A one minute tutorial to watch and learn quickly
Here’s what we do after a hot tub refill:
Regular draining and refilling are among the most important parts of hot tub care. We usually recommend changing the water every three months, but that can vary depending on how often you use your spa.
In this post (and the video that goes with it), we’ll walk you through exactly how to drain and refill your spa, plus the extra steps we take to keep the water crystal clear from day one.
Over time, your spa water gets saturated with things your body brings in: skin oils, sweat, lotions, minerals, and more. When that buildup reaches a tipping point, it becomes harder and harder to balance the water. That’s when we know it’s time for a fresh start.
Hot tub water needs to be refreshed regularly to prevent bacterial buildup and keep it clean. Warm, moist environments like spas are ideal for bacterial growth, especially when the water isn’t changed often.
Without regular refills, bacteria can multiply to unsafe levels, posing a risk to anyone using the spa. Since multiple people typically use a hot tub, the water can quickly become dirty.
Changing the water also helps eliminate foul odors that develop when water becomes saturated with body oils, sweat, and other organic material. These smells are a sign your water is no longer balanced, even if it looks clear.
Renewing your hot tub water on a set schedule keeps your spa fresh, safe, and enjoyable.
Your filter does half the work of keeping your water clean, but only if it’s in good shape.
We recommend replacing your filter at least once a year. And don’t let your water get too old, either. Saturated water is harder to balance and less effective at staying clean.
In most cases, you should replace the water every three months. If you use your spa frequently, consider doing it more often.
There are a few clear signs that it’s time for a fresh fill:
If you notice any of these, it’s time to drain and refill. Don’t worry, the process is simple, and we’ll show you exactly how to do it.
Draining and refilling your spa is one of the most important maintenance tasks we do as hot tub owners. Here's a step-by-step guide that works for most models:
Always start by switching off your hot tub at the circuit breaker. This protects both you and the spa during the process.
Open the drainage valve and let the water flow out. While it drains, spray down the sides with a hose to loosen any dirt or residue.
Read more: How to Drain a Hot Tub: The Ultimate Expert Guide
Once empty, close the valve and clean the tub with warm water and a mild, spa-safe cleanser.
Be sure to pay extra attention to scrubbing any areas where dirt or grime has built up (like on the jets).
Rinse the tub with clean water until all traces of soap are gone. You can also add any new spa chemicals you want in your diluted form (more on that later).
Use a garden hose to refill the spa with clean water. Leave a few inches of space at the top to prevent overflow when the jets start running.
Once filled, reattach any panels or covers you removed earlier.
The final step is adding chemicals back into your newly filled hot tub. Managing hot tub water chemistry is key to maintaining safe and balanced water. You'll want to add them in their diluted forms to avoid shocking your system and have better control on the chemical levels.
Add chlorine tablets last because it will disinfect everything else in your system as it circulates.
If everything looks good, go ahead and turn your power back on at the breaker box and enjoy.
After refilling your freshly filled hot tub, it's important to follow these extra steps to ensure everything is running smoothly:
Hot tub filters do half the work in keeping your water clean. They remove dirt, debris, and other impurities before they become a problem, helping to prevent cloudy water and even bacterial growth. This bacterial growth could cause skin and eye irritation.
That’s why we check our filters regularly. A quick rinse or timely replacement keeps everything running smoothly and helps maintain water balance.
Don’t ignore dirty filters. When filters are clogged, your pump has to work harder, which can lead to overheating or even equipment failure. In rare cases, it can pose a fire risk. It’s not worth the gamble.
Staying on top of filter care is one of the simplest ways to keep your spa safe and enjoyable.
Make sure you're taking good care of your filters by checking them often!
Hot tub filters offer several advantages for hot tub maintenance, including:
Read more: How To Thoroughly Clean Your Hot Tub Filter
Once your hot tub is refilled, take a moment to inspect all hoses and connections. Even a small crack or slow leak can lead to bigger problems, from water damage to electrical issues if left unnoticed.
We’ve found it’s always easier to catch these issues early, before they become costly repairs.
To help prevent damage down the line, consider using hose covers. They can protect against wear, exposure, and accidental kinks that lead to cracks over time.
Read more: Hot Tub Crack Repair: Quick, Easy DIY Solutions
Check the pH value and correct it if necessary by using a pH + to raise the pH in your hot tub water or a pH - to lower pH levels.
According to the CDC, your target range is 7.2 to 7.8. Within this range, sanitizers such as chlorine or bromine can be effective, keeping your water clean and safe.
It also protects your spa from damage: water that’s too acidic can corrode components, while high pH can cause scale buildup.
Read more: Hot Tub Water Testing: How To Do It Right
The alkalinity level should be between 80 and 120 ppm (parts per million). This ensures that the pH levels stay stable and prevent equipment corrosion.
Think of alkalinity as your spa water’s buffering system. It helps resist sudden changes in pH.
By balancing alkalinity first, you'll make it much easier to keep your pH in check and your water properly balanced.
Keeping your hot tub water properly sanitized is essential. After refilling, you’ll need to choose and add a sanitizer (usually chlorine or bromine) to keep the water safe and free from harmful bacteria.
What matters most is your free chlorine level. This is the portion still available to kill bacteria. Many test strips only show free chlorine, which makes them a good starting point.
Combined or total chlorine includes used-up chlorine, which is no longer effective.
The CDC recommends aiming for:
Chlorine acts faster, while bromine works more slowly but lasts longer in hot water.
To raise sanitizer levels by 5 ppm, here’s a general guideline:
Always check the label. The concentration of active ingredients varies by brand, so these numbers are starting points, not guarantees.
We always retest after mixing to confirm that both pH and sanitizer levels are on target before turning the spa back on.
After adding the sanitizer, you should check and calibrate your pH levels.
You can use a pH test kit, strips, or a digital hot tub water tester to check the levels and adjust accordingly.
Once your pH and sanitizer levels are balanced, it’s time for the final step: add O-Care.
When you pour it in, the water might turn a little cloudy, and that’s a good sign. It means O-Care is doing its job, binding with particles and preparing the water for a cleaner, softer soak. In most cases, it clears up in minutes. If your water quality was poor before the refill, it may take a bit longer.
At this point, assuming everything else is in balance, O-Care is the finishing touch. It helps reduce the need for harsh chemicals, softens the water, and protects your spa from buildup.
Refilling a new hot tub or giving your spa a fresh start isn’t just routine, it’s a key part of keeping your water clean, balanced, and hot tub safe.
Whether you own Hot Spring spas, an inflatable tub, or you’re filling your tub for the first time, following the right steps makes all the difference. Once you've drained, cleaned, balanced, and added O-Care, your spa is ready to go.
Want to keep your water soft, safe, and simple to manage? Find your local O-Care dealer with our store locator.
Emptying and cleaning your hot tub every 3-4 months is typically recommended. This can vary depending on how often you use it, the quality of your water, and other factors.
Yes, you can refill your hot tub with a garden hose. You'll need to ensure the water is clean and contaminant-free. You may also need to add a filter to the hose if your water is particularly dirty.
Heat your hot tub after filling it can take anywhere from a few hours to a day or more. The exact amount of time will depend on your hot tub's size, the water's temperature, and other factors.
No, you should not heat your hot tub while filling it. Doing so can damage the pump and other components.
Yes, you can drain and refill a hot tub in winter. You'll need to take steps to protect the components from freezing. You may also consider using an outdoor hot tub heater to warm the water.
If you need to top up your hot tub water in the winter, add a garden hose or other source of clean water. You'll need to take steps to prevent the components from freezing, such as adding a heater.
No, you do not have to empty a hot tub after every use. You may need to drain and refill it more often if you use it frequently or if the water quality is poor.
If necessary, you can leave your hot tub empty for a week or more. You'll need to take steps to protect the components from freezing and damage. You may also consider using an outdoor hot tub cover to keep the elements out.