Walk-in tubs in older California homes: earthquakes, water rules and old plumbing

Every house has its own story, and California houses have a few common chapters. Earthquakes shaped state rules for water heaters. Droughts shaped rules for plumbing fixtures. And decades of building styles left behind different foundations, pipes and floor framing. None of this should stop a walk-in tub project, but knowing it helps you understand a quote.

Earthquakes: the water heater rule

A walk-in tub holds more water than many standard tubs, and the person fills it in one go while seated. If the existing water heater is small or old, the household may decide to replace it. In California, that triggers a state rule: Health and Safety Code section 19211 requires new and replacement water heaters, and existing residential water heaters, to be braced, anchored or strapped against earthquake motion, at minimum according to the California Plumbing Code. The law applies to standard heaters up to 120 gallons for which a pre-engineered strapping kit is available. When a house is sold, the seller must also certify that the water heater meets this rule.

A water heater replacement usually needs its own plumbing permit, and some homes may also need venting or gas line updates. Make sure the strapping is in the quote and that the heater is sized for the tub you choose.

Drought: the water-conserving fixture rule

California Civil Code section 1101.4 requires that, when a single-family home gets a building permit for alterations or improvements, any noncompliant plumbing fixtures must be replaced with water-conserving fixtures before the building department gives final approval. City forms describe the noncompliant categories as older toilets over 1.6 gallons per flush, showerheads over 2.5 gallons per minute and interior faucets over 2.2 gallons per minute, and many treat homes built after January 1, 1994 as already compliant. Local departments differ on how far the rule reaches. Some apply it to every fixture in the room being altered. If your house still has an original high-flow toilet in the bathroom, ask the installer whether it will need to be replaced to close the permit, and budget accordingly.

Separately, California's appliance efficiency standards (Title 20) limit new showerheads, including hand-held showers, to 1.8 gallons per minute. That applies to the hand shower that comes with many walk-in tubs. These standards cover the showerhead, not the tub's fill rate.

Scald protection

The California Plumbing Code, part of Title 24, limits the maximum hot water temperature from a bathtub or whirlpool tub filler to 120 degrees Fahrenheit, using a temperature-limiting device. This is especially important for older adults. If your tub has an old two-handle faucet, the new installation should bring this up to code.

Foundations: slab or raised

Raised foundations with a crawlspace

Common in many pre-war neighborhoods across Los Angeles, the Bay Area, Sacramento and older parts of the Central Valley. A plumber can usually reach the drain from below, which makes changing drain location or upgrading pipes simpler. Look for signs of past leaks under the bathroom when the crawlspace is opened.

Concrete slab-on-grade

Common in post-war ranch houses and many newer tracts in the Inland Empire, the Central Valley and the desert. If the new tub uses the existing drain, a slab is not a problem. Moving the drain means cutting concrete, trenching and patching. In mid-century Eichler homes, found in parts of the Bay Area including San Jose, Palo Alto and Sunnyvale, radiant heating pipes run inside the slab. Any cutting should be preceded by locating those pipes. The Eichler Network has written about the care these systems need.

Old pipes

• Galvanized steel supply lines, common in homes built before the 1960s, can be narrowed by corrosion inside, which slows filling. Some families replace them in the bathroom while the walls are open.
• Cast-iron drains may be in good shape or badly corroded. A slow drain at the old tub may be a warning sign, and it will also slow a walk-in tub's drain time.
• Older cast-iron tubs weigh several hundred pounds and may need to be broken up for removal.

Electrical in older homes

Tubs with jets or heaters usually need a dedicated GFCI-protected circuit. Older homes with small or crowded electrical panels, or with original wiring, may need panel work before a new circuit can be added. A photo of your panel is one of the most useful things you can send with a quote request.

Condos, HOAs and mobilehome parks

• Condos and HOAs. Many associations require written approval before bathroom alterations, may require licensed and insured contractors, and may limit work hours or require elevator reservations. In large senior communities such as Laguna Woods Village, tub replacement appears on the association's list of alterations that need mutual consent, and a city permit may also be required.
• Mobilehomes and manufactured homes. In many California mobilehome parks, alteration permits come from the state Department of Housing and Community Development (HCD) rather than the city or county. Ask the park office which agency handles permits for your space.

Historic districts

Interior bathroom work in a historic home usually does not need design review, but cities with strong preservation programs, such as Santa Barbara, Pasadena and parts of San Francisco, have rules for exterior changes. If a project involves a new window or vent on the outside wall, check with the planning department.

What this means for your project

1. Tell the specialist the age of the house and whether it is on a slab or raised foundation.
2. Photograph the water heater label and the electrical panel.
3. Note any original toilets, faucets or showerheads in the bathroom.
4. Ask that the quote address strapping, fixture replacement and permits in writing.
5. Confirm the installer's CSLB license before work begins.