Hot tubs can take as long as 2 hours to empty fully using the drainage spigot. The good news is that the time can be significantly reduced with the right equipment.
By using a submersible pump, you can reduce the amount of time it takes to drain your hot tub to as little as 6 minutes for small spas and 21 minutes for very large spas. Another quick way is to siphon the water using a wet/dry shop vacuum fitted with a wide-diameter hose.
For me, it’s a no-brainer to own both. The submersible pump makes light work of draining, and the wet/dry shop vacuum comes is worth its weight in gold for removing the last inch or two of water left at the bottom.
Submersible pump
The fastest method for draining a hot tub is using a submersible pump with automatic shut-off
. It can be attached to a much wider-diameter hose than a conventional garden hose, making it pump out water faster.
The faster the pump flow rate, the faster the draining speed. For instance, a submersible pump working at a typical rate of 33 gallons per minute will empty a 200-gallon spa in 6 minutes.
Such a flow rate is equivalent to 2,000 gallons (7,600 liters) per hour. Here is a table demonstrating how long it’ll take to drain your spa at that rate.
| Hot tub capacity (gallons) | Hot tub capacity (liters) | Drainage time (minutes) |
|---|---|---|
| 200 | 750 | 6 |
| 300 | 1100 | 9 |
| 400 | 1500 | 12 |
| 500 | 1900 | 15 |
| 600 | 2300 | 18 |
| 700 | 2650 | 21 |
Apart from its speed, another great feature of the submersible pump is its sensor that automatically turns the pump off once the hot tub has emptied.
Before you start draining your spa, you must choose a legal drainage point. Emptying your hot tub water in the wrong place can lead to problems like hefty fines and environmental hazards. Always check the rules around spa water disposal in your city.
How to drain a hot tub with a submersible pump
Tools required
- Hose
- Submersible pump
- Float switch (if pump lacks one)
- Filter screen
Step-by-step guide
- Choose a safe and legal drainage point.
- Cut the power to your hot tub to keep the jets from running the pump dry.
- Attach a hose to the hose fitting on the pump.
- Ensure the float switch to the submersible pump is connected. If your pump lacks one, you’ll need to connect one yourself.
- Connect the pump’s power cord to a nearby power source.
- Pour water through the pump to prime it.
- Attach a filter screen to the pump to prevent it from sucking in debris.
- Submerge the pump into the deepest side of the water. It will automatically kick on.
- Monitor the progress of the pump as it works and watch the water level closely.
- Check if the float switch has turned the pump off. Remove any debris that might prevent a smooth operation of the pump.
- Once the water level is too low for the pump to drain, turn it off immediately to prevent it from running dry and becoming damaged.
Wet/dry shop vacuum
Another speedy way to drain a hot tub is to initiate a siphon using a wet/dry shop vacuum, also known as a wet/dry vac.
This method might not be as fast as using a submersible pump, but it is still a quick and efficient way of emptying a hot tub.
The vacuum’s large diameter hose makes it more effective than a regular garden hose. Another valuable feature of the wet/dry vac is its “wand” end which you can use to remove debris and other small particles from the seats and floor of the tub.
How to drain a hot tub using a wet/dry vac
Tools required
- Hose
- Wet/dry vacuum
Step-by-step guide
- Turn off the hot tub and unplug it from the electrical source.
- Place one end of the vacuum’s hose into the hot tub.
- Attach the other end to the vacuum.
- Turn the wet/dry vac on for a few seconds, long enough to prime the hose and instigate water flow.
- Switch off the vacuum and immediately disconnect the hose to allow the water to flow into the drainage point.
How to remove the remaining water from the bottom of your hot tub
When using a submersible pump, there is always an inch or two of water left at the bottom of the tub. This should be cleared out so that you can clean the hot tub shell with a chemical surface cleaner to disinfect and remove tough scum.
The most efficient way to remove the water is to use a wet/dry vac. First, remove the submersible pump when the water level is too low for the siphon to suck out more water.
Next, turn on your wet/dry vac and vacuum the water from the seating areas, and footwells. If you don’t have a wet/dry vac, you can use towels to mop up these last bits of water.
When emptying your tub, ensure you get rid of every last drop. The water is unhygienic and can cause mold to grow in and around your hot tub jets. Completely ridding your spa of water also makes it easier for you to clean and disinfect the tub.
Don’t forget to remove any biofilm before draining
Before draining your hot tub, you should use this Ahh-Some line flush cleaner to clear out any traces of toxic biofilm lurking in the plumbing.
Getting rid of biofilm in the pipes ensures that the water is as fresh as possible after filling back up. Any bacteria left behind will play havoc will your water chemistry, taking you right back to square one.
A wet/dry vacuum can easily suck and/or blow the water out. Another option is to utilize the spa’s air blower if yours has one. Before using the blower, ensure the jets are open. Don’t forget to turn the power off after using the air blower.
