How often should I drain my hot tub

How Often Should I Drain My Hot Tub?

Hot Tubs


December 7, 2022

Draining and refilling your hot tub is a hassle! Many owners avoid this simple yet crucial detail of care. However, draining and refilling are important parts of keeping your water clean and safe. Refilling and rebalancing the water prevents damage to the spa and protects users.

Why do I need to change the water in my hot tub? 

Hot tub water can hold only so many chemicals before it becomes supersaturated and difficult to balance and maintain. Each time you use your spa you leave behind contaminants (sweat, shampoo, lotion, body oil, laundry soap, deodorant). Once contaminants reach a certain level they prevent the water from dissolving the chemicals needed for safety. 

Signs that it’s time to drain my hot tub

  • Foamy water: If antifoam agents such as SPA LIFE Foam Away don’t reduce the foam in your tub, it’s time to change the water. 
  • Filmy or discoloured water also signals a need for a change. 
  • Smelly water: If you notice an unusual odour, you’re due for a drain and refill. 
  • TDS – When your total dissolved solids are high and your PH and Alkalinity are hard to balance, it’s usually time to replace your water.

Factors that affect how often should I drain my hot tub

Many hot tub companies recommend that you change the water in your spa every three to four months. While this is not bad advice, the truth is that how often should you drain your hot tub is dependent upon a number of factors. 

Initial water quality

  • Hard water/well water is naturally pure and without additives. However, well water often has high levels of metals (copper, lead), microorganisms and minerals (calcium, magnesium). It may leave a residue, which, though not dangerous, can be annoying. Homeowners with well water will need to take advantage of scale defence products in order to extend the time before they need to drain and refill. Eco One Monthly and Spa Marvel reduce scum lines while Aqua Cop Out helps reduce metal build-up!  You can also add an x10 Water Filter to get bottled water levels of purity!
  • Soft water is treated and has little if any calcium and magnesium. It can corrode metal surfaces inside the hot tub. The key to extending the time before you need to drain and refill is to increase the water hardness by adding calcium chloride with a product such as AquaCal.

The quality of your chemicals

To extend the time between water changes, use the right chemicals and use high-quality chemicals. Inferior chemicals leave behind solids (fillers, binders, glues) which cause cloudy water and require more chemicals to fix the problem. High-quality chemicals not only leave behind fewer solids, but they can also be used in smaller quantities and still produce good results. 

Improper use of chemicals

Poor water chemistry, over-correction of the chemicals and the addition of substances you don’t actually need can all contribute to shortening the expected lifespan of the water in your hot tub.

The spa filtration/purification system

The higher the quality of your spa’s filtration/purification system the longer you can go before you need to drain and refill. American Whirlpool spas utilize a four-step cleaning system and dual sanitation features which make the waters of these spas safe for your family’s usage. This water treatment system is used to sanitize drinking water all over the world! 


Whether the spa is used occasionally or daily and how many people use the spa will determine how often you need to drain and refill. Do you shower before jumping in the hot tub? This will reduce your need to drain. Do you have the occasional hot tub party on the weekends? This may speed up the need for a change of water. 

Bath products and oils

If you add bath products and oils to your hot tub you’ll likely increase the frequency that you need to drain and refill as both oils and salts can build up in the water over time. 


Is your spa located under or near trees? Is it surrounded by mulch, dirt or gravel? Where your hot tub is located can affect how much debris enters it and how often it will need to be drained and cleaned.

When is the best time to drain and refill my hot tub?

It’s unwise to drain and refill your hot tub in the extreme cold of winter as you run the risk of the water in the lines of your spa freezing before you can refill and reheat. Instead, drain late in the fall and again early in the spring. If you absolutely must drain in the cold, only drain half the water, then refill and reheat. This will improve your water quality enough to get you through to warmer weather. 

How to drain and refill a hot tub: 5 steps

  1. Prepare: The first step when preparing to drain your hot tub is to clean out the plumbing. To do this you’ll need a specialized plumbing cleaner like Purge. Add 1 full bottle to your existing spa water, run on high speed for 1 hour and then leave the cleanser in the spa for at least 23 hours. 
  2. Drain the tub: First, turn off the power to the hot tub. Attach your garden hose to the hot tub’s drain. Put the other end of the hose where you want the waste water to go and open the drain valve. Alternatively, use a small submersible pump, but be aware of local bylaws!
  3. Clean: Once draining is complete, use a shop vac to remove the remainder of the water in the bottom of the hot tub. Put the end of the shop vac hose up to the jets and suctions to remove the remaining water in the plumbing. Spray the shell and underside of the cover with a non-sudsing hot tub cleaner like Spa Life Clean. Remove it with paper towel or a soft cloth.
  4. Refill the hot tub: Close the drain valve and remove your garden hose. Fill the spa from the filter area. This allows the pump to fill with water first, preventing potential airlock issues when you turn the hot tub on. When the hot tub is filled, turn the power back on and let the hot tub heat up.
  5. Add chemicals: When the hot tub has heated to approximately 20 degrees Celsius, add your initial chemicals.

How often should you drain your hot tub depends upon how well you maintain your water, how many people use the tub, how often the tub is used, where the tub is located and the quality of chemicals added. Watch for the signs that indicate it’s time to drain and refill your spa. Mark your calendar each time you change the water. You’ll quickly become aware of just how often your individual hot tub will need draining and renewing. 

Need advice on cleaning and refilling your spa? Interested in quality chemicals and accessories to improve your hot tub experience? Contact Calgary-based  RnR hot tubs and spas. We carry a full line of hot tub accessories. Call (403) 203-0860 or fill out the contact request. RnR provides comprehensive service, expert knowledge, a wealth of field experience and the best products in the industry to help you maintain your hot tub/swim spa for years of enjoyment. RnR is Alberta’s premier hot tub/swim spa store specializing in the World’s First Steel Framed Spas from American Whirlpool, Vita Spas and MAAX Spas.

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