Water Filter Systems: AI Visibility Market Discovery Index

Benchmark Summary

Questions This Section Answers

• Who leads the Water Filter Systems benchmark, and by how much?
• Which brands posted the largest recommendation coverage gains and declines since July 2026?

Aquasana led the Water Filter Systems benchmark in October 2026 with 57.6% valid recommendation coverage. The gap to the next brand, iSpring at 50.2% in October 2026, was 7.4 points. The month's largest coverage increase belonged to Brita, which rose to 46.3% in October 2026 from 35.0% in July 2026, a move beyond normal month-to-month variation. The largest coverage decline belonged to iSpring, which fell to 50.2% in October 2026 from 59.4% in July 2026, also beyond normal variation.

No brand posted a significant month-over-month move in October 2026; every change from September 2026 sat within normal variation. Across the full series, Brita climbed in each of the three months since July 2026, while Berkey and APEC Water Systems each declined in each of the three months since July 2026. Aquasana eased in September 2026 before recovering in October 2026, retaining the category lead throughout the series. Three brands recorded significant cumulative gains: Brita, Clearly Filtered, and Culligan. Two recorded significant cumulative declines: Berkey and iSpring.

The benchmark began with 800 prompt-surface observations in each month and produced 713 qualified observations in October 2026 after qualification.

Current Benchmark at a Glance

Qualified surface breadth counts the canonical AI/search surface families with at least one qualified observation: ChatGPT, Copilot, Gemini, Perplexity, AI Overviews, and AI Mode. All six families were represented in every month of the series. August 2026 and September 2026 sat between these two points; Aquasana peaked at 58.9% in August 2026 before easing to 53.4% in September 2026 and rising again to 57.6% in October 2026, a level above September but still below the August peak.

For the strategic interpretation of this benchmark, read CiteWorks Studio's analysis of How AI Search Is Recommending Water Filter Systems

Research Scope and Qualification

Questions This Section Answers

• How many of the 800 prompt-surface observations qualified for the public benchmark?
• Why do brand-level percentages use qualified observations rather than the raw collection?

The public benchmark is narrower than the raw collection universe by design.

Brand-level percentages use the qualified observations as the public denominator, not the raw collection. See the AI Visibility Market Discovery Methodology for the full qualification process.

Current Brand Standings

Questions This Section Answers

• Which water filter brands have the highest valid recommendation coverage?
• How do presence rate and valid recommendation coverage differ across the tracked brands?

This table is the primary current-month benchmark view, sorted by valid recommendation coverage.

How to Read the Standings

Presence rate is the share of qualified observations where a brand is mentioned at all. Valid recommendation coverage is the share of qualified observations where a brand receives a recommendation that fits the query. Top-three rate is the share where a brand appears in the first three recommended positions. Rank-one rate is the share where a brand is the first recommendation. Net sentiment is the balance of positive over negative mention sentiment. For formulas and denominator rules, see AI Visibility Market Discovery Metric Definitions.

Recommendation Coverage Movement

Questions This Section Answers

• Which brands gained the most recommendation coverage since the July 2026 baseline, and which lost the most?
• Did Aquasana's September dip and October recovery change its position as category leader?

Aquasana added 4.2 points from September 2026 to October 2026, a within-normal-variation move that returned the brand above its September 2026 dip, though still short of its August 2026 peak of 58.9%. Clearly Filtered and Culligan each eased from their September 2026 peaks, down 3.7 points and 2.0 points respectively month over month. Pentair moved up 1.5 points from September 2026 to October 2026 and held flat against its July 2026 baseline.

Largest Increase: Brita

Brita rose 11.3 points to 46.3% in October 2026 from 35.0% in July 2026, a move beyond normal month-to-month variation. The increase was accompanied by a 19.1-point gain in top-three rate to 29.7% and a 5.7-point gain in rank-one rate to 8.4%. Presence rate rose 6.6 points to 64.0%. Brita had 330 valid recommendations out of 713 observations in October 2026.

Largest Decline: iSpring

iSpring fell 9.2 points to 50.2% in October 2026 from 59.4% in July 2026, a move beyond normal month-to-month variation. The decline was accompanied by a 12.7-point drop in presence rate to 54.4%. The brand held 358 valid recommendations out of 713 observations in October 2026, and its rank-one rate of 13.5% remained the second highest in the benchmark.

Category Leader: Aquasana

Aquasana led the benchmark at 57.6% in October 2026, up 2.2 points from 55.4% in July 2026. The brand also recorded the highest presence rate at 65.5% and held 411 valid recommendations out of 713 observations. Aquasana's top-three rate rose 14.1 points to 47.1% in October 2026 from 33.0% in July 2026, and its rank-one rate rose 3.5 points to 13.3% over the same period.

Recommendation Placement Snapshot

Questions This Section Answers

• Which water filter brand is most often recommended first, and how does that differ from coverage rank?
• How did top-three and rank-one placement shift for Aquasana, iSpring, and Brita since July 2026?

Coverage alone does not show how prominently a brand is recommended. Among the leading brands, placement rates varied meaningfully.

Similar coverage levels can still hide different first-position rates. APEC Water Systems reached first position in 14.7% of observations in October 2026, the highest rank-one rate in the benchmark, while its valid recommendation coverage of 33.5% placed it seventh.

Buyer-Intent Distribution

Questions This Section Answers

• Which buyer-intent classes are measured in this benchmark?
• Are pricing and multi-brand comparison questions included in the current public series?

All qualified observations in every month of the series fell into the Brand Recommendation class.

The current public series measures brand recommendation discovery only and does not yet contain qualified observations in the Pricing & Value or Multi-Brand Comparison classes.

Historical Measurement Record

Questions This Section Answers

• Has Aquasana led the benchmark in every measurement period?
• Which brand recorded the largest coverage movement in each month of the series?

This is an evergreen benchmark URL. New measurements are added to the same report.

Evidence and Source Layer

Questions This Section Answers

• What data does each prompt-level observation retain?
• Does a source appearing in AI citations prove it caused the recommendation?

The benchmark is built from prompt-level observations that retain the query, AI/search surface, answer, brand outcome, recommendation placement, sentiment, and, where exposed, citations or attributable evidence sources. Source presence is evidence about the information environment. It is not automatically proof that the source caused the recommendation.

Scope Boundaries

This public benchmark does not measure market share, attributable sales, every possible AI response, organic-search ranking, social mention volume, or private and sponsored channels. A metric movement alone does not establish causality.

Top 10 Cited Domains

Questions This Section Answers

• Which domains are cited most often in AI responses about water filter systems?
• How concentrated are citations across the top 10 domains?

Across all AI platform responses in the October 2026 measurement period, 8,506 citations were observed across 1,103 unique domains.

The top 10 domains account for a combined 37.7% of all citations, indicating that citations are distributed across a wide range of sources rather than concentrated in a few. Aquasana's own domain, aquasana.com, is the only tracked brand domain in the top 10, cited 282 times and reaching five of the six platform families. The list is dominated by third-party review and testing sites such as waterfilterguru.com, consumerreports.org, techgearlab.com, and goodhousekeeping.com, alongside general video, search, retail, and community platforms.

About This Benchmark

The LLM Authority Index AI Visibility Market Discovery Index tracks how brands appear across major AI and search surfaces through structured, prompt-level observation. Canonical research links:

• AI Visibility Market Discovery Methodology
• AI Visibility Market Discovery Metric Definitions
• AI Visibility Market Discovery Research Standards
• Modeled AI Visibility Authority Value

Get a Company-Level Authority Index

The public industry benchmark shows category-level standings. A company-level Authority Index can go deeper.

Get my free AI Company Index