Review the annual water report
Municipal customers can start with the local Consumer Confidence Report to identify regulated substances and reported levels.
Choose a Water Filter by Water Concern
The right water filter depends on what is actually in the source water. A TDS reading, municipal report or laboratory test can narrow the choice, but each measurement answers a different question. Start with evidence, then compare the filter technology and model-level reduction information.
Test the Water Before Choosing a Filter
A filter cannot be matched accurately when the source-water problem is only assumed.
Use targeted laboratory testing
Private-well users and households concerned about a specific substance should use an appropriate certified laboratory test.
Treat TDS as a screening number
A TDS meter estimates dissolved substances but does not identify individual contaminants or prove that water is safe.
Match the result to model-level evidence
Compare the exact product’s test report, certification scope, filtration media and replacement requirements.
Find a Filter Path for Your Main Water Concern
These paths organize the technology and evidence to review. They do not replace a water test or the model’s verified reduction data.
High TDS
Reverse osmosis is generally the most relevant point-of-use technology for lowering total dissolved solids. Compare membrane performance, flow and remineralization preference.
Explore TDS Filters →Fluoride
Compare RO-based systems and confirm the exact model’s fluoride-reduction evidence, operating conditions and filter-replacement schedule.
Explore Fluoride Filters →Arsenic
Identify the arsenic level and form through appropriate testing, then compare systems with clear model-level evidence for the intended use.
Explore Arsenic Filters →PFAS / PFOA / PFOS
Look for product-specific testing or certification that names the PFAS substances covered. Generic carbon or RO descriptions are not enough.
Read PFAS Information →Lead and Heavy Metals
Review the exact standard, contaminant list, reduction claim and replacement conditions for the model being considered.
Review Certification Information →Chlorine Taste and Odor
Carbon-based faucet or under-sink filters may be a suitable starting point when the main goal is taste and odor improvement.
Compare Under-Sink Filters →Water Concern Selection Matrix
Use the matrix to decide which technology and evidence deserve the closest review.
| Concern | Useful starting information | Common technology path | Evidence to review |
|---|---|---|---|
| High TDS | TDS meter plus source-water context | Reverse osmosis | Model TDS performance, membrane specifications and operating conditions |
| Fluoride | Water report or lab result | Reverse osmosis or other verified media | Model-specific fluoride reduction test or certification |
| Arsenic | Laboratory result and water chemistry | Verified RO or specialized treatment | Named arsenic reduction evidence and test conditions |
| PFAS | Water report or targeted laboratory test | Verified carbon and/or RO solution | Exact PFAS compounds, test method and product scope |
| Lead | Water report plus household plumbing assessment | Verified carbon, RO or specialized media | Named lead reduction claim and replacement conditions |
| Taste / odor / chlorine | Sensory issue and local report | Carbon-based faucet or under-sink filter | Model’s chlorine taste-and-odor claim and filter life |
Representative Filter Paths
Compare Filters by Water Concern and Filtration Goal
These three products represent different filtration paths: a permanent under-sink RO system with model-level evidence to review, a no-installation countertop RO system and a non-RO ultrafiltration option that retains naturally occurring dissolved minerals.
Evidence-Led Under-Sink RO
PD1000-N Tankless Reverse Osmosis System
A permanent under-sink RO option for users comparing broader dissolved-solids reduction and model-specific evidence for named contaminants.
- Tankless 9-stage reverse osmosis design
- 0.0001-micron RO membrane with alkaline remineralization
- Smart faucet displays real-time TDS and filter status
- Review the current model report for each contaminant claim
No-Installation Countertop RO
WB99-C Countertop Reverse Osmosis System
A countertop RO option for apartments, offices and other spaces where drilling or permanent under-sink plumbing changes are not preferred.
- 0.0001-micron reverse osmosis membrane
- Plug-and-use design with no under-sink installation
- Alkaline post-filter for improved drinking taste
- Removable pitcher with TDS and filter-life display
Mineral-Retaining Non-RO
GX99 Under-Sink Ultrafiltration System
A non-RO ultrafiltration option for everyday municipal tap water when taste, sediment and particle filtration matter but lowering TDS is not the main goal.
- 0.01-micron ultrafiltration membrane
- Retains naturally occurring dissolved minerals
- Not designed for TDS reduction
- No electricity or RO-style drain-water process
Evidence reminder: Do not assume that every RO or ultrafiltration system addresses the same contaminants. Review the exact model number, named contaminant, test or certification scope, operating conditions and replacement requirements before choosing a product.
TDS Does Not Identify a Specific Contaminant
Total dissolved solids is a combined measurement of dissolved minerals, salts, metals and other substances. Two water samples can show a similar TDS number but contain very different substances. Use TDS to monitor general RO performance or compare source and filtered water—not as a substitute for contaminant testing.
Read Certification and Test Language Carefully
A whole-system certification, a certified component and an independent laboratory report are different forms of evidence. Review the model number, standard, contaminant, reduction level, capacity, flow and test conditions. Claims should be tied to the exact product and evidence source.
For Private Wells
Well water can change over time and may involve microorganisms, nitrates, arsenic, hardness, iron or other local conditions. Use a suitable laboratory test and professional treatment advice when the result involves a health-related contaminant or whole-house treatment need.
Frequently Asked Questions
Can one water filter remove every contaminant?
No single system should be assumed to address every possible substance. Choose from the source-water test and the exact model-level reduction evidence.
What type of filter is used for high TDS?
Reverse osmosis is commonly used for TDS reduction because the membrane separates many dissolved substances. Product performance still depends on operating conditions and model design.
Does a carbon filter remove fluoride?
Basic carbon filtration should not be assumed to reduce fluoride. Use a product with clear, model-specific fluoride reduction evidence.
How do I choose a filter for arsenic?
Start with a laboratory test, review the arsenic concentration and water chemistry, then select a system with evidence that applies to the exact model and use conditions.
Can RO reduce PFAS or lead?
Some RO systems may have model-specific evidence for named contaminants. Confirm the exact certification or laboratory report rather than relying on the general RO category.
Is better-tasting water proof that contaminants were removed?
No. Taste and odor improvement does not confirm reduction of a health-related contaminant.
Use Evidence to Narrow the Right Filter
Start with the water concern, then compare the exact model’s filtration technology, test information, flow and maintenance requirements.