Health & Saf. Code, § 116785

Except as provided in Section 116786, a residential water softening or conditioning appliance may be installed only if either of the following apply:

(a) The regeneration of the appliance is performed at a nonresidential facility separate from the location of the residence where the appliance is used.

(b) The regeneration of the appliance discharges to the community sewer system and all of the following conditions are satisfied:

(1) The appliance activates regeneration by demand control.

(2) An appliance installed on or after January 1, 2000, shall be certified by a third party rating organization using industry standards to have a salt efficiency rating of no less than 3,350 grains of hardness removed per pound of salt used in regeneration. An appliance installed on or after January 1, 2002, shall be certified by a third party rating organization using industry standards to have a salt efficiency rating of no less than 4,000 grains of hardness removed per pound of salt used in regeneration.

(3) The installation of the appliance is accompanied by the simultaneous installation of the following softened or conditioned water conservation devices on all fixtures using softened or conditioned water, unless the devices are already in place or are prohibited by local and state plumbing and building standards or unless the devices will adversely restrict the normal operation of the fixtures:

(A) Faucet flow restrictors.

(B) Shower head restrictors.

(C) Toilet reservoir dams.

(D) A piping system installed so that untreated (unsoftened or unconditioned) supply water is carried to hose bibs and sill cocks that serve water to the outside of the house, except that bypass valves may be installed on homes with slab foundations constructed prior to the date of installation; or condominiums constructed prior to the date of installation; or otherwise where a piping system is physically inhibited.