How to fill a hot tub

How to Fill a Hot Tub

Hot Tubs


October 2, 2023

Properly filling your hot tub is an important part of the initial set-up of a new spa and a crucial part of continuing hot tub maintenance. How hard can it be? Just turn on the water, right? Though it seems like a simple task, there are actually some important elements that require attention and consideration when draining and filling a hot tub.


How do I drain and refill a hot tub?

The following are several steps and considerations to keep in mind when draining and filling your spa. 



  • The water you use should be free of metals (copper, iron, and manganese) and low in calcium (hardness). Test your tap water or your well water before beginning.
  • Use a pre-filter. It helps to correct alkalinity and pH issues in all water sources (including well water). 
  • Try adding an enzyme-based formulation to the new water to reduce the need for chemicals.


Steps for draining and refilling:

  • Add a full bottle of plumbing cleaner such as Purge to the hot tub water. Run the spa for one hour, then leave the cleanser in the water for another 23 hours. 
  • Turn off the power supply to the hot tub. 
  • Drain the hot tub by attaching the garden hose to the spa drain valve.
  • Utilize a shop vac to remove the remaining water in the bottom of the spa and in the plumbing. 
  • Close the drain and wipe the tub clean.
  • Place the garden hose in the filter/skimmer area and turn it on. This lets the pump fill with water first, preventing airlock issues when the hot tub is turned on. 
  • Fill until the water level is above the top of the highest jet and/or look for a water fill line on the interior of the tub.
  • Switch the power on. 
  • Use the up or down temperature buttons to select the optimal temperature. 
  • Close the hot tub cover, enabling the hot tub to heat faster and keeping debris from entering the spa.
  • Allow the hot tub to heat for at least five hours before adding additional chemicals.
  • Employ test strips to test the water. 
  • If pH or alkalinity levels are not correct, adjust with either pH Reducer or pH Booster. Adjust the alkalinity level first.
  • When the water reaches the desired temperature and is properly balanced, disinfect the water by adding sanitizer
  • Leave your spa cover open for 1 pump cycle (approximately 20 min.).

At this point, your spa is ready to use. If you have any questions and/or concerns refer to the manufacturer’s manual and/or call your dealer for advice and help. 


How to fill a hot tub for the first time?

Filling your new hot tub for the first time is an almost identical procedure to draining and refilling your spa (see the above steps). Start by filling the new tub with water through the filter housing. Remove your filter and put your hose down the hole. This will prevent an air lock on most standard hot tubs. Always refer to your users manual for start up procedures. Run the pump for a few minutes to flush the system. Drain and continue with the steps outlined above. 


How high should I fill my hot tub?

How high to fill a hot tub is determined by the fill line found on the interior of the spa. Alternatively, fill until the highest jet is covered. 


How long does it take to fill a hot tub?

It takes approximately 30 to 90 minutes to fill a hot tub, depending on the size of the spa, hose size, and the water pressure.

Having a hot tub in your backyard is an exciting adventure! It’s a great place to relax and spend time with family and friends. Properly draining and refilling your hot tub is part of ongoing maintenance that ensures your spa is safe and sanitary. 

Need advice on draining, cleaning, and refilling your hot tub? Looking for quality chemicals and accessories? R&R’s hot tub experts are here to help you. Owned and operated by service professionals with more than 30 years of experience, and carrying prestige brands including Vita Spa and American Whirlpool, we make your spa purchase exceptional. Call us at 403-203-0860 to set up an appointment.

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