When real property is transferred in California, there may be some required retrofits of your home, if your home is not presently up to code in some respects.
These are usually minor, and include installation of smoke and carbon monoxide detectors, and also that the water heater(s) be seismically strapped. Smoke and Carbon Monoxide detectors are fairly inexpensive, and can be had for as low as $10 apiece – or even less. Seismic strapping might up to $125 for parts and labor installed by a contractor, or considerably less than that if you do-it-yourself. Depending on the location of your property, the local government may require that the toilets and shower heads be low-flow fixtures The shower heads are very inexpensive and not a concern; toilets run about $250 apiece, installed.