What Counts as an “Essential Function” — and Who Gets to Decide
You can do the job with an accommodation. Your employer says you can’t — because the function the accommodation modifies is “essential.” The dispute over what is essential and what is not is the most litigated question in disability accommodation law, and the answer is not whatever the employer puts in the job description.
Every disability accommodation case turns on a single question: can the employee perform the essential functions of the job, with or without reasonable accommodation? If yes, the employer must accommodate. If no, the employer may not be required to.
The fight over this question is the fight over the word “essential.” The employer says the function is essential. The employee says it is not — or says it can be performed in a modified way. The outcome of the case depends on who is right.
What “essential functions” means
An essential function is a fundamental duty of the position — a task that is so central to the job that removing it would fundamentally alter the nature of the role. FEHA regulations define essential functions by reference to several factors: whether the position exists to perform the function; whether there are a limited number of other employees who can perform it; and whether the function is highly specialized.
A surgeon’s ability to operate is an essential function. A receptionist’s ability to answer phones is an essential function. A delivery driver’s ability to drive is an essential function. These are tasks without which the job does not exist.
But many functions that employers label “essential” are not. They are preferred. They are customary. They are convenient. They are the way the job has always been done. And they are not, under the legal standard, fundamental to the position.
The job description is evidence — not proof
Employers rely heavily on job descriptions to define essential functions, and FEHA regulations recognize the job description as relevant evidence. But the job description is not dispositive. It is one factor among several.
Courts also consider: the amount of time spent performing the function (a task that occupies five percent of the employee’s time is less likely to be essential than one that occupies fifty percent); the consequences of not performing the function (if the function can be reassigned without disrupting operations, it may not be essential); the work experience of past and current employees in the position (if previous incumbents did not perform the function, it is harder to argue it is essential); and the employer’s judgment (which is given weight but is not conclusive).
The employer’s judgment is considered, not accepted. An employer that revises a job description to add “must be present in the office full-time” after an employee requests remote work has not established that in-office presence was always essential. It has revised the description to defeat the accommodation request — and the timing of the revision is evidence of pretext.
The most common disputes
In-person attendance. The employer says physical presence is essential. The employee, whose disability makes commuting difficult, requests remote work. The employer argues that collaboration, supervision, and client interaction require the employee to be on-site.
This is the most frequently litigated essential-functions dispute. The answer depends on the specific job — but the employer’s own conduct is often the most powerful evidence. An employer that allowed the employee to work remotely during the pandemic — successfully, for an extended period — will have difficulty arguing that in-person presence was always essential. The employer’s own experience contradicts the argument.
Lifting and physical requirements. The employer says the job requires lifting fifty pounds. The employee, who has a back injury, can lift twenty-five. The question is whether the fifty-pound requirement is truly essential — whether the job genuinely requires it with sufficient frequency — or whether it is a general physical requirement that does not reflect the actual demands of the position.
Schedule flexibility. The employer says the job requires a specific schedule — early mornings, late evenings, rotating shifts. The employee, whose disability requires medical appointments during certain hours, requests a modified schedule. Whether the specific schedule is essential depends on the nature of the work: a teacher who must be present when students are present has a stronger essential-function argument than a data analyst whose work is not time-dependent.
Driving. The employer says the job requires driving. The employee, who has a visual impairment or a seizure condition, cannot drive. The question is whether driving is truly essential — whether the employee must personally operate a vehicle — or whether transportation to job sites could be accomplished through other means (a coworker driving, public transit, ride services).
The interactive process resolves the dispute
The essential-functions dispute is supposed to be resolved through the interactive process — the good-faith dialogue between employer and employee required by FEHA. The interactive process should include: a discussion of the job’s actual requirements (not just the job description but the day-to-day reality); an assessment of which functions are truly essential; an exploration of whether the essential functions can be performed with accommodation; and an evaluation of whether non-essential functions can be reassigned.
An employer that skips the interactive process and declares the function essential — without discussion, without exploration, without engaging with the employee’s perspective — has failed its obligation. The failure to engage is itself a violation, independent of whether the function was actually essential.
Why the employee’s perspective matters
The employee knows the job. In many cases, the employee has been doing the job for years — performing the functions, understanding which tasks are central and which are peripheral, and observing which functions can be modified or reassigned without affecting the operation.
The employer’s perspective — reflected in the job description, in the supervisor’s assessment, in HR’s determination — is one input. The employee’s perspective is another. The interactive process exists to bring both perspectives together and to reach a determination that is grounded in the reality of the work, not in the employer’s litigation position.
If your employer says a function is essential and refuses to accommodate you — without engaging in the interactive process, without evaluating whether the function can be modified or reassigned, without considering your knowledge of the actual job requirements — the determination may not hold up. Essential functions are defined by the reality of the work, not by the employer’s job description or litigation strategy.
This article is general information about California law and is not legal advice. Every situation turns on its particular facts.