California's Required Seller Upgrades: Smoke Detectors, CO Alarms, and Water Heater Strapping

What do California sellers have to certify before closing?

California law requires sellers to certify that their home has working smoke detectors, carbon monoxide alarms, and a properly braced water heater before escrow closes. These are mandatory compliance items. Missing any of them can delay your closing, trigger last-minute repair demands from buyers, or expose you to liability after the sale.

By Paul Blair | July 7, 2026

Most LA sellers know they'll need to fill out a Transfer Disclosure Statement. They expect questions about permits, roof age, and whether the foundation has ever moved. What catches a lot of people off guard are the mandatory compliance certifications: the smoke detectors, the CO alarms, and the water heater strapping.

These aren't optional. They're required by California state law, and you have to certify compliance before close of escrow. Buyers and their agents check for them. Escrow companies track them. Miss one, and you're looking at last-minute negotiations when you'd rather be packing boxes.

Here's what you need to know before you list.

The Three Requirements

Smoke detectors

California Health and Safety Code requires smoke detectors in every bedroom, in every hallway outside a sleeping area, and on every level of the home, including basements. If your home has an attached garage, you need a detector there too.

There's a specific rule about battery-only units. Any battery-powered smoke alarm sold or installed in California must use a sealed, non-replaceable battery capable of powering the unit for at least ten years. Those old 9-volt battery detectors won't pass. If yours chirp every few months and you swap the battery, they're likely not compliant.

In the City of Los Angeles, the requirements go a step further. Many attached homes (condos, townhomes, and homes sharing a wall) are required to have hardwired smoke detectors with battery backup rather than standalone battery units. If you're selling anywhere in Beverly Grove, West Hollywood, or a mid-century attached property in Sherman Oaks or Studio City, confirm what's required for your configuration before you list.

The manufacture date matters here too. Smoke alarms more than ten years old must be replaced, regardless of whether they still function. The date is typically stamped inside the cover of the unit.

Carbon monoxide alarms

If your home has a gas appliance, a gas fireplace, any type of fireplace, or an attached garage, California requires at least one CO alarm. The alarm must be installed on each level of the home and outside each sleeping area.

Homes with no fuel-burning appliances and a fully detached garage are exempt. But in Los Angeles, most homes in the price range you're selling have at least a gas range or a fireplace. Count on needing CO detectors if you're selling anywhere in the Hollywood Hills, Bel Air, Brentwood, or the Westside.

Like smoke alarms, CO detectors have a limited lifespan. Most manufacturers recommend replacement every five to seven years. If yours are old, replace them before listing. It's a thirty-dollar fix that won't make you any money, but missing it can cost you time and negotiating leverage.

Water heater strapping

California Health and Safety Code Section 19211 requires all residential water heaters to be braced and strapped to protect against earthquake movement. This isn't specific to hillside properties or high fire hazard zones. It applies to every home in the state.

The strapping must meet specific requirements: two attachment points, positioned at the upper third and lower third of the tank, using heavy-gauge metal straps secured to wall studs (not just drywall). A basic strapping kit runs twenty to thirty dollars at any hardware store, and most plumbers or handymen can finish the job in under an hour.

Before you close, you'll sign a Water Heater and Smoke Detector Statement of Compliance. It's a separate document from the Transfer Disclosure Statement, and escrow will track it. If you can't certify, you'll need to either complete the work or negotiate with the buyer over who handles it.

How These Items Come Up in Your Transaction

Most sellers first hear about these requirements from their agent at the listing appointment, or they see the items flagged in the buyer's home inspection report.

If your inspector checks for compliance (most do), they'll call out any detectors that are outdated, incorrectly placed, or non-compliant. If the water heater isn't strapped, that shows up too. At that point, it becomes a negotiating point.

You have a few options when something gets flagged. You can complete the work before the inspection happens, which is the cleanest path. You can offer the buyer a credit at close to handle it themselves. Or you can negotiate it as part of a broader repair request response.

What you want to avoid is letting compliance items become leverage for larger credits or price adjustments. These are cheap fixes when you handle them proactively. They get expensive when buyers bundle them with inspection repair requests, especially if escrow is already moving and timelines are tight.

If you're weighing whether to order a pre-listing inspection before you go on market, one of the clearest benefits is catching these compliance gaps before any buyer does.

Timing: Handle This Before You List

The best time to address all three items is before your home goes on the market. Walk through the house yourself ahead of your listing appointment. Count the detectors, check the manufacture dates, look at the water heater connections. If anything is missing or past its service life, take care of it then.

Your listing agent should walk you through this checklist anyway. If they're not asking about smoke alarms and water heater strapping at the pre-listing meeting, raise it yourself. Getting caught at inspection is a solvable problem. Getting caught late in escrow, after contingencies are removed and everyone's timeline is locked, is a much harder situation.

What Buyers Can and Cannot Require

California law doesn't require you to bring your home fully up to current building code when you sell. But it does require compliance with these specific items.

That distinction matters. If your home was built in 1965 and has single-pane windows throughout, a buyer can't force you to replace them as a legal condition of the sale. But if you don't have working smoke detectors in the right locations, you are legally required to address that before close.

Some buyers, particularly those purchasing in neighborhoods with older housing stock (Los Feliz, Silver Lake, certain parts of the Hollywood Hills), will push for additional safety features beyond what's legally required. A working home warranty, updated electrical panels, added detector coverage. These are negotiating points, not legal requirements. Know the difference. Your agent should be able to tell you clearly what's mandatory and what's optional when you're reviewing a repair request.

Frequently Asked Questions

What happens if I sell a California home without working smoke detectors?

You're required by state law to certify compliance before the sale closes. Selling without meeting the smoke detector requirements puts you at risk of legal liability, and your escrow company will typically require the signed compliance statement before disbursing funds. If you close without complying, a buyer could potentially pursue a civil claim.

Does California require CO detectors in all homes?

No, but the exemptions are narrow. If your home has no fuel-burning appliances (no gas range, no fireplace, no gas water heater) and the garage is fully detached from the living space, you may be exempt. Most Los Angeles homes, including hillside properties and older construction across Beverly Hills and Studio City, have at least one fuel-burning appliance and will need CO detectors.

Who pays for water heater strapping in a California home sale?

There's no legal rule that the seller must pay. But sellers are required to certify compliance before escrow closes, so in practice, sellers typically handle it before listing or negotiate a credit if it surfaces during inspection. The cost is usually under $150 with labor, making it simpler for most sellers to complete it rather than leave it as an open negotiating point.

Do I have to replace my smoke detectors if they're still working?

If they're more than ten years old, yes. California law requires replacement at the end of the manufacturer's stated service life, which is typically ten years. The manufacture date is stamped inside the housing. A detector that passes functional tests but is past its ten-year life doesn't meet the legal requirement.

Does the City of Los Angeles have stricter requirements than state law?

Yes, in some cases. LA City requires hardwired smoke detectors (with battery backup) in certain attached residential properties. If you're selling a unit with shared walls in West Hollywood, Beverly Grove, or any higher-density part of the city, check both state and local requirements before assuming battery-only detectors are sufficient.

Most of the compliance work in a California home sale is paperwork. These three items are the exceptions: physical changes to the property that have to be done and certified before you can close. The good news is they're inexpensive and straightforward. Smoke detectors and CO alarms run fifteen to thirty dollars each. A water heater strapping kit costs under thirty dollars and takes an afternoon.

Handle them before you list, and they become a non-issue. Let them slip, and they become leverage for buyers who are already looking for reasons to negotiate.

If you're thinking about listing in Los Angeles and want to know exactly what your home will need before it hits the market, reach out to the Grey Square team at greysq.com/contact. If you're curious where your home stands value-wise, get a live estimate at greysq.com/home-value.

About Paul Blair Paul Blair is the founder and broker of Grey Square, a virtual real estate brokerage representing buyers and sellers across Dallas and Los Angeles. With 22 years in the business and more than $200 million in closed transactions, Paul works the full range of the market, from luxury homes in the Park Cities and Preston Hollow to estates in the Hollywood Hills and across the Westside. Connect with Paul and the Grey Square team at greysq.com. TX TREC #9011505 · CA DRE #01792671.