California Code, Health and Safety Code - HSC § 7116

(a) Cremated remains or hydrolyzed human remains may be scattered in an area where no local prohibition exists, provided that the cremated remains or hydrolyzed human remains are not distinguishable to the public, are not in a container, and that the person who has control over disposition of the cremated remains or hydrolyzed human remains has obtained written permission of the property owner or governing agency to scatter on the property. A state or local agency may adopt an ordinance, regulation, or policy, as appropriate, authorizing, consistent with this section, or specifically prohibiting, the scattering of cremated human remains or hydrolyzed human remains on lands under the agency's jurisdiction. The scattering of the cremated remains or hydrolyzed human remains of more than one person in one location pursuant to this section shall not create a cemetery pursuant to Section 7003 or any other law.

(b) Commencing January 1, 2027, reduced human remains may be integrated into the soil in an area where no local prohibition exists, provided that the reduced human remains are not distinguishable to the public, are not in a container, and that the person who has control over disposition of the reduced human remains has obtained written permission of the property owner or governing agency to integrate into soil on the property. A state or local agency may adopt an ordinance, regulation, or policy, as appropriate, authorizing or specifically prohibiting the integration of reduced human remains into the soil on lands under the agency's jurisdiction. The integration into the soil of the reduced human remains of more than one person in one location pursuant to this section does not create a cemetery pursuant to Section 7003 or any other law.