In the Field · Part 4
Water treatment: where softeners are restricted in California, filtration, pressure regulators, and thermal expansion
Hard water is most of California, so softeners and filters are a steady add-on for a residential plumber, and they are the one product category the state lets local sanitation agencies ban. Health and Safety Code 116786 allows a local agency to prohibit self-regenerating softeners that discharge brine to the sewer where it finds the salt is a water-quality problem, and the Santa Clarita Valley did exactly that. This lesson covers the restriction and how to check it, the difference between a softener, a conditioner, and a filter and what each does and does not do, the drain and backflow rules that every treatment installation must meet, and the two devices that belong on every high-pressure house whether or not the customer buys treatment: the regulator and the expansion tank.
What the full lesson covers
- Before quoting a softener, check the local sanitation agency: HSC 116786 lets local agencies prohibit self-regenerating softeners that discharge to the sewer, prospectively, and some have. The Santa Clarita Valley Sanitation District's removal ordinance is the enacted example (HSC 116787). Where brine discharge is banned, the options are portable-exchange service or non-salt conditioning.
- A softener exchanges hardness for sodium and discharges brine; a "conditioner" (template-assisted crystallization) reduces scale adhesion without salt or discharge; a filter removes sediment, chlorine, or specific contaminants per its listing. Sell the one that solves the customer's actual complaint, and say what it will not do.
- Every treatment drain discharges through an air gap; every connection to potable water is protected against backflow (CPC 603); treatment units are listed to the NSF/ANSI standard for their claim (CPC 611).
- A regulator is required over 80 psi (608.2) and an expansion tank wherever the regulator or a check prevents expansion (608.3): both are part of the treatment sale because both protect the equipment.
- A softener or whole-house filter is a permitted alteration of the supply; a point-of-use filter under a sink usually is not.
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