CA Gov't Code Section 56886.6

The commission shall not impose a condition for the provision of services by the annexing city to an area which has not been placed within that city’s adopted sphere of influence, as defined in Section 56076, unless that condition would mitigate effects which are a direct result of the annexation. In the case of any annexation proposal for which a certificate of completion was not recorded prior to January 1, 1985, a condition imposed thereon which does not comply with the requirements of this section is null and void and shall not affect the validity of or terminate the annexation proceedings.