Let me explain before I get a flood of reader's emails that we do not need to winterize our boats for freezing temperatures along Southern California's coastline, but we do need to protect our boats from freezing conditions in our local mountains and high deserts. Keep in mind that the temperature only plays a role of how in-depth you will need to perform your winterization.
If you have a trailer boat stored in the mountain areas or high desert, you will have to completely winterize it.
But it's a different matter for boats stored or moored in one of Orange County's harbors.
Because we do not have any lasting freezing temperatures, you do not have to worry about the expansion of ice. Therefore, you do not need to drain your fresh water tanks nor add antifreeze nor blowout the lines to the boat's plumbing. I do recommend that you pump out your holding tank and add in an odor treatment product. A professional tip is to also dry out your sump pumps to keep the unpleasant odor from the organic gases creeping up the drains.
One of the biggest culprits is mold — which loves to grow in dark damp areas — sounds like a boat to me. Wet towels, swim fins, bedding and cushions, basically anything that might grow mold, should be taken off your boat. Open all the cabinet and shower doors to allow air circulation and hang dry towels over the top of the stateroom doors to keep them open.
Do not forget the lifejackets. Wash and sun dry the PFDs while replacing any that are worn or damaged.
Electric dehumidifiers work well if your boat has shore power or you can use the dry chemical dehumidifiers, but you will have to empty the containers once in awhile.