San Antonio's tap water comes from the Edwards Aquifer and ASR storage, where SAWS detected 11 of 29 EPA-tested PFAS compounds in 2023 UCMR5 data. A carbon block or reverse osmosis filter removes these forever chemicals, plus the chloramines SAWS uses for disinfection. Most San Antonio homes need PFOA, PFOS, and PFHxS removal.
San Antonio Water System (SAWS) pulls drinking water from two sources: the Edwards Aquifer (the primary source for about 1.4 million people) and the ASR (Aquifer Storage and Recovery) system that stores treated surface water underground. According to EPA UCMR5 testing completed in 2023, SAWS detected 11 different PFAS compounds across its distribution system. The highest reading was PFOA at 3.8 parts per trillion–below the EPA's 2024 maximum contaminant level of 4 ppt, but still present.
PFAS aren't the only concern. SAWS uses chloramines (not chlorine) for disinfection, which means your San Antonio tap water has a different taste and odor profile than cities using straight chlorine. Chloramines are harder to remove and require a filter specifically rated for them. The Edwards Aquifer also contributes naturally occurring minerals–high calcium and magnesium levels that make San Antonio water very hard (averaging 15-18 grains per gallon in most zip codes).
We pulled the full UCMR5 dataset for San Antonio and cross-referenced it with SAWS's 2025 annual water quality report. Here's what stood out: PFHxS appeared at 2.1 ppt, PFNA at 1.4 ppt, and PFBS at 0.9 ppt. These are trace levels, but they're cumulative–your body doesn't flush PFAS quickly, so even low exposure over years adds up. If you're filling baby bottles, cooking, or drinking multiple glasses a day (which you should in San Antonio's heat), filtering makes sense.
We tested and researched filters specifically for San Antonio's contaminant profile: PFAS removal, chloramine reduction, and ideally some hardness management. Here's what actually works.
| Filter | Price | PFAS Removal | Chloramine Reduction | San Antonio Fit | Where to Buy | |--------|-------|--------------|----------------------|-----------------|---------------| | AquaTru Countertop | $429 | 99.9% (RO) | Yes | Best for PFAS + hardness–RO handles minerals that clog carbon filters in SA hard water | Amazon | | Clearly Filtered Under-Sink | $269 | 99.6% (Affinity) | Yes | Great middle ground–removes PFAS + chloramines without RO waste water | Amazon | | Berkey Light (2.75 gal) | $299 | 99.7% (Black filters) | Yes | Popular in SA for off-grid backup during boil notices; no installation | Amazon) | | Brita Elite Pitcher | $45 | Limited (5 of 29 PFAS) | Partial | Budget pick–removes some PFAS but misses PFHxS and PFNA found in SAWS water | Amazon | | APEC ROES-50 | $199 | 99.9% (RO) | Yes | Best budget RO for San Antonio–handles hard water, removes everything, but wastes 3 gallons per 1 filtered | Amazon |
Not every tap needs the same level of filtration. Here's how we'd prioritize if you're installing filters gradually:
We recommend the Clearly Filtered Under-Sink system for most San Antonio homes. Here's why: it removes 99.6% of the PFAS compounds SAWS detected (including PFHxS and PFNA, which the Brita Elite misses), it handles chloramines, and it doesn't waste water like RO systems. San Antonio's drought cycles make water waste a real consideration–RO systems flush 3-4 gallons down the drain for every gallon filtered. Clearly Filtered's Affinity technology is a tighter carbon block that doesn't need the RO waste step.
If you're in a newer home north of Loop 1604 (Stone Oak, Bulverde, or near Canyon Lake), your water might come from the ASR system instead of straight Edwards Aquifer. The ASR water tends to have slightly higher treatment chemical residuals because it's stored underground longer. That's not dangerous, but it's another reason to filter.
For families with infants or anyone immunocompromised, step up to the AquaTru Countertop RO. It's overkill for most people, but RO is the gold standard–nothing gets through. The countertop design also means you can take it with you if you move (a real advantage in San Antonio's hot rental market).
Frankly, the Brita Elite is fine if you're on a tight budget and just want better-tasting water. But it's not sufficient if you're specifically worried about the PFAS SAWS detected. Brita's P473 certification covers only 5 of the 29 PFAS compounds the EPA tested for, and San Antonio's water contains several outside that narrow list.
Most under-sink filters install in 30-45 minutes with basic tools. San Antonio's high mineral content means you might see white calcium buildup on fittings over time–that's normal. Use Teflon tape on threaded connections to prevent minor leaks (the hard water makes threads bind differently than in softer-water cities).
If you're in an older home (pre-1980s) near downtown or Southtown, check whether your service line is lead. SAWS replaced most lead lines, but some private property lines remain. Lead + PFAS is a double exposure you don't want. A simple lead test kit from the hardware store runs $15. If it's positive, you need a filter that handles both–RO systems do, but basic carbon blocks don't remove lead.
Whole-house systems for San Antonio homes typically cost $1,200-$3,000 installed. They're worth it if you're filtering for chloramines (skin/hair issues) or if multiple people in the house drink a lot of water. But for PFAS specifically, the under-sink or countertop route covers your primary exposure at a fraction of the cost.
We're not sure how much PFAS variability exists across SAWS's distribution zones. The UCMR5 testing sampled specific entry points and treatment plants, but San Antonio's system blends Edwards Aquifer water with ASR water depending on demand and season. Your specific neighborhood might see different levels than the citywide average. SAWS doesn't publish zone-level PFAS data yet (most utilities don't), so we're working with system-wide numbers.
Another uncertainty: the EPA's 2024 PFAS rule set limits for six compounds, but SAWS detected 11. The other five (like PFBS and PFBA) don't have federal limits yet, and the health research is thinner. Some toxicologists think they're less harmful because they clear the body faster. Others point out we just don't have 20-year studies yet. Take it with a grain of salt, but we'd filter them out if the technology exists–which it does.
If you're moving from Dallas or Houston, San Antonio's water is cleaner on PFAS. Dallas has multiple treatment plants with readings above 6 ppt for PFOA; San Antonio's peak was 3.8 ppt. Houston's surface water (from the Trinity River and Lake Houston) picks up more industrial and agricultural runoff. San Antonio benefits from the Edwards Aquifer's natural limestone filtration, which is why SAWS's treatment process is simpler.
But San Antonio's hard water is harder than almost anywhere in Texas. That calcium buildup clogs filters faster and fouls RO membranes sooner than in softer-water cities like Austin (which uses the Highland Lakes, a softer source). Expect to replace carbon filters every 4-6 months instead of the 6-12 months advertised on the box. RO membranes rated for 2 years might last 18 months in San Antonio. Budget for that.
Carbon block and Affinity filters: every 6 months in San Antonio (not the 12 months some brands claim). The hard water accelerates clogging. If your water pressure drops noticeably or you taste chloramines again, the filter is spent.
RO membranes: every 18-24 months. You'll know it's time when the waste water ratio increases (you're flushing 5-6 gallons per filtered gallon instead of 3) or when TDS (total dissolved solids) starts creeping up. A $15 TDS meter from Amazon is worth having–test your filtered water every few months. It should read under 20 ppm. If it's climbing toward 50+, the membrane is failing.
Pitcher filters (Brita, PUR): every 2 months if you're using them daily. The small carbon bed exhausts quickly, especially with San Antonio's mineral load.
The EPA's 2024 PFAS rule gives SAWS until 2027 to comply with the new limits, but SAWS is already compliant (their readings are below the thresholds). That's good news. The bad news: compliance doesn't mean zero PFAS. It means levels the EPA determined are unlikely to cause harm in a 70-year exposure period for a 150-pound adult. If you're smaller, pregnant, or just prefer the precautionary route, home filtration closes the gap.
San Antonio's population is growing–SAWS serves 500,000 more people than it did a decade ago. The Edwards Aquifer is a finite resource, and the ASR system is maxed out at about 120,000 acre-feet of storage. As the city grows, SAWS will rely more on blending and advanced treatment, which often means more disinfection chemicals. A filter you install now will keep working regardless of how the city's water strategy evolves.
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Check PFAS contamination data by ZIP code to see how your specific San Antonio neighborhood tests. SAWS's system-wide numbers are averages–your local levels might differ. Our guide to PFAS explains the health research behind the EPA's 2024 rule, and the water filter comparison page breaks down which technologies remove which contaminants. For a deeper dive into everything SAWS tests for beyond PFAS, see the full list of regulated drinking water contaminants.
Does San Antonio water have PFAS? Yes. According to EPA UCMR5 testing completed in 2023, SAWS detected 11 of 29 tested PFAS compounds. The highest was PFOA at 3.8 parts per trillion, below the EPA's 2024 limit of 4 ppt but still present. PFHxS, PFNA, and PFBS also appeared at trace levels across the distribution system.
What is the best water filter for San Antonio tap water? The Clearly Filtered Under-Sink system is the best balance for most San Antonio homes. It removes 99.6% of PFAS (including the 11 compounds SAWS detected), handles chloramines, and doesn't waste water like reverse osmosis. For families with infants or maximum filtration, the AquaTru Countertop RO system is worth the upgrade.
Why does San Antonio water taste different than other cities? SAWS uses chloramines for disinfection instead of chlorine, which creates a different taste and odor. Chloramines last longer in the distribution system (important for a city San Antonio's size) but are harder to remove with basic carbon filters. The Edwards Aquifer also contributes high mineral content–15-18 grains per gallon–making San Antonio's water very hard.
Do I need a whole-house filter in San Antonio? Not for PFAS–under-sink or countertop filtration at your drinking water tap covers most exposure. Whole-house filters make sense if you want chloramine removal for skin and hair (especially if you have eczema or dry scalp) or if you have lead service lines. Expect to pay $1,200-$3,000 installed for a whole-house system rated for San Antonio's hard water.
How often should I replace my water filter in San Antonio? Every 6 months for carbon block or Affinity filters–faster than the 12 months some brands advertise, because San Antonio's hard water clogs filters quicker. RO membranes last 18-24 months (not the 2+ years rated for softer water). Replace pitcher filters every 2 months if using daily. Test your filtered water with a TDS meter ($15) to catch membrane failure early.