Do You Have to Winterize A Pool In California?

Since running a pool service company in the East San Francisco Bay Area of California for the last decade or so, I get this question many times through the fall to the winter months. “Should I winterize my pool?”, or “How much do you charge to winterize pools?” are two of the common questions I get.

The northern and higher elevations of California where freezing temperatures are common, winterizing a pool to some extent is required. On the coastal, southern, and desert areas of the state don’t need to be as concerned with winterizing. Pay close attention to average temperatures throughout the winter months to know if freezing is an issue.

If you are in the temperate parts of the state, winterizing will mean something different than if you live in the colder parts of the state.

What Does It Mean to Winterize A Pool?

Winterizing a pool is a process of closing down a swimming pool or spa in a way that protects it and the equipment from freezing weather. This could include chemical treatment along with physical precautions or actions.

In temperate climates, like the majority of California, ‘winterizing’ a pool is fairly simple. Since freezing temperatures are rare or infrequent, you’ll simply need to watch the weather forecast for possible freezing.

Essentially winterizing in temperate climates amounts to keeping the water moving throughout the winter to prevent freezing.

In colder climates (places where you might wear thermals and a beanie and actually get snow) winterizing a pool is a bit more involved. Depending on the degree of cold as well as the length of time freezing temperatures take hold, there are several steps you can or should take to protect your pool and the attached equipment through the duration of the winter freeze.

Let’s focus first on “sunny” California.

Winterize A Pool In California

To give you an idea of what kind of climate difference there is within California. Looking at the months when it’s the coldest, November to February. In California, you could go from Redding in the north which has an average low of 38°F to Hayward in the SF Bay that has an average low of 45°F to Placerville which is in the Sierra foothills 34°F to SoCal San Diego that averages 51°F.

So you can see freezing temperatures aren’t really a concern for everyone in California. So we can’t really give a blanket answer for the whole state like we might for say New York or Minnesota.

I’ll breakdown first what you might need to know for the more temperate parts of the state, which is by far the majority of those who have pools in California.

Winterize A Pool In A Temperate Climate

If you live in an area of California that rarely if ever, sees freezing temperatures your primary goal is to keep the pool maintained throughout the season just as you would during the summer. Since Algae doesn’t do too well in temperatures below 55°F (13°C) you can taper back the chlorine levels and even the runtime on your equipment to save a few bucks.

But you cannot neglect the pool completely. If you need to know some basics of general pool maintenance, follow this link to our article about that.

Keep an eye on the weather forecast for any of those rare freezing temps. When you see freezing weather coming your way run your pump 24 hours a day to keep the water moving until the weather warms back up. The reason for this is typically on an in-ground pool will keep a slightly warmer temperature than the ambient air so circulating the water when the air temperature is just below freezing will move the warmer water through the pipes and equipment keeping the water from freezing. Even an above ground pool will stay a little warmer due to the ground below it maintaining temperatures.

Most pool automation is equipped with a “freeze protection” circuit that will run the equipment to keep things from freezing up. if it is set up with temperature sensors and a freeze protection circuit you have very little to worry about. If your pool is equipped with a heater, it’s not a bad idea to set it to the lowest possible heat setting to keep things moving. I wouldn’t advise leaving the heater running all winter unless you want to spend a lot of money to heat your pool, but this is a good temporary measure in near-freezing temps.

Winterize A Pool In A Colder Climate

Some might generalize this and say in California winterizing a pool requires less work. That will be true in the above-stated scenarios, but if you have a pool in the sierras and other higher elevations that actually sees winter weather, you will need to take the same exact precautions as those living in the mid-west or eastern parts of the U.S. The only difference is the length of winter in California is much shorter than the majority of the country.

Why winterize a swimming pool in colder parts of California

• To protect your pool vessel and the attached equipment from freezing temperatures. such as bursting pipes, splitting pumps, or rupturing heat exchangers.
• Limit energy and expense throughout the colder months on utilities and maintenance.

Steps to winterize your swimming pool.

These steps are based on and modified from various sources over years of work experience, but the bulk of these following 6 steps are sourced and condensed from The Ultimate Guide to Pool Maintenance by Terry Tamminen. (if anyone has a website reference I will gladly link to it, email info@poolproanswers.com)

1. Balance the chemistry. Etching or scaling will take place in an unbalanced pool. This can leave unsightly scale deposits around the pool or even weaken the pool plaster.
2. Thoroughly clean the pool. Remove all dirt or debris. Dirt or debris left in the pool to settle to the bottom for extended periods will stain the pool and can also affect the overall chemistry balance of the water.
3. Superchlorinate for Algae and stain prevention. In cold California climates, double a normal superchlorination procedure to account for the length of time. For plaster aim for 20 ppm chlorine, on vinyl and fiberglass aim for 10 ppm. Add a chelating chemical like Metal Free from Natural Chemistry to keep any potential stain-causing metals sequestered. Use an algaecide to inhibit potential algae growth.
4. Shutdown the equipment. Inspect all the equipment. Empty pump and skimmer baskets, and give the filter a good cleaning or backwash to make sure there are no problems. This also helps prepare the pool for the spring opening. Turn off the breakers that feed the equipment and lock them out if possible. If you can’t lockout the breakers, place tape over the affected breakers and a sign for any who may try to turn on the breaker.
5. Drain out about 2′-2-1/2′ of water. You want to ensure the water level is well below the skimmer and tile. Freezing water can crack tiles, and it always freezes at the top first. Try not to have the water line near the pool lights either as the lens can break as well. DON’T drain the pool completely for the winter. The water table can damage the plaster and ‘pop’ some portions of the pool vessel.
6. Protect the plumbing. Evacuate all the water from the lines. You can suck the water out or blow it out with compressed air or a wet/dry vac. Use a pool safe glycol antifreeze to add to the pipes. Don’t use automotive antifreeze. Using a long pipe you can add the antifreeze to the bottom main drain.
7. Install a winter cover. This is not a thermal cover or bubble cover. This is a high strength anchored cover that will prevent debris and even hold up to the weight of snow. Keeping debris out of your partially drained pool will keep it from turning a nice shade of green over the winter. It’s as close as you get to a hermetically sealed swimming pool until the spring.

The above steps are somewhat extreme in some cases and not all of them will be necessary, but if you have ever had a burst pipe you can appreciate that sometimes an ounce of prevention is indeed worth a pound of cure.

Should You Just Drain Your Swimming Pool In the Wintertime?

While winterizing may seem like a lot of work, draining your pool may seem like an easier option. Yes, it may SEEM like an easier option. Draining your pool always has a potential risk for damage. This little thing called hydrostatic pressure can ruin an empty swimming pool. In basic terms, the water table, or groundwater, tried to turn an empty pool into a boat. It may not lift the entire pool out of the ground, but given enough time and circumstance, it can crack and pop large sections of the pool vessel.

A temporary draining may be fine, but if water tables rise during the winter or just the continued pressure on the pool, this can be a very expensive mistake.

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