352-9989 or visit waterwizards.ai to learn about our filter programs.
Water Wizards Filtration — Florida's Water Filtration Experts
Serving Delray Beach, Boca Raton, West Palm Beach, Jupiter, Wellington, Boynton Beach, Fort Lauderdale, and communities throughout South Florida.
Frequently Asked Questions: Water Filter Replacement
How do I know what type of filters my water filtration system uses?
Check the filter housing for a model number, or look at your system's documentation from installation. Most whole-house systems use standard 10" or 20" cartridges (measured by length) in either 2.5" or 4.5" diameter housings. The filter housing itself usually has the size printed on it. For RO systems, the brand and model determine which filters fit—most manufacturers use proprietary cartridges. If you can't identify your filters, take a photo of your system and the existing filters, then call your water treatment company or bring the photo to a water treatment supply store. We can identify most systems from photos and help you get the right replacement filters.
Can I clean and reuse water filters instead of replacing them?
Sediment filters can sometimes be rinsed and reused once or twice in an emergency, but this isn't recommended for regular maintenance—you're not removing the embedded particles, just the surface layer. Carbon filters cannot be cleaned or regenerated at home; once the carbon is saturated with contaminants, it needs replacement. RO membranes can be cleaned with specialized solutions to extend life, but this is a temporary measure, not a permanent solution. UV bulbs cannot be "cleaned" to restore UV output—once output drops, replacement is the only option. In general, filters are consumable items designed for replacement, not reuse. The cost savings from attempting to reuse filters isn't worth the risk of inadequate filtration.
Why does my water still taste fine even though the filter is past its replacement date?
Taste is the last thing to change when a filter fails—not the first. Carbon filters remove chlorine through adsorption (contaminants stick to carbon surface), and this process can continue at reduced effectiveness even when the filter is largely exhausted. By the time enough chlorine gets through to affect taste, your filter has been underperforming for weeks or months. More concerning, some contaminants that carbon removes—like certain pesticides, PFAS, and disinfection byproducts—have no taste at all. Your water can taste perfectly fine while these contaminants pass through an exhausted filter. This is why time-based replacement schedules matter more than taste-based decisions. Don't wait until your water tastes bad; change filters on schedule.
What happens if I use the wrong filter for my system?
Using incorrect filters can cause several problems: physical fit issues (filter doesn't seal properly, allowing unfiltered water to bypass), inadequate filtration (wrong micron rating or media type), reduced flow rate (filter too restrictive for your system's design), or system damage (forcing incompatible filters into housings). For whole-house systems with standard housings, you have flexibility in filter brand and type as long as dimensions match. For RO systems, use manufacturer-specified filters or verified compatible alternatives—RO fittings and connections are less forgiving. When in doubt, contact your water treatment provider with your system's make and model. Using the correct filters ensures your system performs as designed and maintains warranty coverage.
Is it worth paying more for premium water filters?
For most South Florida applications, yes—premium filters typically offer better performance and longer effective life. High-quality carbon filters use coconut shell carbon (more porous, better adsorption) versus coal-based carbon. Premium sediment filters use gradient density (captures more particles without clogging quickly). Better RO membranes have higher rejection rates and longer service life. The price difference between budget and quality filters is usually $10-30 per filter, but quality filters often last 20-30% longer while providing better contaminant removal throughout their life. That said, "premium" isn't always better—some expensive filters are overpriced for what they deliver. NSF certification is more important than price; a certified mid-range filter outperforms an uncertified expensive one. We recommend quality filters from established brands with documented performance specifications.
Do water filter subscription services actually save money?
Filter subscription services typically cost about the same or slightly more than buying filters yourself, but they provide value beyond just the filters. You get correct filters automatically delivered on an appropriate schedule, eliminating the risk of buying wrong filters or forgetting to change them. Many subscriptions include reminders and instructions for filter changes. Some include discounts on service calls or annual inspections. The real value is consistency—subscription customers change filters on schedule because the filters arrive when it's time to change them. Customers who buy filters themselves often delay purchases, extend filter life too long, and end up with degraded water quality. If you're disciplined about filter changes, buying yourself works fine. If filters tend to slip your mind, subscriptions provide built-in accountability that's worth the modest premium.
How do South Florida's water conditions affect filter life compared to other regions?
South Florida's conditions significantly reduce filter life compared to manufacturer estimates, which assume national average water quality. Our aggressive chlorination (and chloramines) exhausts carbon filters 25-50% faster than moderate-chlorine regions. High sediment loads—from sandy soil, aging infrastructure, and seasonal variation—clog sediment filters in 3-4 months versus the 6-12 months seen elsewhere. PFAS contamination near airports creates additional load on carbon filters designed to remove it. Hard water, while not directly affecting filter life, requires properly functioning softeners upstream—if your softener fails, hard water accelerates scale buildup everywhere. For practical planning, assume South Florida filter life is about 60-75% of manufacturer recommendations. A filter rated for 12 months should be replaced at 6-9 months here. This isn't manufacturer deception—it's just that their testing doesn't account for our uniquely challenging water conditions.
