These are some rules in Colorado Statutes regarding pre-ex: Notice section III (In Colorado, Kaiser fits into section III - perhaps the rules are similar in your state)
10-16-118. Limitations on preexisting condition limitations.
Statute text
(1) A health coverage plan that covers residents of this state:
(a) (I) If it is a group health benefit plan, shall not deny, exclude, or limit benefits for a covered individual because of a preexisting condition for losses incurred more than six months following the date of enrollment of the individual in such plan or, if earlier, the first day of the waiting period for such enrollment; except that, for business groups of one, a health benefit plan shall not deny, exclude, or limit benefits for a covered individual because of a preexisting condition for losses incurred more than twelve months following the date of enrollment of the individual in such plan. A group health benefit plan may impose a preexisting condition exclusion or limitation only if such exclusion relates to a condition (whether physical or mental), regardless of the cause of the condition, for which medical advice, diagnosis, care, or treatment was recommended or received within six months immediately preceding the date of enrollment of the individual in such plan or, if earlier, the first day of the waiting period for such enrollment; except that a group health benefit plan shall not impose any preexisting condition exclusion in the case of a child that is adopted or placed for adoption before attaining eighteen years of age, or relating to pregnancy.
(II) If it is an individual health benefit plan, or a group health coverage plan to which subparagraph (I) of this paragraph (a) does not apply, shall not deny, exclude, or limit benefits for a covered individual because of a preexisting condition for losses incurred more than twelve months following the effective date of coverage and may not define a preexisting condition more restrictively than an injury, sickness, or pregnancy for which a person incurred charges, received medical treatment, consulted a health care professional, or took prescription drugs within twelve months.
(III) If it is a health maintenance organization that does not utilize preexisting condition limitations in any health benefit plan, may impose an affiliation period. An affiliation period shall run concurrently with any waiting period. Such a health maintenance organization may, in lieu of an affiliation period, use an alternative method to address adverse selection with the prior approval of the commissioner.
(b) Shall waive any affiliation period or time period applicable to a preexisting condition exclusion or limitation period for the period of time an individual was previously covered by creditable coverage if such creditable coverage was continuous to a date not more than ninety days prior to the effective date of the new coverage. The period of continuous coverage shall not include any waiting period for the effective date of the new coverage. This paragraph (b) shall not preclude application of any waiting period applicable to all new enrollees under the plan. The method of crediting and certifying coverage shall be determined by the commissioner by rule.
