With freezing temperatures on the way, now is the time to winterize your pool equipment. Using antifreeze in supply lines prevents damage from bursting pipes — but is it worth trying to make your own homemade mix versus buying commercial products? We’ll review if it’s possible, as well as give you all the information you need to know about anti-freezing your pool.

    Can You Make Your Own Antifreeze for Pool Lines?

    At anywhere from $15 to $30 per gallon, pool antifreeze can get pricey — especially if you have long supply lines. So what do you need to make your own and avoid the price tag?

    propylene glycol solution
    Image Credit: Canva

    Pool antifreeze is generally a propylene glycol solution, sometimes mixed with alcohol or other additives and sometimes just diluted with water. You can purchase propylene glycol in bulk – one source I found was The Chemistry Store

    If you decide to make your own solution, I would recommend getting some sound advice from a chemist or pool specialist regarding the correct proportions and type of water (distilled, etc.) you should use, as well as the proper procedure for storage and disposal of propylene glycol.

    Pool line antifreeze will eventually end up in your pool water, so don’t try to cut corners by substituting auto antifreeze or any product with ethylene glycol – even at low concentrations. The ethylene glycol reacts with pool chlorine to form toxic chlorinated hydrocarbons in the water.

    The Benefits of Using Antifreeze in Pool Lines

    Using antifreeze in your pool’s supply lines provides important cold-weather protection. Without antifreeze, any water remaining in the pipes can freeze and expand, potentially rupturing the lines. This can lead to costly repairs and leak issues in the spring.

    Antifreeze lowers the freezing point of the water in the pool’s pipes. This prevents ice crystals from forming and damaging the lines even when temperatures dip below freezing. As a result, you can avoid scrambling to winterize lines at the last minute if an unexpected cold snap occurs.

    Another advantage of antifreeze is convenience. It removes the need to blow out or drain the pipes with compressed air each fall. Adding antifreeze is a relatively quick process that doesn’t require specialized equipment.

    Pool owners with in-ground vinyl liner pools must be especially diligent about using antifreeze. If groundwater seeps into unprotected pipes and freezes, it can warp the vinyl liner behind the pool wall when it expands. This causes unsightly wrinkles and may even require liner replacement.

    Choosing the Right Type of Antifreeze

    With so many antifreeze products available, it can get confusing to choose the right one for your pool. However, it’s crucial to select a non-toxic propylene glycol formula specifically designed for pool systems.

    It’s crucial to use the right type of antifreeze in pool supply lines. Automotive antifreeze contains ethylene glycol, which is toxic — and when it mixes with ‌pool water, the chlorine can react with the ethylene glycol and form hazardous compounds.

    Instead, you’ll want to opt for propylene glycol-based RV antifreeze or a commercial pool line antifreeze product. Propylene glycol is non-toxic — this makes it safe for pipes that supply water to the pool. Check that the antifreeze is concentrated propylene glycol, not a weaker premixed solution. The concentrated product has a lower freezing point to handle frigid temperatures.

    Be sure to get food-grade propylene glycol designed for drinking water systems. You’ll want to avoid industrial-grade antifreeze, which may contain questionable additives.

    Today’s Homeowner Tips

    Look at the manufacturer’s specifications to confirm the antifreeze protects down to the appropriate temperature based on winter lows in your climate zone. Using an antifreeze rated for -50°F provides protection even during an extreme cold snap.

    How to Add Antifreeze to Pool Lines

    Adding antifreeze to exposed pool lines that run above ground is straightforward. Simply pour the antifreeze into the pipes through the return fitting until it begins flowing out the other end. If needed, use a funnel to carefully direct the antifreeze into the opening without spilling.

    For buried pool plumbing, you’ll want to connect a short section of the hose to the return fitting so you can route the antifreeze exactly where it needs to go. Add enough antifreeze until you see it discharge from the return jets in the pool or coming up through backwash ports in the filter system.

    Plan on using two to three gallons of concentrated antifreeze for every 100 feet of 1.5” pipe. For larger diameter pipes or long runs, you may need significantly more. Apply the antifreeze slowly to allow it to flow through the system. When finished, blow out any remaining puddles of antifreeze from the lines using compressed air if possible.

    Always refer to the antifreeze manufacturer’s instructions for proper dosage rates and application procedures. Never exceed the recommended dilution ratio.

    Tips for Reducing Costs

    Since antifreeze can be expensive, especially for large pools, look for ways to use less:

    • Add antifreeze primarily to places that tend to hold water, like the bottom of pipes or low spots where drainage is poor.
    • Buy antifreeze in bulk quantities to get a discounted per-gallon price. Storing excess antifreeze is fine as long as you tightly seal the containers.
    • If you have a pool cover, consider leaving more water in the pool and lines over winter. The cover helps prevent surface freezing, reducing risk.
    • Only treat the most vulnerable pipes and components. If some plumbing runs below the local frost line, it may not require antifreeze.
    • Reuse antifreeze for several seasons since propylene glycol does not degrade over time — simply top it off each fall.
    • Shop end-of-season sales in early fall when retailers are trying to clear out inventory of seasonal products.

    Improving Drainage

    Improving drainage in pool plumbing can allow you to use less antifreeze. The key is to minimize any low spots where water collects. Any puddles not displaced with antifreeze are prone to freezing.

    Check areas near valves, elbows, pipe joints, and equipment connections for low spots. If needed, re-route, or slope plumbing to promote better drainage. Blowing out lines with compressed air also helps evacuate pockets of standing water.

    Installing drains at the low end of plumbing runs allows water to exit the pipes when blown out. This helps remove the bulk of the water before adding antifreeze. Drainage caps fitted with a stop plug help control water flow when draining lines while still allowing future access.

    Storing Antifreeze Safely

    Take steps to store pool antifreeze properly:

    • Avoid direct sun exposure and extreme heat, which can degrade the antifreeze over time.
    • Keep it tightly sealed and label the contents clearly.
    • Never reuse food, beverage, or other household containers to store chemicals.
    • Store in a locked area away from children and pets.

    Having a dedicated chemical storage shed keeps all your pool chemicals safe and organized in one place. Make sure the storage area has proper ventilation.

    Never mix different pool chemicals together or store them near other hazardous materials. Pool antifreeze is generally non-reactive, but it’s still smart to store it separately just to be safe.

    Disposing of Antifreeze Properly

    Check locally to determine if your municipality allows dumping diluted pool antifreeze down the sanitary sewer system. Many areas prohibit this practice since propylene glycol can encourage bacteria growth at treatment plants.

    Instead, the best way to dispose of old antifreeze is through a hazardous waste collection program. Some retailers also accept antifreeze and other chemicals for proper disposal as a community service.

    Never dump pool antifreeze down a storm drain or into a septic system. This illegally discharges chemicals directly into the environment, which can pollute groundwater and harm wildlife. You’ll want to follow all laws and regulations when disposing of pool chemicals of any type.

    So, Is Homemade Pool Line Antifreeze a Good Idea?

    Making your own homemade pool line antifreeze can certainly save money compared to buying premade commercial products. However, the process requires great care to get the mixture right and to handle the concentrated chemicals safely. There is also some regulatory uncertainty around legal disposal methods for homemade solutions.

    Ultimately, for most residential pool owners, purchasing a quality commercial antifreeze is the easiest and safest option. The modest additional cost provides peace of mind knowing the product is EPA-approved and made to the proper specifications by qualified pool chemical manufacturers. Unless you have extensive plumbing runs or operate a large commercial pool, homemade antifreeze is probably more trouble than it’s worth.

    FAQs About Pool Line Antifreeze

    Does all pool plumbing need to be treated with antifreeze?

    Only pipes and components that will hold water after draining will require antifreeze. Sections that run below the local frost line can be drained and left empty over winter.

    How often do I need to add fresh antifreeze?

    You only need to replace all the antifreeze every few years. Just top it off each fall as needed. Test kits are available to check freeze protection levels.

    What temperature does pool antifreeze protect to?

    Antifreeze concentration and protection levels vary. A typical commercial product protects down to around -50°F. Higher concentrations safeguard plumbing at -100°F or lower.

    Can I use mineral spirits instead of antifreeze?

    No, mineral spirits have a high freezing point and won’t protect pipes from bursting. You’ll want to only use propylene-glycol-based antifreeze.

    Is it OK to leave pool plumbing full of water over winter without antifreeze?

    Only if the pipes run below the frost line. You must treat any above-ground plumbing with antifreeze if it holds standing water.

    Editorial Contributors
    avatar for Jonathon Jachura

    Jonathon Jachura


    Jonathon Jachura is a two-time homeowner with hands-on experience with HVAC, gutters, plumbing, lawn care, pest control, and other aspects of owning a home. He is passionate about home maintenance and finding the best services. His main goal is to educate others with crisp, concise descriptions that any homeowner can use. Jon uses his strong technical background to create engaging, easy-to-read, and informative guides. He does most of his home and lawn projects himself but hires professional companies for the “big things.” He knows what goes into finding the best service providers and contractors. Jon studied mechanical engineering at Purdue University in Indiana and worked in the HVAC industry for 12 years. Between his various home improvement projects, he enjoys the outdoors, a good cup of coffee, and spending time with his family.

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    Jeff Zoldy

    Jeff is a writer, editor, and marketer based in Charlotte, North Carolina. He has been editing on the Home Solutions team for over a year and is passionate about getting homeowners the information they need when they need it most. When he’s not working, Jeff can be found at baseball games, golfing, going to the gym, reading, watching movies, and playing video games.

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