Data Clean Rooms Explained: A 2026 Guide for Marketers

Data clean rooms have moved from an experiment to standard kit for large advertisers. An IAB and BWG Strategy study from February 2024 found that 66% of US data and advertising professionals had adopted one, citing privacy legislation and signal loss ¹. Yet the same research base shows the friction: in the 2025 State of Retail Media report, 39% of organisations said they struggle to turn clean room data into actionable insights ¹.

In September 2026 the IAB went further, publishing a framework that concludes most common commerce use cases can often be handled without a clean room at all ²³. So the useful question for a marketing leader is no longer "what is a clean room?" but "do we actually need one, and which?"

What a data clean room is

The IAB Tech Lab describes a clean room as a "secure collaboration environment which allows two or more participants to leverage data assets" under strict limits on access ¹. Each party brings its own data, such as a brand's CRM file or a retailer's purchase data, and privacy-enhancing technologies ensure neither side sees the other's raw records ¹.

Two broad types exist:

• Walled garden clean rooms, such as Amazon Marketing Cloud and Google Ads Data Hub, which generally limit analysis to that platform's own inventory ¹.
• Independent platforms, such as Snowflake, LiveRamp, InfoSum and AppsFlyer, which support collaboration across many partners and clouds ¹.

Third-party cookies are not the reason to rush. In October 2025 Google confirmed that Chrome will keep its current approach of offering users a choice over third-party cookies, and retired most Privacy Sandbox technologies, including Topics and Protected Audience ⁴. Clean rooms matter because of consent rules, platform data restrictions and the need to connect media to sales, not because a cookie deadline is looming.

The main platforms in 2026

Clean room	What it joins	Access and cost
Google Ads Data Hub	Your first-party data in BigQuery with Google event-level ad data 5	Through your Google account team or agency 5
Amazon Marketing Cloud	Amazon shopping, browsing and streaming signals with your data 6	Open to all sponsored ads advertisers; free access per EMARKETER 16
Snowflake Data Clean Rooms	Any partners' data held in or invited to Snowflake 7	Charged under your Snowflake contract, based on warehouse runtime 8
LiveRamp and other independents	Multi-partner, multi-cloud data 1	Implementation and licence fees 1

Google Ads Data Hub joins first-party data you upload to BigQuery with Google's event-level campaign data, and returns only results aggregated over groups of users ⁵. Privacy checks enforce this: rows need roughly 50 unique users under the legacy difference-check mode, about 20 under the recommended noise injection mode, and about 10 for queries using only click and conversion data ⁹. Data can be hosted in Europe (excluding London and Zurich), the US, Japan and Australia ⁵.

Amazon Marketing Cloud (AMC) became available to all advertisers running Sponsored Products, Sponsored Brands, Sponsored Display or Sponsored TV in September 2025, with no-code analysis templates alongside a SQL query editor ⁶. Amazon lists the UK, Germany, France, Saudi Arabia, the UAE and Egypt among its markets ⁶. From June 2026, Amazon's own paid signals, Amazon Audience Segment Insights and Amazon Retail Purchases, became free to query for audience creation and measurement until 31 December 2026, though third-party signals such as Experian's still carry a fee and Amazon has not said what happens from January 2027 ¹⁰.

Snowflake Data Clean Rooms let a provider create a room, define approved query templates and invite collaborators, who can join even without a Snowflake account ⁷. Stock templates cover audience overlap and reach and frequency, and exporting results requires approval from every party whose data is used ⁷. Snowflake is discontinuing its legacy version in favour of a newer Collaboration Clean Rooms experience. In August 2026 it removed LiveRamp, Acxiom, Merkury and PAIR identity connectors from the legacy web app; Google Ads and Meta Ads activation remain available through the Collaboration API ⁷¹¹.

IAB Tech Lab standards

Every retailer and platform runs its own room with its own requirements, which creates operational overhead ¹. The IAB Tech Lab has published three relevant documents ¹²:

1. Data Clean Rooms: Guidance and Recommended Practices 1.0 (July 2024), which sets common principles, functions and privacy-enhancing technologies, along with guardrails ¹².
2. ADMaP 1.0 (finalised February 2025), a protocol for sharing exposure and conversion data for attribution without revealing user-level details ¹².
3. PAIR 1.1 (finalised July 2025), which lets advertisers and publishers match encrypted first-party identifiers for audience activation. It superseded the earlier Open Private Join and Activation (OPJA) specification, now deprecated ¹².

When comparing vendors, ask whether they support PAIR and ADMaP, rather than accepting "interoperable" at face value ¹.

Use cases: where a clean room earns its keep

The IAB's September 2026 framework, Data Clean Rooms in Commerce, produced with BVDW, IAB Australia, IAB Canada and IAB Europe, sorts 14 commerce use cases into two groups ²³:

• Typically need a clean room (5): audience overlap analysis, data enrichment, bring-your-own-data targeting, suppression and exclusion, and retailer audience activation ³.
• Often achievable without one (9): including attribution, incrementality, reach and frequency, customer journey analysis, segmentation, lookalike modelling and media mix analysis ³.

The distinction is whether the data sits with different organisations. Attribution needs a clean room when exposure and purchase data are held by separate companies; reach and frequency needs one for cross-platform deduplication, but not within a single media environment ³. On incrementality, the framework states that "a DCR is unnecessary" when both data sets sit inside a retailer's own environment ³.

Retail media is the main driver, with closed-loop measurement the most established use case, though fewer than half (48%) of US retail media networks offered clean room capabilities in Q2 2025 ¹.

Privacy: a clean room is not a legal basis

Clean rooms reduce data exposure, but they do not make processing lawful on their own. The IAB framework says plainly that "the use of a data clean room does not, by itself, establish a legal basis for processing or sharing data" ³. The usual work on lawful basis, consent and partner contracts still has to be done before any data goes in.

The US Federal Trade Commission was blunter in November 2024, warning that "by default, most services that provide DCRs are not privacy preserving" and that they often "default to allow both parties full access to all of the data" ¹³. Thresholds, approved templates and export approvals create the protection, so someone on your side must own them.

Costs and skills

The costs are real. The IAB's State of Data 2023 report put the average clean room cost at $376,000 a year, with deployments taking up to two years, and found 49% of users had six or more dedicated staff ¹⁴. In a July 2024 Cint and Lotame study, 48% of marketers and agencies not planning to use clean rooms cited lack of budget ¹.

Skills are the other constraint: clean rooms require SQL and data science capability that many brands lack ¹. No-code templates in AMC and Snowflake help with standard reports ⁶⁷, but custom analysis still needs analysts.

Key takeaways

• Clean rooms let two or more parties analyse combined data without sharing raw records, but adoption has outpaced the ability to act on the results ¹.
• Walled garden rooms analyse one platform's data; independent rooms cover many partners but carry licence and implementation fees ¹.
• The IAB says only 5 of 14 commerce use cases typically need a clean room ³.
• PAIR 1.1 and ADMaP 1.0 are the IAB Tech Lab standards to ask vendors about ¹².
• A clean room is not a legal basis for processing, and default settings are often not privacy-preserving ³¹³.

What this means for your brand

If your analysis can be done inside one platform, use that platform's reporting or a free walled garden room such as AMC before paying for an independent build. Bring in an independent clean room when you need to combine data held by separate companies, for example deduplicated reach across platforms or matching your CRM against a retailer's audiences. Before signing, confirm PAIR and ADMaP support, the vendor's default privacy settings, and who on your team will write and govern the queries. If nobody can, budget for that capability first.

Sources

1. FAQ on data clean rooms: How retail media is driving adoption as marketers demand proof - EMARKETER, January 2026
2. Data Clean Rooms in Commerce: Common Use Cases - IAB, September 2026
3. IAB says 9 of 14 commerce use cases often work without a clean room - PPC Land, October 2026
4. Update on Plans for Privacy Sandbox Technologies - Google Privacy Sandbox, October 2025
5. ADH for Marketers - Google for Developers, accessed October 2026
6. Amazon Marketing Cloud now available to all advertisers running sponsored ads campaigns - Amazon Ads, September 2025
7. Overview of Provider and Consumer Clean Rooms - Snowflake Documentation, accessed October 2026
8. Snowflake Data Clean Rooms operational costs - Snowflake Documentation, accessed October 2026
9. Privacy checks in Ads Data Hub - Google for Developers, accessed October 2026
10. Amazon now lets AMC users query 1P paid features for free until end of 2026 - PPC Land, June 2026
11. Aug 20, 2026: Snowflake Data Clean Rooms updates - Snowflake Documentation, August 2026
12. Data Clean Rooms Guidance - IAB Tech Lab, July 2025
13. Data Clean Rooms: Separating Fact from Fiction - US Federal Trade Commission, November 2024
14. Data Clean Rooms Are Popular But Costly: IAB Report - CDP Institute (IAB State of Data 2023), January 2023

Figures and product details are as reported by the sources listed, at the time of writing. Platforms change quickly, so check the latest documentation before acting on any single number.