The BHSA Transition Guide Part 6: ISL Implementation & Data Modernization

In our previous post, we explored the reporting and performance expectations under the Behavioral Health Services Act (BHSA). As the sixth installment in our BHSA Transition Guide series, we now turn to a substantial new county requirement: reporting individual service level (ISL) data by January 1, 2027.

DHCS now requires counties to collect and report non-Medi-Cal person-level encounter data at a more granular level than before. Previously, with only Medi-Cal claims data, DHCS saw just a fraction of the investments counties make to serve their communities. ISL codes are intended to provide a more complete picture of the services and support counties fund to serve individuals in their behavioral health systems.

This post addresses:

What is Individual Service Level (ISL) data?
What has changed from previous reporting requirements?
What does this mean for county operations?
How can EVALCORP help with ISL data compliance?

Counties may choose to submit ISL data early for services delivered between July 1 and December 31, 2026. Early submissions mean that this requirement is a planning opportunity—counties that begin capturing individual-level service data before the January 2027 mandate will be better positioned when required reporting takes effect.

As always, EVALCORP remains committed to helping our county partners navigate this BHSA and ISL transition thoughtfully and strategically, ensuring alignment with state expectations while addressing local behavioral health needs.

What is Individual Service Level (ISL) Data?

Individual Service Level, or ISL, is the county reporting requirement for non-Medi-Cal person-level encounter data under BHSA.

Effective January 1, 2027, behavioral health providers must capture and submit all BHSA ISL encounter data to DHCS for all applicable services and expenses—using DHCS-defined ISL codes or Medi-Cal CPT/HCPCS codes where a billing equivalent exists.

ISL encounters will not generate payment from DHCS. Instead, ISL data will support performance measures, population health management, and fiscal oversight in BHSA reporting. The goal is to capture the full cost of care across county-funded and non-Medi-Cal services, making visible the gap between what Medi-Cal claims show and what counties are actually investing in their communities. Overlaying this with performance data will also empower counties to better manage care.

When Does ISL Reporting Take Effect?

The ISL encounter reporting requirement is included in county performance contracts effective July 1, 2026, with required submission for all in-scope services delivered on or after January 1, 2027. Counties may begin optional early submission for services delivered between July 1 and December 31, 2026.

What Has Changed From Previous Requirements?

The California Mental Health Services Authority (CalMHSA) describes ISL requirements as a significant shift in how counties document their work. For the first time, counties and providers must capture service information at the individual level—not just what was funded—but who received it, what they received, and how it was used.

Before ISL, DHCS could only see a fraction of behavioral health investments through Medi-Cal claims, leaving county-funded services and other non-Medi-Cal activities largely outside the statewide data picture. ISL will be used to unify and holistically report those services so the state can understand what counties are actually investing and delivering across funding sources.

BHSA significantly expanded the scope of behavioral health services to include housing, recognizing that stable housing is inseparable from behavioral health recovery. ISL includes multiple codes for tracking housing services and expenses, including board-and-care patches, rental subsidies and landlord outreach. Statewide performance measures will use ISL data to evaluate BHP performance and establish accountability for BHSA goals.

Who Needs to Report and What Must Be Reported?

ISL reporting is required of all county contractors and providers who deliver services included in the BHSA reporting framework. When a Medi-Cal CPT/HCPCS code already exists for a service, providers use that code. For services and expenses that fall outside existing claims-based structures, DHCS has created a new set of ISL-specific codes. These include:

Acute: State hospital stays, crisis stabilization, 1:1 or 2:1 monitoring, and non-billable administrative days
Subacute: Skilled nursing facility, mental health rehab center, and IMD placements
Housing: Board and care, respite residential, rental subsidies, landlord outreach and mitigation, and participation assistance
Outpatient: Non-billable meetings, legal documentation, and outreach and engagement
Expenses: Food, clothing, hygiene, transportation, employment and education supports, child care, medication costs, and translation and interpreter services

What Does this Mean for County Operations?

ISL implementation will affect contracting, data collection, and reporting workflows across county behavioral health systems. Counties will need to assess not only what services are delivered, but whether their providers have the systems needed to capture them accurately.

Successful implementation depends on three things:

1. Identifying which services must be reported. Counties need to know which contractors and programs are in scope; for programs serving at-risk or community-based populations, that determination requires a program-by-program review rather than a blanket approach.

2. Determining which providers are ready to report. Counties will need to update contract terms so that impacted providers are responsible for meeting ISL standards and identify which codes apply to each program. Provider readiness varies considerably: community-based organizations without EHR access, programs serving anonymous or drop-in populations, and providers delivering group or community-level services face distinct implementation challenges that require tailored solutions. This work also requires coordination across finance, clinical, and data teams to ensure that service definitions, documentation requirements, and reporting expectations are aligned without creating unnecessary administrative burden.

3. Confirming whether existing systems can support the requirement. Data readiness depends on whether contractors have EHRs, tracking tools, or manual workflows, and whether those systems can produce a DHCS-ready data extract. Providers with EHR access may be able to configure existing systems to capture ISL data, while others will need a standalone data collection tool. Both pathways require planning, training, and quality assurance before the January 2027 deadline.

How Can EVALCORP Help Your County With ISL Data Compliance?

EVALCORP provides a phased set of services as part of our data utility assessment and planning support to help counties prepare for reporting, strengthen data infrastructure, and translate data into actionable decisions.

Our services include:

Readiness assessment and service landscape mapping, to identify which programs and providers are in scope, which ISL codes apply, and where data collection gaps exist — including an equity baseline to ensure marginalized populations are accurately represented.
ISL code crosswalks and standardized data collection tools to support consistent reporting across providers, including program-specific guidance on code applicability.
EHR systems review to identify what needs to be added, modified, or mapped to meet ISL reporting requirements, and to support providers without EHR access in building alternative data collection workflows.
Pre-submission data validation to identify and resolve reporting issues prior to compliance deadlines.
ISL data analysis and reporting, including synthesis of findings into a county-level investment and impact narrative.

Our BHSA Compliance and Integration Workgroup is actively tracking ISL developments and providing hands-on support to counties across California. From community engagement strategy development to data system design and outcome reporting, EVALCORP is ready to support you through every stage of this transition.

Please contact us to learn how we can support your county’s ISL implementation.

“If you can’t measure it, you can’t improve it.“

– Peter Drucker

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