How Often to Drain Hot Tub?

In this post, we provide you with information about how often to drain hot tubs and how to know when it's time to drain them. We also explain the benefits of draining hot tubs regularly.

A hot tub is a great way to unwind after a stressful day. However, you need to remember that your pool is a closed system, meaning bacteria and algae are everywhere. If the water stays stagnant long enough, pathogens can grow rapidly and make your hot tub unsanitary. This calls for a complete drain. But how often we need to drain our hot tubs depends on certain factors, so it might be different for everybody.

How Often Should I Drain My Hot Tub?

Typically, hot tub water needs to be replaced every three months. Over time, your sanitizers will stop working, and your hot tub water will turn cloudy or foamy, no matter how much you sanitize it. Contaminants, bacteria, and algae can build up after months of use and overwhelm your sanitizer system.

However, some people use their hot tubs more frequently or share them with more than one person. This can accelerate the buildup of contaminants and pathogens. In this case, draining should be done every month or immediately if the water turns cloudy, foamy, or slimy after a night of heavy use.

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It's also important to drain your hot tub before winter comes. If you don't, you might end up with a lot of mold growth. You should open the valve so that all the water drains from the system. You can also use the pump to remove any remaining water.

When you're ready to refill the spa, make sure to add fresh water first. This will help prevent algae and other bacteria from growing. After adding the new water, close the valve. The water level shouldn't drop below two inches.

Signs It's Time to Drain and Refill My Hot Tub

To determine when to drain your spa, look for signs of mildew, rust, and mold growth. These issues usually happen when the hot tub hasn't been drained for a while so take note of them immediately. Or, as we said earlier, when you notice your hot tub water turning cloudy, foamy, or murky, you definitely need to drain your hot tub. Adding sanitizers at this point wouldn't help. You can use a hot tub clarifier in a pinch, e.g., you need to use the hot tub for tonight's party, but you'll have to replace the water after use.

signs its time to drain and refill my hot tub

The Best Way to Drain a Hot Tub

You must thoroughly drain your hot tub, including the plumbing lines. Simply draining your hot tub could leave some of the algae and pathogens behind, particularly in your hot tub's plumbing. To remove the biofilm that's been built up in these hard-to-reach areas, you might as well do a hot tub flush.

If you plan on not using your hot tub during the cold months, you should also add antifreeze into your plumbing to prevent ice from forming and damaging your hot tub.

the best way to drain a hot tub

As much as possible, you want to drain your hot tub only when necessary. Frequent drain and refills will increase your water bill significantly. Moreover, refilling and sanitizing your hot tub can take hours or even a day. Keeping your hot tub sanitized is critical. That way, you won't have to drain your hot tub frequently.


Knowing when to drain your hot tub and how often ensures your hot tub is a safe and enjoyable experience for everybody. Only change your hot tub water when necessary and do it thoroughly, which means flushing your plumbing as well. With regular maintenance, it would take three months before you have to drain your hot tub, saving you money on water bills and sanitizers.