California Code, Health and Safety Code - HSC § 6550.7

If prior to the conclusion of the hearing written protests against the formation of the proposed improvement district or the proposed project signed by the current holders of title to taxable property within the proposed improvement district which, as shown by the last equalized assessment roll, constitutes more than one-half of the total assessed value of taxable property within the proposed improvement district, are filed with the district board, further proceedings relating to the proposed improvement district and the proposed project shall be terminated and no proceedings for the formation of any improvement district to undertake the proposed project shall be instituted for a period of six months following the date of the conclusion of the hearing.

Where taxable property is owned in joint tenancy, tenancy in common, or any other multiple ownership, the first one of such owners who signs the written protest shall commit all such property to the protest.