California Code, Business and Professions Code - BPC § 17577.3

(a) A contract or offer which is subject to approval, for the sale, lease, or rental of a water treatment device shall be deemed a home solicitation contract or offer, as defined in subdivision (a) of Section 1689.5 of the Civil Code regardless of where the contract or offer was made, and shall be subject to the provisions of Sections 1689.5 to 1689.13, inclusive, of the Civil Code if the contract or offer arises out of a scheduled presentation to promote the sale, lease, or rental of a water treatment device to a person invited to attend the presentation at a location other than a private residence.

(b) A water treatment device or any other materials that are the subject of a contract offer described in subdivision (a) may be delivered and installed during the rescission period provided in Sections 1689.5 to 1689.13, inclusive, of the Civil Code.  Notwithstanding any other law, if a buyer exercises his or her right to rescind the contract in accordance with those rescission provisions, the seller shall be responsible for all costs in removing the installed water treatment device or any other materials and shall remove that device or any other materials within 20 days of the rescission.  If the seller's services result in the alteration of property of the buyer, the seller shall restore the property to substantially as good condition as it was at the time the services were rendered.

(c) A water treatment device or any other materials that are the subject of a contract offer described in subdivision (a) shall be delivered and installed in accordance with Section 7163 and the federal Truth in Lending Act (15 U.S.C. Sec. 1601 et seq.), as applicable.